Bitcoin Wiki

"it is possible to securely verify that a transaction has been accepted by the network by downloading just the tiny block headers and Merkle tree -- downloading the entire block chain is unnecessary. This feature is currently not used in Bitcoin, but it will be in the future." - Wiki article, 12/10

submitted by PixMasterz to Buttcoin [link] [comments]

Bob The Magic Custodian



Summary: Everyone knows that when you give your assets to someone else, they always keep them safe. If this is true for individuals, it is certainly true for businesses.
Custodians always tell the truth and manage funds properly. They won't have any interest in taking the assets as an exchange operator would. Auditors tell the truth and can't be misled. That's because organizations that are regulated are incapable of lying and don't make mistakes.

First, some background. Here is a summary of how custodians make us more secure:

Previously, we might give Alice our crypto assets to hold. There were risks:

But "no worries", Alice has a custodian named Bob. Bob is dressed in a nice suit. He knows some politicians. And he drives a Porsche. "So you have nothing to worry about!". And look at all the benefits we get:
See - all problems are solved! All we have to worry about now is:
It's pretty simple. Before we had to trust Alice. Now we only have to trust Alice, Bob, and all the ways in which they communicate. Just think of how much more secure we are!

"On top of that", Bob assures us, "we're using a special wallet structure". Bob shows Alice a diagram. "We've broken the balance up and store it in lots of smaller wallets. That way", he assures her, "a thief can't take it all at once". And he points to a historic case where a large sum was taken "because it was stored in a single wallet... how stupid".
"Very early on, we used to have all the crypto in one wallet", he said, "and then one Christmas a hacker came and took it all. We call him the Grinch. Now we individually wrap each crypto and stick it under a binary search tree. The Grinch has never been back since."

"As well", Bob continues, "even if someone were to get in, we've got insurance. It covers all thefts and even coercion, collusion, and misplaced keys - only subject to the policy terms and conditions." And with that, he pulls out a phone-book sized contract and slams it on the desk with a thud. "Yep", he continues, "we're paying top dollar for one of the best policies in the country!"
"Can I read it?' Alice asks. "Sure," Bob says, "just as soon as our legal team is done with it. They're almost through the first chapter." He pauses, then continues. "And can you believe that sales guy Mike? He has the same year Porsche as me. I mean, what are the odds?"

"Do you use multi-sig?", Alice asks. "Absolutely!" Bob replies. "All our engineers are fully trained in multi-sig. Whenever we want to set up a new wallet, we generate 2 separate keys in an air-gapped process and store them in this proprietary system here. Look, it even requires the biometric signature from one of our team members to initiate any withdrawal." He demonstrates by pressing his thumb into the display. "We use a third-party cloud validation API to match the thumbprint and authorize each withdrawal. The keys are also backed up daily to an off-site third-party."
"Wow that's really impressive," Alice says, "but what if we need access for a withdrawal outside of office hours?" "Well that's no issue", Bob says, "just send us an email, call, or text message and we always have someone on staff to help out. Just another part of our strong commitment to all our customers!"

"What about Proof of Reserve?", Alice asks. "Of course", Bob replies, "though rather than publish any blockchain addresses or signed transaction, for privacy we just do a SHA256 refactoring of the inverse hash modulus for each UTXO nonce and combine the smart contract coefficient consensus in our hyperledger lightning node. But it's really simple to use." He pushes a button and a large green checkmark appears on a screen. "See - the algorithm ran through and reserves are proven."
"Wow", Alice says, "you really know your stuff! And that is easy to use! What about fiat balances?" "Yeah, we have an auditor too", Bob replies, "Been using him for a long time so we have quite a strong relationship going! We have special books we give him every year and he's very efficient! Checks the fiat, crypto, and everything all at once!"

"We used to have a nice offline multi-sig setup we've been using without issue for the past 5 years, but I think we'll move all our funds over to your facility," Alice says. "Awesome", Bob replies, "Thanks so much! This is perfect timing too - my Porsche got a dent on it this morning. We have the paperwork right over here." "Great!", Alice replies.
And with that, Alice gets out her pen and Bob gets the contract. "Don't worry", he says, "you can take your crypto-assets back anytime you like - just subject to our cancellation policy. Our annual management fees are also super low and we don't adjust them often".

How many holes have to exist for your funds to get stolen?
Just one.

Why are we taking a powerful offline multi-sig setup, widely used globally in hundreds of different/lacking regulatory environments with 0 breaches to date, and circumventing it by a demonstrably weak third party layer? And paying a great expense to do so?
If you go through the list of breaches in the past 2 years to highly credible organizations, you go through the list of major corporate frauds (only the ones we know about), you go through the list of all the times platforms have lost funds, you go through the list of times and ways that people have lost their crypto from identity theft, hot wallet exploits, extortion, etc... and then you go through this custodian with a fine-tooth comb and truly believe they have value to add far beyond what you could, sticking your funds in a wallet (or set of wallets) they control exclusively is the absolute worst possible way to take advantage of that security.

The best way to add security for crypto-assets is to make a stronger multi-sig. With one custodian, what you are doing is giving them your cryptocurrency and hoping they're honest, competent, and flawlessly secure. It's no different than storing it on a really secure exchange. Maybe the insurance will cover you. Didn't work for Bitpay in 2015. Didn't work for Yapizon in 2017. Insurance has never paid a claim in the entire history of cryptocurrency. But maybe you'll get lucky. Maybe your exact scenario will buck the trend and be what they're willing to cover. After the large deductible and hopefully without a long and expensive court battle.

And you want to advertise this increase in risk, the lapse of judgement, an accident waiting to happen, as though it's some kind of benefit to customers ("Free institutional-grade storage for your digital assets.")? And then some people are writing to the OSC that custodians should be mandatory for all funds on every exchange platform? That this somehow will make Canadians as a whole more secure or better protected compared with standard air-gapped multi-sig? On what planet?

