To begin:

Dash

Monero

ZCash

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767605)

https://zcoin.io/zcoins-privacy-technology-compares-competition/

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767716)

Dash was a first generation privacy coin. It was developed as a reaction to the easy tractability of Bitcoins, and to Adversaries seeking to link different payments to the same people. Dash attempted to restore privacy through the use of CoinJoin. CoinJoin is when multiple inputs of coins are mixed together and then sent back out to multiple output addresses. This makes it difficult for third parties to tell who an output of coins came from. Many parties in a mix would send their outputs back to a fresh wallet of themselves to improve their own anonymity while also helping other parties make anonymous transactions.

Weaknesses of CoinJoin include that either a trusted third party is needed to perform the mixing, or a robust decentralized protocol. These are needed lest all of the participants learn the input-output connection. Additionally, if any of the parties to a mix later reveal the identity of their inputs/outputs, it will reduce the anonymity of the other parties. Also, bad actors can refuse to sign the transaction at the end of a mix, thus voiding the mix. Similarly, bad actors may attempt to double-spend an input to a mix before the mix has been completed. The trusted protocol/third party can keep the last element at bay, but cannot do much about parties to a mix revealing themselves.

In Dash's implementation of CoinJoin, Dash uses Masternodes to play the third party mixing role. Becoming a masternode involves staking 1,000 Dashcoin, however badactors do not lose their Dashcoins even if they misbehave. The deposit is meant to make it expensive for Adversaries to corrupt a majority of Masternodes. Each mix involves 3 parties, and multiple rounds of mixing can occur. All parties to a mix send in the same input amounts. The more rounds, the greater the anonymity.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767631)

Monero can be thought of as a one-man CoinJoin. It is a CryptoNote type privacy coin.

In Monero, one party mixes one's own Monerocoins by combining their own coins with fake inputs. The fake inputs come from other users' public coin addresses in the Monero network. By using fake inputs, the Monero users do not need to worry about trusting third party mixers, or fellow mixees.

The Monero mix uses Ring CT. That involves Traceable Ring Signatures. These are the public addresses of one's self and of other users. These are combined to produce a signature that third parties can use to verify that the output of the ring came from one of the public addresses, but the third party cannot tell which one it came from. The Traceable element of the Ring Signatures is to prevent doublespending -- third parties can verify that an input is not spent multiple times. That protects the network from double-spending attacks.

The Ring CT technology is powered by Additively Homomorphic Commitments, which is some sort of crypto math voodoo to permit miners to verify that inputs = outputs without knowing what the values of the inputs and outputs are.

Anonymity can be improved by doing a mix multiple times.

Monero transactions from before September 2017 have not been able to maintain their anonymity due to major flaws in the selection of mixing inputs. Additionally, Ring CT is now mandatory in Monero transactions to improve the anonymity set of all users. However, one weakness also in Dash remains--the users whose inputs get included in your mix can later degrade your anonymity by spending their inputs or by otherwise revealing themselves as not being the real party to your transaction.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767669)

Most of Monero's related CryptoNote coins fell by the wayside.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767755)

ZCash (aka Zerocoin aka Zerocash) uses zk-SNARKS.

ZCash is not a CoinJoin type coin.

ZCash was in the design phase around the same time as Dash and Monero came out in 2014, however it did not launch until 2016. Unlike the other two, it is based in an Ethereum token.

ZCash uses Zero Knowledge Proofs: Succinct, noninteractive arguments of knowledge to prove variables in a transaction are valid (ie that the sender had the private keys needed to send the amount of funds contemplated by his transaction) without revealing what the variables are.

Downsides of zk-SNARKS include that they are so new that they are not fully tested by cryptographers, and therefore may contain hidden weaknesses, and that they require 30-60 sections and over 3 GB memory to compute a transaction. The latter makes scalability difficult. Additionally, the community has concerns about whether the highly anonymous traits of ZCash risk its creators having been able to create limitless amounts of money at will, unless they can be trusted to have destroyed the copies of the variables they used to launch ZCash.

If the founders can be trusted, and if scalability is resolved, ZCash would be the most dominant of the early privacy coins.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767703)

https://en.wikipedia.org/wiki/Zerocoin#Zerocash_protocol

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35767718)

A spinoff of Monero designed to use masternodes to help scale, and to be a blockchain version of tor communications. Will launch as PoW and later become Proof of Space. Focus will be on “*SNApps*””SNApps are applications built on top of the layer of incentivised service nodes. They are fully decentralised, uncensorable and completely resilient to attack.”

Recently did a haphasard crowdsale. Met its $9 million goal. https://loki.network/ Hasn't yet launched, but is scheduled to launch this month.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35897652)

Basically Monero version 0.9. Created in 2012 as a CryptoNote style mixins privacy coin. Code seems to be less updated than later comer Monero. Bytecoin has been critized for being mostly premined early in its existence.