Most of the problems in Canada stemmed from one thing - a lack of transparency. If Canadians had known what a joke Quadriga was - it wouldn't have grown to lose $400m from hard-working Canadians from coast to coast to coast. And Gerald Cotten would be in jail, not wherever he is now (at best, rotting peacefully). EZ-BTC and mister Dave Smilie would have been a tiny little scam to his friends, not a multi-million dollar fraud. Einstein would have got their act together or been shut down BEFORE losing millions and millions more in people's funds generously donated to criminals. MapleChange wouldn't have even been a thing. And maybe we'd know a little more about CoinTradeNewNote - like how much was lost in there. Almost all of the major losses with cryptocurrency exchanges involve deception with unbacked funds.
So it's great to see transparency reports from BitBuy and ShakePay where someone independently verified the backing. The only thing we don't have is:
It's not complicated to validate cryptocurrency assets. They need to exist, they need to be spendable, and they need to cover the total balances. There are plenty of credible people and firms across the country that have the capacity to reasonably perform this validation. Having more frequent checks by different, independent, parties who publish transparent reports is far more valuable than an annual check by a single "more credible/official" party who does the exact same basic checks and may or may not publish anything. Here's an example set of requirements that could be mandated:
There are ways to structure audits such that neither crypto assets nor customer information are ever put at risk, and both can still be properly validated and publicly verifiable. There are also ways to structure audits such that they are completely reasonable for small platforms and don't inhibit innovation in any way. By making the process as reasonable as possible, we can completely eliminate any reason/excuse that an honest platform would have for not being audited. That is arguable far more important than any incremental improvement we might get from mandating "the best of the best" accountants. Right now we have nothing mandated and tons of Canadians using offshore exchanges with no oversight whatsoever.

Transparency does not prove crypto assets are safe. CoinTradeNewNote, Flexcoin ($600k), and Canadian Bitcoins ($100k) are examples where crypto-assets were breached from platforms in Canada. All of them were online wallets and used no multi-sig as far as any records show. This is consistent with what we see globally - air-gapped multi-sig wallets have an impeccable record, while other schemes tend to suffer breach after breach. We don't actually know how much CoinTrader lost because there was no visibility. Rather than publishing details of what happened, the co-founder of CoinTrader silently moved on to found another platform - the "most trusted way to buy and sell crypto" - a site that has no information whatsoever (that I could find) on the storage practices and a FAQ advising that “[t]rading cryptocurrency is completely safe” and that having your own wallet is “entirely up to you! You can certainly keep cryptocurrency, or fiat, or both, on the app.” Doesn't sound like much was learned here, which is really sad to see.
It's not that complicated or unreasonable to set up a proper hardware wallet. Multi-sig can be learned in a single course. Something the equivalent complexity of a driver's license test could prevent all the cold storage exploits we've seen to date - even globally. Platform operators have a key advantage in detecting and preventing fraud - they know their customers far better than any custodian ever would. The best job that custodians can do is to find high integrity individuals and train them to form even better wallet signatories. Rather than mandating that all platforms expose themselves to arbitrary third party risks, regulations should center around ensuring that all signatories are background-checked, properly trained, and using proper procedures. We also need to make sure that signatories are empowered with rights and responsibilities to reject and report fraud. They need to know that they can safely challenge and delay a transaction - even if it turns out they made a mistake. We need to have an environment where mistakes are brought to the surface and dealt with. Not one where firms and people feel the need to hide what happened. In addition to a knowledge-based test, an auditor can privately interview each signatory to make sure they're not in coercive situations, and we should make sure they can freely and anonymously report any issues without threat of retaliation.
A proper multi-sig has each signature held by a separate person and is governed by policies and mutual decisions instead of a hierarchy. It includes at least one redundant signature. For best results, 3of4, 3of5, 3of6, 4of5, 4of6, 4of7, 5of6, or 5of7.

History has demonstrated over and over again the risk of hot wallets even to highly credible organizations. Nonetheless, many platforms have hot wallets for convenience. While such losses are generally compensated by platforms without issue (for example Poloniex, Bitstamp, Bitfinex, Gatecoin, Coincheck, Bithumb, Zaif, CoinBene, Binance, Bitrue, Bitpoint, Upbit, VinDAX, and now KuCoin), the public tends to focus more on cases that didn't end well. Regardless of what systems are employed, there is always some level of risk. For that reason, most members of the public would prefer to see third party insurance.
Rather than trying to convince third party profit-seekers to provide comprehensive insurance and then relying on an expensive and slow legal system to enforce against whatever legal loopholes they manage to find each and every time something goes wrong, insurance could be run through multiple exchange operators and regulators, with the shared interest of having a reputable industry, keeping costs down, and taking care of Canadians. For example, a 4 of 7 multi-sig insurance fund held between 5 independent exchange operators and 2 regulatory bodies. All Canadian exchanges could pay premiums at a set rate based on their needed coverage, with a higher price paid for hot wallet coverage (anything not an air-gapped multi-sig cold wallet). Such a model would be much cheaper to manage, offer better coverage, and be much more reliable to payout when needed. The kind of coverage you could have under this model is unheard of. You could even create something like the CDIC to protect Canadians who get their trading accounts hacked if they can sufficiently prove the loss is legitimate. In cases of fraud, gross negligence, or insolvency, the fund can be used to pay affected users directly (utilizing the last transparent balance report in the worst case), something which private insurance would never touch. While it's recommended to have official policies for coverage, a model where members vote would fully cover edge cases. (Could be similar to the Supreme Court where justices vote based on case law.)
Such a model could fully protect all Canadians across all platforms. You can have a fiat coverage governed by legal agreements, and crypto-asset coverage governed by both multi-sig and legal agreements. It could be practical, affordable, and inclusive.

Now, we are at a crossroads. We can happily give up our freedom, our innovation, and our money. We can pay hefty expenses to auditors, lawyers, and regulators year after year (and make no mistake - this cost will grow to many millions or even billions as the industry grows - and it will be borne by all Canadians on every platform because platforms are not going to eat up these costs at a loss). We can make it nearly impossible for any new platform to enter the marketplace, forcing Canadians to use the same stagnant platforms year after year. We can centralize and consolidate the entire industry into 2 or 3 big players and have everyone else fail (possibly to heavy losses of users of those platforms). And when a flawed security model doesn't work and gets breached, we can make it even more complicated with even more people in suits making big money doing the job that blockchain was supposed to do in the first place. We can build a system which is so intertwined and dependent on big government, traditional finance, and central bankers that it's future depends entirely on that of the fiat system, of fractional banking, and of government bail-outs. If we choose this path, as history has shown us over and over again, we can not go back, save for revolution. Our children and grandchildren will still be paying the consequences of what we decided today.
Or, we can find solutions that work. We can maintain an open and innovative environment while making the adjustments we need to make to fully protect Canadian investors and cryptocurrency users, giving easy and affordable access to cryptocurrency for all Canadians on the platform of their choice, and creating an environment in which entrepreneurs and problem solvers can bring those solutions forward easily. None of the above precludes innovation in any way, or adds any unreasonable cost - and these three policies would demonstrably eliminate or resolve all 109 historic cases as studied here - that's every single case researched so far going back to 2011. It includes every loss that was studied so far not just in Canada but globally as well.
Unfortunately, finding answers is the least challenging part. Far more challenging is to get platform operators and regulators to agree on anything. My last post got no response whatsoever, and while the OSC has told me they're happy for industry feedback, I believe my opinion alone is fairly meaningless. This takes the whole community working together to solve. So please let me know your thoughts. Please take the time to upvote and share this with people. Please - let's get this solved and not leave it up to other people to do.

Facts/background/sources (skip if you like):



Thoughts?
submitted by azoundria2 to QuadrigaInitiative [link] [comments]

RiB Newsletter #16 – Secure Enclaves à la Crab

For the last few months we’ve been following new zero-knowledge proof projects in Rust. This month, with Secret Network upgrading their mainnet with secret contracts, it seems like a good opportunity to explore Rust blockchains that are using a completely different privacy-preserving technology: secure enclaves.
Secure enclaves are processes whose environment is protected from inspection by other processes, even the kernel, by special hardware. This protection particularly involves the encryption of a process’s memory. Software that wants to compute in secret can put those computations inside a secure enclave and, if everything works as expected, neither a local user, nor the hosting provider, can snoop on the computations being performed. The most notable implementation of secure enclaves is Intel’s SGX (Secure Guard Extensions).
Secure enclaves are an attractive way to perform private computation primarily because they don’t impose any limitations on what can be computed — code that runs inside SGX is more-or-less just regular x86 code, just running inside a special environment. But depending on SGX for privacy does have some special risks: software that runs in an SGX enclave must be signed (if transitively) by Intel’s own cryptographic keys, which means that Intel must approve of any software running in SGX, that Intel can revoke permission to use SGX, and that there is a risk of the signing keys being compromised; and it’s not obvious that secure enclaves are actually secure, there have already been a number of attacks against SGX. Regardless, as of now, hardware enclaves provide security features that aren’t feasible any other way.
There are two prominent Rust blockchains relying on SGX:
Outside of the blockchain world there are some other Rust projects using SGX, the most notable being:
Whether it’s secure enclaves or zk-SNARKs, Rust blockchains are walking the bleeding edge of privacy tech.
In unrelated RiB news, we recently received two donations,
Thanks so much to our anonymous donors. We don’t often receive donations, so this was a nice surprise! We intend to put all monetary contributions to use funding events or new contributors, and we’ll let you know what we do with the funds when we spend them.

Project Spotlight

Each month we like to shine a light on a notable Rust blockchain project. This month that project is…
Aleo.
Aleo is a zero-knowledge blockchain, with its own zero-knowledge programming language, Leo.
We don’t have a lot to say about it, but we think it looks cool. We hope they blog more.

Interesting Things

News

Blog Posts

Papers

Projects


Read more: https://rustinblockchain.org/newsletters/2020-09-30-secure-enclaves-a-la-crab/
submitted by Aimeedeer to rust [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to ethereum [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to privacycoins [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to CryptoCurrencies [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to ethtrader [link] [comments]

An Insight Into Bitcoin Improvement Proposal (BIP)

While Bitcoin is the most famous and valuable cryptocurrency, its blockchain faces some challenges. In order to ensure the constant dominance of the currency in the market, the Bitcoin Improvement Proposal (BIP) was introduced. While most BIPs have different levels of potential for positive impact on Bitcoin blockchain, some of them turned out to be much more successful than others.

What is BIP?

Bitcoin is considered the first cryptocurrency and still remains the most successful crypto-project, but it also has its drawbacks. And in order to surpass it, as well as to occupy its niche in the digital world, innovators have created many new currencies, each of which has its own blockchain, designed to provide functions that are not available in Bitcoin. Eventually, one of these new currencies could potentially knock Bitcoin out of the first place.
That’s why the work on the Bitcoin Improvement Proposal began. BIP is a document where developers can submit a recommendation to fix a network problem. For example, after the introduction and implementation of BIP 141, also known as Segregated Witness (SegWit), the transaction rate on the Bitcoin network has increased, and commission fees have significantly decreased.
There are three varieties of BIP:

Bitcoin Lightning Network

The Lightning Network is a BIP proposal introduced in 2015 by Joseph Poon and Thaddeus Dryja. It aims to make Bitcoin scalable with the help of instant payments that are performed outside the network. These external channels form real Bitcoin transactions with the use of standard scripts that allow transferring funds without risk.
The Lightning network came into force thanks to the introduction of wallets with many signatures, where the parties can conduct an infinite number of transactions without having to store all the details on the blockchain. The only information recorded on the blockchain is the number of Bitcoins contained in the wallet and the percentage of contributions of the parties involved.
In addition to enabling instant transactions, the update also provides other benefits for the Bitcoin chain. For example, registration for micropayments, as well as cross-chain payments. Moreover, the update also promotes the implementation of the functionality of smart contracts on top of the blockchain.

MAST technology

MAST stands for Merkelized Abstract Syntax Tree, a technology that uses the ideas of the Merkle tree and the abstract syntax tree. This is a cryptographic tool that allows you to add large volumes of the hash to the data associated with transactions in the Bitcoin chain, due to their layout.
Three BIPs aim to introduce MAST into the Bitcoin network. The first is BIP 114, created by Johnson Lau, the developer of the Bitcoin core. The proposal shows how to increase network efficiency by introducing a new scenario, which he calls a merkelized scenario. The scenario reduces the need for large amounts of transaction data while maintaining greater privacy.
BIP 116 and BIP 117 were proposed by Bitcoin Core developer Mark Friedenbach and are intended to support MAST in a joint implementation. In BIP 116, he outlines the operation code, which allowed validation of the data without revealing the entire set. BIP 117 is called the Tail Call semantics, and in combination with the first, it led to a generalized form of MAST. The difference between the offers of Friedenbach and Lau is that the first supports all the scenarios that are currently used on the Bitcoin network, and the second supports only native SegWit.
The introduction of MAST has led to increased privacy, increased transaction speed, and the ability to include complex data sets, such as smart contracts. Besides, MAST allowed the Bitcoin network to process a much larger volume of transactions and, thereby, increased its scalability.