Current market cap is $890 million: #30 on coinmarketcap.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35897395)

ZCL

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35897954)

Top 8 Privacy Coins

April 16, 2018 By Steven White 27

It’s a common misconception that Bitcoin and other cryptocurrencies are fully anonymous and untraceable. In fact, many blockchains only disguise users’ identities while leaving behind a public record of all transactions that have occurred on the blockchain. The data in the ledger often includes how many tokens a user has received or sent in historical transactions, as well as the balance of any cryptocurrency that they have within their wallet.

There is a concern that even with their identities disguised, users can still be identified based on their activity within a blockchain. This is why some people turn to privacy coins – cryptocurrencies that provide users with a higher level of anonymity.

Although controversial (some authorities see privacy-oriented coins as an illicit tool that can be used by criminals to engage in illegal activities, such as money laundering), privacy coins are the safest way for users to make blockchain transactions without their financial details being exposed to the public. These platforms typically have several privacy-centric functions, like stealth addresses or private transactions, which can be used to hide user information on blockchains.

If you’re interested in learning more about privacy coins, here are our top 8 favorites that are currently available on the market.

Monero

Monero was launched in 2014, and since then it has grown to become one of the most stable and secure privacy coins released to date. Their cryptocurrency platform is the product of a Bitcoin fork but, unlike Bitcoin, Monero was created with several anonymity features. Monero effectively allows its users to have a firm command over the privacy of their data by keeping transaction information completely anonymous within the blockchain.

Monero has a few unique features that helped it grow to become the top contender in the privacy coin market.

Ring Signatures

A ring signature is a digital signature that is created by bringing a group of signers together. Monero uses this digital signature to bring multiple signers (usually 5) into each transaction. Only the sender is able to generate and send the spend key, and only the actual recipient will be able to detect the key and spend the funds linked to it. With a ring signature in place, it is impossible to link any transaction back to any one user, offering a high grade of privacy.

Ring Confidential Transactions (RingCT)

This feature hides the amount of each transaction on Monero’s network. RingCT works by creating cryptographic proof that can show that the input and output amounts are equal, without revealing any of the actual numbers.

Stealth Addresses

Monero also uses a network of stealth addresses to allow users to disconnect themselves from the blockchain. A stealth address is a one-time use address that is created for every transaction. Monero users also have a public address that is published on the blockchain, but most (if not all) of their transactions will be passed through unique stealth addresses.

With these inherently straightforward and easy to understand features, Monero has managed to remain relevant in the crypto space while offering users a completely untraceable cryptocurrency platform.

To learn more about Monero, check out “Monero 2018 Roadmap: The Future of Private Digital Currency Looks Bright” and “Should You Invest in Monero? (Opinion)“.

Zcash

Zcash is another Bitcoin-forked privacy coin, but it only has a handful of privacy features. The primary privacy feature that Zcash uses is zero-knowledge Succinct Non-Interactive Argument of Knowledge proofs (zk-SNARKs).

That name may be a mouthful to pronounce, but the basic functionality that this privacy method offers is simple to articulate. zk-SNARKS encrypt all transactional data that is stored on the network. This method verifies that the data being exchanged is accurate, but it does so without revealing all of the transaction details.

But it is important to note that using these privacy features is optional, as users can opt for transparent (public) or private addresses. Some critics believe that users choosing not to activate the privacy features may compromise the overall security of the entire network.

Dash

Dash is a bit different from the previously mentioned coins. Founded after a Bitcoin fork in 2014, it is an open-source peer-to-peer cryptocurrency that offers many of the same features as Bitcoin. But in addition to Bitcoin’s core features, Dash also includes the option for instant and private transactions.

To ensure the integrity of their system, the developers of Dash chose to implement a Proof-of-Stake protocol as well. This part of the system is designed to provide additional support to the miners that validate transactions on the first tier of the service.

Masternodes are introduced to the network for the purpose of validating transactions on the second tier of the service, which facilitates private and instant transactions as well as governance features. In order to run a masternode, a user must have at least 1,000 tokens in their wallet.

The instant-send function sends transactions along the 2nd tier of the Dash blockchain, allowing them to be confirmed quickly.

Private transactions are sent using the CoinJoin method. This method consists of attaching transactions together to make “joint payments.” But unlike a traditional joint payment, the value that was exchanged by each party and the place that the payment ended up are completely undiscoverable by third parties.

You can learn more about Dash here. Get caught up on the latest from Dash and read “Will Dash Hit its Stride in 2018 Despite Development Delays?“.