How many BIPs are there?

Since absolutely any developer can submit the idea of improving the network to the community, more than 300 of these ideas have already been accumulated, and not all of them have been and will be implemented in Bitcoin.
Keep up with the news of the crypto world at CoinJoy.io Follow us on Twitter and Medium. Subscribe to our YouTube channel. Join our Telegram channel. For any inquiries mail us at [[email protected]](mailto:[email protected]).
submitted by CoinjoyAssistant to Bitcoin [link] [comments]

Proof Of Work Explained

Proof Of Work Explained
https://preview.redd.it/hl80wdx61j451.png?width=1200&format=png&auto=webp&s=c80b21c53ae45c6f7d618f097bc705a1d8aaa88f
A proof-of-work (PoW) system (or protocol, or function) is a consensus mechanism that was first invented by Cynthia Dwork and Moni Naor as presented in a 1993 journal article. In 1999, it was officially adopted in a paper by Markus Jakobsson and Ari Juels and they named it as "proof of work".
It was developed as a way to prevent denial of service attacks and other service abuse (such as spam on a network). This is the most widely used consensus algorithm being used by many cryptocurrencies such as Bitcoin and Ethereum.
How does it work?
In this method, a group of users competes against each other to find the solution to a complex mathematical puzzle. Any user who successfully finds the solution would then broadcast the block to the network for verifications. Once the users verified the solution, the block then moves to confirm the state.
The blockchain network consists of numerous sets of decentralized nodes. These nodes act as admin or miners which are responsible for adding new blocks into the blockchain. The miner instantly and randomly selects a number which is combined with the data present in the block. To find a correct solution, the miners need to select a valid random number so that the newly generated block can be added to the main chain. It pays a reward to the miner node for finding the solution.
The block then passed through a hash function to generate output which matches all input/output criteria. Once the result is found, other nodes in the network verify and validate the outcome. Every new block holds the hash of the preceding block. This forms a chain of blocks. Together, they store information within the network. Changing a block requires a new block containing the same predecessor. It is almost impossible to regenerate all successors and change their data. This protects the blockchain from tampering.
What is Hash Function?
A hash function is a function that is used to map data of any length to some fixed-size values. The result or outcome of a hash function is known as hash values, hash codes, digests, or simply hashes.
https://preview.redd.it/011tfl8c1j451.png?width=851&format=png&auto=webp&s=ca9c2adecbc0b14129a9b2eea3c2f0fd596edd29
The hash method is quite secure, any slight change in input will result in a different output, which further results in discarded by network participants. The hash function generates the same length of output data to that of input data. It is a one-way function i.e the function cannot be reversed to get the original data back. One can only perform checks to validate the output data with the original data.
Implementations
Nowadays, Proof-of-Work is been used in a lot of cryptocurrencies. But it was first implemented in Bitcoin after which it becomes so popular that it was adopted by several other cryptocurrencies. Bitcoin uses the puzzle Hashcash, the complexity of a puzzle is based upon the total power of the network. On average, it took approximately 10 min to block formation. Litecoin, a Bitcoin-based cryptocurrency is having a similar system. Ethereum also implemented this same protocol.
Types of PoW
Proof-of-work protocols can be categorized into two parts:-
· Challenge-response
This protocol creates a direct link between the requester (client) and the provider (server).
In this method, the requester needs to find the solution to a challenge that the server has given. The solution is then validated by the provider for authentication.
The provider chooses the challenge on the spot. Hence, its difficulty can be adapted to its current load. If the challenge-response protocol has a known solution or is known to exist within a bounded search space, then the work on the requester side may be bounded.
https://preview.redd.it/ij967dof1j451.png?width=737&format=png&auto=webp&s=12670c2124fc27b0f988bb4a1daa66baf99b4e27
Source-wiki
· Solution–verification
These protocols do not have any such prior link between the sender and the receiver. The client, self-imposed a problem and solve it. It then sends the solution to the server to check both the problem choice and the outcome. Like Hashcash these schemes are also based on unbounded probabilistic iterative procedures.
https://preview.redd.it/gfobj9xg1j451.png?width=740&format=png&auto=webp&s=2291fd6b87e84395f8a4364267f16f577b5f1832
Source-wiki
These two methods generally based on the following three techniques:-
CPU-bound
This technique depends upon the speed of the processor. The higher the processor power greater will be the computation.
Memory-bound
This technique utilizes the main memory accesses (either latency or bandwidth) in computation speed.
Network-bound
In this technique, the client must perform a few computations and wait to receive some tokens from remote servers.
List of proof-of-work functions
Here is a list of known proof-of-work functions:-
o Integer square root modulo a large prime
o Weaken Fiat–Shamir signatures`2
o Ong–Schnorr–Shamir signature is broken by Pollard
o Partial hash inversion
o Hash sequences
o Puzzles
o Diffie–Hellman–based puzzle
o Moderate
o Mbound
o Hokkaido
o Cuckoo Cycle
o Merkle tree-based
o Guided tour puzzle protocol
A successful attack on a blockchain network requires a lot of computational power and a lot of time to do the calculations. Proof of Work makes hacks inefficient since the cost incurred would be greater than the potential rewards for attacking the network. Miners are also incentivized not to cheat.
It is still considered as one of the most popular methods of reaching consensus in blockchains. Though it may not be the most efficient solution due to high energy extensive usage. But this is why it guarantees the security of the network.
Due to Proof of work, it is quite impossible to alter any aspect of the blockchain, since any such changes would require re-mining all those subsequent blocks. It is also difficult for a user to take control over the network computing power since the process requires high energy thus making these hash functions expensive.
submitted by RumaDas to u/RumaDas [link] [comments]

An Insight Into Bitcoin Improvement Proposal (BIP)

While Bitcoin is the most famous and valuable cryptocurrency, its blockchain faces some challenges. In order to ensure the constant dominance of the currency in the market, the Bitcoin Improvement Proposal (BIP) was introduced. While most BIPs have different levels of potential for positive impact on Bitcoin blockchain, some of them turned out to be much more successful than others.

What is BIP?

Bitcoin is considered the first cryptocurrency and still remains the most successful crypto-project, but it also has its drawbacks. And in order to surpass it, as well as to occupy its niche in the digital world, innovators have created many new currencies, each of which has its own blockchain, designed to provide functions that are not available in Bitcoin. Eventually, one of these new currencies could potentially knock Bitcoin out of the first place.
That’s why the work on the Bitcoin Improvement Proposal began. BIP is a document where developers can submit a recommendation to fix a network problem. For example, after the introduction and implementation of BIP 141, also known as Segregated Witness (SegWit), the transaction rate on the Bitcoin network has increased, and commission fees have significantly decreased.
There are three varieties of BIP:

Bitcoin Lightning Network

The Lightning Network is a BIP proposal introduced in 2015 by Joseph Poon and Thaddeus Dryja. It aims to make Bitcoin scalable with the help of instant payments that are performed outside the network. These external channels form real Bitcoin transactions with the use of standard scripts that allow transferring funds without risk.
The Lightning network came into force thanks to the introduction of wallets with many signatures, where the parties can conduct an infinite number of transactions without having to store all the details on the blockchain. The only information recorded on the blockchain is the number of Bitcoins contained in the wallet and the percentage of contributions of the parties involved.
In addition to enabling instant transactions, the update also provides other benefits for the Bitcoin chain. For example, registration for micropayments, as well as cross-chain payments. Moreover, the update also promotes the implementation of the functionality of smart contracts on top of the blockchain.

MAST technology

MAST stands for Merkelized Abstract Syntax Tree, a technology that uses the ideas of the Merkle tree and the abstract syntax tree. This is a cryptographic tool that allows you to add large volumes of the hash to the data associated with transactions in the Bitcoin chain, due to their layout.
Three BIPs aim to introduce MAST into the Bitcoin network. The first is BIP 114, created by Johnson Lau, the developer of the Bitcoin core. The proposal shows how to increase network efficiency by introducing a new scenario, which he calls a merkelized scenario. The scenario reduces the need for large amounts of transaction data while maintaining greater privacy.
BIP 116 and BIP 117 were proposed by Bitcoin Core developer Mark Friedenbach and are intended to support MAST in a joint implementation. In BIP 116, he outlines the operation code, which allowed validation of the data without revealing the entire set. BIP 117 is called the Tail Call semantics, and in combination with the first, it led to a generalized form of MAST. The difference between the offers of Friedenbach and Lau is that the first supports all the scenarios that are currently used on the Bitcoin network, and the second supports only native SegWit.
The introduction of MAST has led to increased privacy, increased transaction speed, and the ability to include complex data sets, such as smart contracts. Besides, MAST allowed the Bitcoin network to process a much larger volume of transactions and, thereby, increased its scalability.

How many BIPs are there?

Since absolutely any developer can submit the idea of improving the network to the community, more than 300 of these ideas have already been accumulated, and not all of them have been and will be implemented in Bitcoin.
Keep up with the news of the crypto world at CoinJoy.io Follow us on Twitter and Medium. Subscribe to our YouTube channel. Join our Telegram channel. For any inquiries mail us at [[email protected]](mailto:[email protected]).
submitted by CoinjoyAssistant to u/CoinjoyAssistant [link] [comments]

For devs and advanced users that are still in the dark: Read this to get redpilled about why Bitcoin (SV) is the real Bitcoin

This post by cryptorebel is a great intro for newbies. Here is a continuation for a technical audience. I'll be making edits for readability and maybe even add more content.
The short explanation of why BSV is the real Bitcoin is that it implements the original L1 scripting language, and removes hacks like p2sh. It also removes the block size limit, and yes that leads to a small number of huge nodes. It might not be the system you wanted. Nodes are miners.
The key thing to understand about the UTXO architecture is that it is maximally "sharded" by default. Logically dependent transactions may require linear span to construct, but they can be validated in sublinear span (actually polylogarithmic expected span). Constructing dependent transactions happens out-of-band in any case.
The fact that transactions in a block are merkelized is an obvious sign that Bitcoin was designed for big blocks. But merkle trees are only half the story. UTXOs are essentially hash-addressed stateful continuation snapshots which can also be "merged" (validated) in a tree.
I won't even bother talking about how broken Lightning Network is. Of all the L2 scaling solutions that could have been used with small block sizes, it's almost unbelievable how many bad choices they've made. We should be kind to them and assume it was deliberate sabotage rather than insulting their intelligence.
Segwit is also outside the scope of this post.
However I will briefly hate on p2sh. Imagine seeing a stunted L1 script language, and deciding that the best way to implement multisigs was a soft-fork patch in the form of p2sh. If the intent was truly backwards-compatability with old clients, then by that logic all segwit and p2sh addresses are supposed to only be protected by transient rules outside of the protocol. Explain that to your custody clients.
As far as Bitcoin Cash goes, I was in the camp of "there's still time to save BCH" until not too long ago. Unfortunately the galaxy brains behind BCH have doubled down on their mistakes. Again, it is kinder to assume deliberate sabotage. (As an aside, the fact that they didn't embrace the name "bcash" when it was used to attack them shows how unprepared they are when the real psyops start to hit. Or, again, that the saboteurs controlled the entire back-and-forth.)
The one useful thing that came out of BCH is some progress on L1 apps based on covenants, but the issue is that they are not taking care to ensure every change maintains the asymptotic validation complexity of bitcoin's UTXO.
Besides that, The BCH devs missed something big. So did I.
It's possible to load the entire transaction onto the stack without adding any new opcodes. Read this post for a quick intro on how transaction meta-evaluation leads to stateful smart contract capabilities. Note that it was written before I understood how it was possible in Bitcoin, but the concept is the same. I've switching to developing a language that abstracts this behavior and compiles to bitcoin's L1. (Please don't "told you so" at me if you just blindly trusted nChain but still can't explain how it's done.)
It is true that this does not allow exactly the same class of L1 applications as Ethereum. It only allows those than can be made parallel, those that can delegate synchronization to "userspace". It forces you to be scalable, to process bottlenecks out-of-band at a per-application level.
Now, some of the more diehard supporters might say that Satoshi knew this was possible and meant for it to be this way, but honestly I don't believe that. nChain says they discovered the technique 'several years ago'. OP_PUSH_TX would have been a very simple opcode to include, and it does not change any aspect of validation in any way. The entire transaction is already in the L1 evaluation context for the purpose of checksig, it truly changes nothing.
But here's the thing: it doesn't matter if this was a happy accident. What matters is that it works. It is far more important to keep the continuity of the original protocol spec than to keep making optimizations at the protocol level. In a concatenative language like bitcoin script, optimized clients can recognize "checksig trick phrases" regardless of their location in the script, and treat them like a simple opcode. Script size is not a constraint when you allow the protocol to scale as designed. Think of it as precompiles in EVM.
Now let's address Ethereum. V. Buterin recently wrote a great piece about the concept of credible neutrality. The only way for a blockchain system to achieve credible neutrality and long-term decentralization of power is to lock down the protocol rules. The thing that caused Ethereum to succeed was the yellow paper. Ethereum has outperformed every other smart contract platform because the EVM has clear semantics with many implementations, so people can invest time and resources into applications built on it. The EVM is apolitical, the EVM spec (fixed at any particular version) is truly decentralized. Team Ethereum can plausibly maintain credibility and neutrality as long as they make progress towards the "Serenity" vision they outlined years ago. Unfortunately they have already placed themselves in a precarious position by picking and choosing which catastrophes they intervene on at the protocol level.
But those are social and political issues. The major technical issue facing the EVM is that it is inherently sequential. It does not have the key property that transactions that occur "later" in the block can be validated before the transactions they depend on are validated. Sharding will hit a wall faster than you can say "O(n/64) is O(n)". Ethereum will get a lot of mileage out of L2, but the fundamental overhead of synchronization in L1 will never go away. The best case scaling scenario for ETH is an L2 system with sublinear validation properties like UTXO. If the economic activity on that L2 system grows larger than that of the L1 chain, the system loses key security properties. Ethereum is sequential by default with parallelism enabled by L2, while Bitcoin is parallel by default with synchronization forced into L2.
Finally, what about CSW? I expect soon we will see a lot of people shouting, "it doesn't matter who Satoshi is!", and they're right. The blockchain doesn't care if CSW is Satoshi or not. It really seems like many people's mental model is "Bitcoin (BSV) scales and has smart contracts if CSW==Satoshi". Sorry, but UTXO scales either way. The checksig trick works either way.
Coin Woke.
submitted by -mr-word- to bitcoincashSV [link] [comments]

Bitcoin (BTC)A Peer-to-Peer Electronic Cash System.

Bitcoin (BTC)A Peer-to-Peer Electronic Cash System.
  • Bitcoin (BTC) is a peer-to-peer cryptocurrency that aims to function as a means of exchange that is independent of any central authority. BTC can be transferred electronically in a secure, verifiable, and immutable way.
  • Launched in 2009, BTC is the first virtual currency to solve the double-spending issue by timestamping transactions before broadcasting them to all of the nodes in the Bitcoin network. The Bitcoin Protocol offered a solution to the Byzantine Generals’ Problem with a blockchain network structure, a notion first created by Stuart Haber and W. Scott Stornetta in 1991.
  • Bitcoin’s whitepaper was published pseudonymously in 2008 by an individual, or a group, with the pseudonym “Satoshi Nakamoto”, whose underlying identity has still not been verified.
  • The Bitcoin protocol uses an SHA-256d-based Proof-of-Work (PoW) algorithm to reach network consensus. Its network has a target block time of 10 minutes and a maximum supply of 21 million tokens, with a decaying token emission rate. To prevent fluctuation of the block time, the network’s block difficulty is re-adjusted through an algorithm based on the past 2016 block times.
  • With a block size limit capped at 1 megabyte, the Bitcoin Protocol has supported both the Lightning Network, a second-layer infrastructure for payment channels, and Segregated Witness, a soft-fork to increase the number of transactions on a block, as solutions to network scalability.

https://preview.redd.it/s2gmpmeze3151.png?width=256&format=png&auto=webp&s=9759910dd3c4a15b83f55b827d1899fb2fdd3de1

1. What is Bitcoin (BTC)?

  • Bitcoin is a peer-to-peer cryptocurrency that aims to function as a means of exchange and is independent of any central authority. Bitcoins are transferred electronically in a secure, verifiable, and immutable way.
  • Network validators, whom are often referred to as miners, participate in the SHA-256d-based Proof-of-Work consensus mechanism to determine the next global state of the blockchain.
  • The Bitcoin protocol has a target block time of 10 minutes, and a maximum supply of 21 million tokens. The only way new bitcoins can be produced is when a block producer generates a new valid block.
  • The protocol has a token emission rate that halves every 210,000 blocks, or approximately every 4 years.
  • Unlike public blockchain infrastructures supporting the development of decentralized applications (Ethereum), the Bitcoin protocol is primarily used only for payments, and has only very limited support for smart contract-like functionalities (Bitcoin “Script” is mostly used to create certain conditions before bitcoins are used to be spent).

2. Bitcoin’s core features

For a more beginner’s introduction to Bitcoin, please visit Binance Academy’s guide to Bitcoin.

Unspent Transaction Output (UTXO) model

A UTXO transaction works like cash payment between two parties: Alice gives money to Bob and receives change (i.e., unspent amount). In comparison, blockchains like Ethereum rely on the account model.
https://preview.redd.it/t1j6anf8f3151.png?width=1601&format=png&auto=webp&s=33bd141d8f2136a6f32739c8cdc7aae2e04cbc47

Nakamoto consensus

In the Bitcoin network, anyone can join the network and become a bookkeeping service provider i.e., a validator. All validators are allowed in the race to become the block producer for the next block, yet only the first to complete a computationally heavy task will win. This feature is called Proof of Work (PoW).
The probability of any single validator to finish the task first is equal to the percentage of the total network computation power, or hash power, the validator has. For instance, a validator with 5% of the total network computation power will have a 5% chance of completing the task first, and therefore becoming the next block producer.
Since anyone can join the race, competition is prone to increase. In the early days, Bitcoin mining was mostly done by personal computer CPUs.
As of today, Bitcoin validators, or miners, have opted for dedicated and more powerful devices such as machines based on Application-Specific Integrated Circuit (“ASIC”).
Proof of Work secures the network as block producers must have spent resources external to the network (i.e., money to pay electricity), and can provide proof to other participants that they did so.
With various miners competing for block rewards, it becomes difficult for one single malicious party to gain network majority (defined as more than 51% of the network’s hash power in the Nakamoto consensus mechanism). The ability to rearrange transactions via 51% attacks indicates another feature of the Nakamoto consensus: the finality of transactions is only probabilistic.
Once a block is produced, it is then propagated by the block producer to all other validators to check on the validity of all transactions in that block. The block producer will receive rewards in the network’s native currency (i.e., bitcoin) as all validators approve the block and update their ledgers.

The blockchain

Block production

The Bitcoin protocol utilizes the Merkle tree data structure in order to organize hashes of numerous individual transactions into each block. This concept is named after Ralph Merkle, who patented it in 1979.
With the use of a Merkle tree, though each block might contain thousands of transactions, it will have the ability to combine all of their hashes and condense them into one, allowing efficient and secure verification of this group of transactions. This single hash called is a Merkle root, which is stored in the Block Header of a block. The Block Header also stores other meta information of a block, such as a hash of the previous Block Header, which enables blocks to be associated in a chain-like structure (hence the name “blockchain”).
An illustration of block production in the Bitcoin Protocol is demonstrated below.

https://preview.redd.it/m6texxicf3151.png?width=1591&format=png&auto=webp&s=f4253304912ed8370948b9c524e08fef28f1c78d

Block time and mining difficulty

Block time is the period required to create the next block in a network. As mentioned above, the node who solves the computationally intensive task will be allowed to produce the next block. Therefore, block time is directly correlated to the amount of time it takes for a node to find a solution to the task. The Bitcoin protocol sets a target block time of 10 minutes, and attempts to achieve this by introducing a variable named mining difficulty.
Mining difficulty refers to how difficult it is for the node to solve the computationally intensive task. If the network sets a high difficulty for the task, while miners have low computational power, which is often referred to as “hashrate”, it would statistically take longer for the nodes to get an answer for the task. If the difficulty is low, but miners have rather strong computational power, statistically, some nodes will be able to solve the task quickly.
Therefore, the 10 minute target block time is achieved by constantly and automatically adjusting the mining difficulty according to how much computational power there is amongst the nodes. The average block time of the network is evaluated after a certain number of blocks, and if it is greater than the expected block time, the difficulty level will decrease; if it is less than the expected block time, the difficulty level will increase.

What are orphan blocks?

In a PoW blockchain network, if the block time is too low, it would increase the likelihood of nodes producingorphan blocks, for which they would receive no reward. Orphan blocks are produced by nodes who solved the task but did not broadcast their results to the whole network the quickest due to network latency.
It takes time for a message to travel through a network, and it is entirely possible for 2 nodes to complete the task and start to broadcast their results to the network at roughly the same time, while one’s messages are received by all other nodes earlier as the node has low latency.
Imagine there is a network latency of 1 minute and a target block time of 2 minutes. A node could solve the task in around 1 minute but his message would take 1 minute to reach the rest of the nodes that are still working on the solution. While his message travels through the network, all the work done by all other nodes during that 1 minute, even if these nodes also complete the task, would go to waste. In this case, 50% of the computational power contributed to the network is wasted.
The percentage of wasted computational power would proportionally decrease if the mining difficulty were higher, as it would statistically take longer for miners to complete the task. In other words, if the mining difficulty, and therefore targeted block time is low, miners with powerful and often centralized mining facilities would get a higher chance of becoming the block producer, while the participation of weaker miners would become in vain. This introduces possible centralization and weakens the overall security of the network.
However, given a limited amount of transactions that can be stored in a block, making the block time too longwould decrease the number of transactions the network can process per second, negatively affecting network scalability.

3. Bitcoin’s additional features

Segregated Witness (SegWit)

Segregated Witness, often abbreviated as SegWit, is a protocol upgrade proposal that went live in August 2017.
SegWit separates witness signatures from transaction-related data. Witness signatures in legacy Bitcoin blocks often take more than 50% of the block size. By removing witness signatures from the transaction block, this protocol upgrade effectively increases the number of transactions that can be stored in a single block, enabling the network to handle more transactions per second. As a result, SegWit increases the scalability of Nakamoto consensus-based blockchain networks like Bitcoin and Litecoin.
SegWit also makes transactions cheaper. Since transaction fees are derived from how much data is being processed by the block producer, the more transactions that can be stored in a 1MB block, the cheaper individual transactions become.
https://preview.redd.it/depya70mf3151.png?width=1601&format=png&auto=webp&s=a6499aa2131fbf347f8ffd812930b2f7d66be48e
The legacy Bitcoin block has a block size limit of 1 megabyte, and any change on the block size would require a network hard-fork. On August 1st 2017, the first hard-fork occurred, leading to the creation of Bitcoin Cash (“BCH”), which introduced an 8 megabyte block size limit.
Conversely, Segregated Witness was a soft-fork: it never changed the transaction block size limit of the network. Instead, it added an extended block with an upper limit of 3 megabytes, which contains solely witness signatures, to the 1 megabyte block that contains only transaction data. This new block type can be processed even by nodes that have not completed the SegWit protocol upgrade.
Furthermore, the separation of witness signatures from transaction data solves the malleability issue with the original Bitcoin protocol. Without Segregated Witness, these signatures could be altered before the block is validated by miners. Indeed, alterations can be done in such a way that if the system does a mathematical check, the signature would still be valid. However, since the values in the signature are changed, the two signatures would create vastly different hash values.
For instance, if a witness signature states “6,” it has a mathematical value of 6, and would create a hash value of 12345. However, if the witness signature were changed to “06”, it would maintain a mathematical value of 6 while creating a (faulty) hash value of 67890.
Since the mathematical values are the same, the altered signature remains a valid signature. This would create a bookkeeping issue, as transactions in Nakamoto consensus-based blockchain networks are documented with these hash values, or transaction IDs. Effectively, one can alter a transaction ID to a new one, and the new ID can still be valid.
This can create many issues, as illustrated in the below example:
  1. Alice sends Bob 1 BTC, and Bob sends Merchant Carol this 1 BTC for some goods.
  2. Bob sends Carols this 1 BTC, while the transaction from Alice to Bob is not yet validated. Carol sees this incoming transaction of 1 BTC to him, and immediately ships goods to B.
  3. At the moment, the transaction from Alice to Bob is still not confirmed by the network, and Bob can change the witness signature, therefore changing this transaction ID from 12345 to 67890.
  4. Now Carol will not receive his 1 BTC, as the network looks for transaction 12345 to ensure that Bob’s wallet balance is valid.
  5. As this particular transaction ID changed from 12345 to 67890, the transaction from Bob to Carol will fail, and Bob will get his goods while still holding his BTC.
With the Segregated Witness upgrade, such instances can not happen again. This is because the witness signatures are moved outside of the transaction block into an extended block, and altering the witness signature won’t affect the transaction ID.
Since the transaction malleability issue is fixed, Segregated Witness also enables the proper functioning of second-layer scalability solutions on the Bitcoin protocol, such as the Lightning Network.

Lightning Network

Lightning Network is a second-layer micropayment solution for scalability.
Specifically, Lightning Network aims to enable near-instant and low-cost payments between merchants and customers that wish to use bitcoins.
Lightning Network was conceptualized in a whitepaper by Joseph Poon and Thaddeus Dryja in 2015. Since then, it has been implemented by multiple companies. The most prominent of them include Blockstream, Lightning Labs, and ACINQ.
A list of curated resources relevant to Lightning Network can be found here.
In the Lightning Network, if a customer wishes to transact with a merchant, both of them need to open a payment channel, which operates off the Bitcoin blockchain (i.e., off-chain vs. on-chain). None of the transaction details from this payment channel are recorded on the blockchain, and only when the channel is closed will the end result of both party’s wallet balances be updated to the blockchain. The blockchain only serves as a settlement layer for Lightning transactions.
Since all transactions done via the payment channel are conducted independently of the Nakamoto consensus, both parties involved in transactions do not need to wait for network confirmation on transactions. Instead, transacting parties would pay transaction fees to Bitcoin miners only when they decide to close the channel.
https://preview.redd.it/cy56icarf3151.png?width=1601&format=png&auto=webp&s=b239a63c6a87ec6cc1b18ce2cbd0355f8831c3a8
One limitation to the Lightning Network is that it requires a person to be online to receive transactions attributing towards him. Another limitation in user experience could be that one needs to lock up some funds every time he wishes to open a payment channel, and is only able to use that fund within the channel.
However, this does not mean he needs to create new channels every time he wishes to transact with a different person on the Lightning Network. If Alice wants to send money to Carol, but they do not have a payment channel open, they can ask Bob, who has payment channels open to both Alice and Carol, to help make that transaction. Alice will be able to send funds to Bob, and Bob to Carol. Hence, the number of “payment hubs” (i.e., Bob in the previous example) correlates with both the convenience and the usability of the Lightning Network for real-world applications.

Schnorr Signature upgrade proposal

Elliptic Curve Digital Signature Algorithm (“ECDSA”) signatures are used to sign transactions on the Bitcoin blockchain.
https://preview.redd.it/hjeqe4l7g3151.png?width=1601&format=png&auto=webp&s=8014fb08fe62ac4d91645499bc0c7e1c04c5d7c4
However, many developers now advocate for replacing ECDSA with Schnorr Signature. Once Schnorr Signatures are implemented, multiple parties can collaborate in producing a signature that is valid for the sum of their public keys.
This would primarily be beneficial for network scalability. When multiple addresses were to conduct transactions to a single address, each transaction would require their own signature. With Schnorr Signature, all these signatures would be combined into one. As a result, the network would be able to store more transactions in a single block.
https://preview.redd.it/axg3wayag3151.png?width=1601&format=png&auto=webp&s=93d958fa6b0e623caa82ca71fe457b4daa88c71e
The reduced size in signatures implies a reduced cost on transaction fees. The group of senders can split the transaction fees for that one group signature, instead of paying for one personal signature individually.
Schnorr Signature also improves network privacy and token fungibility. A third-party observer will not be able to detect if a user is sending a multi-signature transaction, since the signature will be in the same format as a single-signature transaction.

4. Economics and supply distribution

The Bitcoin protocol utilizes the Nakamoto consensus, and nodes validate blocks via Proof-of-Work mining. The bitcoin token was not pre-mined, and has a maximum supply of 21 million. The initial reward for a block was 50 BTC per block. Block mining rewards halve every 210,000 blocks. Since the average time for block production on the blockchain is 10 minutes, it implies that the block reward halving events will approximately take place every 4 years.
As of May 12th 2020, the block mining rewards are 6.25 BTC per block. Transaction fees also represent a minor revenue stream for miners.
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Merkle Trees Explained IOTA tutorial 18: Merkle Tree - YouTube Bitcoin 101 - Merkle Roots and Merkle Trees - Bitcoin ... Programmer explains Merkle Tree  Blockchain technology ... What is the merkle tree in Bitcoin? - YouTube

Merkle Tree обычно имеют коэффициент двух ветвей, что означает, что у каждого узла может быть два дочерних узла. Опять же, обычно Merkle Tree реализуются как двоичные деревья (вкл. / Выкл. Или 1/0), но опять же они могут быть созданы ... A Merkle tree is a hash-based data structure that is a generalization of the hash list. It is a tree structure in which each leaf node is a hash of a block of data, and each non-leaf node is a hash of its children. Typically, Merkle trees have a branching factor of 2, meaning that each node has up to 2 children. Merkle trees are used in distributed systems for efficient data verification. The Merkle Tree is a cryptographic invention that is essential for the health and efficient functioning of cryptocurrencies like Bitcoin. It arranges the data for transactions on the blockchain into well organized, verifiable units. It is one of the best and most effective means that the cryptocurrency community has for making sure that digital currencies continue to be legitimate and do not ... A Merkle tree, in the most general sense, is a way of hashing loads of chunks of data together which relies on splitting the chunks into buckets, where each bucket contains only a few chunks, then taking the hash of each bucket and repeating the same process, continuing to do so until the total number of hashes remaining becomes only one: the root hash. The most common and simple form of ... This page was last edited on 10 March 2015, at 23:51. Content is available under Creative Commons Attribution 3.0 unless otherwise noted.; Privacy policy; About ...

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Merkle Trees Explained

Using a concept called a Merkle tree - in this video I break it down in depth with a simple example and show how a SPV node (Simple Payment Verification) node that does not keep a full copy of the ... Explanation of cryptographic hash: https://youtu.be/IVqD-_QskW0?t=1m13s In this video I try to explain Merkle Tree. Bitcoin 101 - Merkle Roots and Merkle Trees - Bitcoin Coding and Software - The Block Header - Duration: 24:18. CRI 42,669 views Most people on earth have never even heard of Merkle roots. But bitcoin programmers deal with them every day. This is old school technology in terms of softw... If you like this video and want to support me, go this page for my donation crypto addresses: https://www.youtube.com/c/mobilefish/about This is part 18 of t...

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