PIVX

PIVX is another new privacy coin that works similar to Dash, but operates on Proof-of-Stake rather than Proof-of-Work. PIVX users are allowed to run master nodes which help keep the network running smoothly. Commanding one of these nodes requires a stake of at least 10,000 tokens (in comparison, Dash only requires 1,000 DASH). With this much higher threshold, PIVX has more of its available token supply tied up in various master nodes.

PIVX has fast transaction verification, and supports both private and instant transactions. Transactions can be made completely anonymous, preventing discovery of a person’s real-world identity by analyzing the blockchain.

At the time of writing, the block time is about 60 seconds. Transaction fees are also quite small. These qualities make PIVX a worthy mention in the privacy coin conversation.

Visit the PIVX website to learn more about this project.

NavCoin

NavCoin is a decentralized cryptocurrency that was forked from Bitcoin. It aims to solve 2 problems that are typically found in blockchain platforms:

Data is made public on the blockchain, leaving it vulnerable to malicious attacks by illicit users.

Most blockchains use “roll backs” as the solution to data vulnerability. They reset the blockchain to a backed-up point after a data breach, meaning transactions made leading up to the roll back are erased.

The NavTech system is a combination of the traditional Bitcoin blockchain and a NAV subchain. Using two chains allows users to send transactions with complete anonymity.

Over the course of 2017, NAV managed to achieve significant growth and now manages a community of more than 50,000 users. Through 2018, they are aiming to implement a platform for building blockchain applications within the network. In addition to that goal, they also hope to add support for instant exchanges across different currencies.

Find out more about NavCoin on their website.

CloakCoin

cloakcoin

Cloak is a veteran privacy coin that is growing slowly, although it has been active in the privacy niche for approximately 4 years. The blockchain is operated using a Proof-of-Stake consensus protocol. It has relatively short blocktimes and quickly processes transactions.

The platform also offers 2 different methods of making your transactions untraceable.First is their onion-routing privacy protocol. Onion routing involves encrypting messages with many layers (similar to an onion).

It also offers the Enigma process to provide additional privacy cloaking on transactions. Enigma cloaking is applied when a user requests a cloaked enigma transaction. These transactions are carried across dedicated Enigma nodes, which are designed to cloak transaction data by shuffling it with other random data. Only these Enigma nodes are able to identify if the input and output data is accurate.

To learn more about CloakCoin, check out their whitepaper.

Enigma

The Enigma project is entirely separate from the Enigma cloaking process used in CloakCoin transactions. Enigma is not a cryptocurrency nor a blockchain; instead, it is a privacy protocol that can be deployed on blockchains and decentralized applications. Therefore its token, ENG, is a distinct addition to the list of top privacy coins.

The Enigma network provides privacy by making nodes unable to see the data that they compute. Although they are unable to clearly see exactly what they are working on, these nodes are still capable of verifying that their computations have been run correctly. With the data masked like this, Enigma hopes to open the door for what they call a new type of smart contracts – “secret contracts” – wherein the underlying data processed in a smart contract remains encrypted at all times.

Enigma’s token must be purchased in order to run a node on their network. After buying the Enigma token, you can receive rewards for processing data. But in order to process data, each node must make a security deposit. If the data is tampered during the verification process, the deposit will be split between any nodes that processed the data without error.

In effect, owning ENG allows people to get started using the network. ENG also serves as a reward for participation in the network.

To learn more about Enigma, click here.

DeepOnion

DeepOnion is a new privacy coin project that is generating some interest in the community. Like a few of the other coins in this list, DeepOnion uses TOR to send untraceable transactions. It also uses a mix of Proof-of-Stake and Proof-of-Work protocols to offer fast confirmation times.

DeepOnion also employs stealth addresses to keep transactions private. As mentioned before, a stealth address allows the sender to use a one-time user address for their transactions. The recipient only needs a single address, but before they receive the value that is sent, that block is sent to unique addresses on the chain where they cannot be connected to the sender or recipient’s personal address. This ensures that only the sender and receiver can consistently know where payments originated and where they were sent.

The DeepOnion team is currently working on DeepSend and DeepVault. DeepSend will use a multi-signature method to prevent payments from being traced. DeepVault is an information storage service that allows users to store data in the blockchain forever. To be more precise, DeepVault allows users to store hashes of files within the blockchain. In order to verify the integrity of a file, a user only needs to compare their current version of the file with the backup. This can be beneficial for the purpose of verifying the integrity of important documents.

As the community develops, DeepOnion will also launch their VoteCentral function. It will allow users of the platform to vote on new developments and present their ideas for future projects. This project is small now, but in some regards it does show promise.

Visit the DeepOnion website to learn more.

Conclusion

Privacy coins are a niche group of cryptocurrencies. Some people may have no concerns about whether their transaction history is discoverable by third parties. But others might adamantly refuse to participate in any cryptocurrency platform that cannot guarantee them complete privacy.

If you are interested in investing in blockchain but have concerns about personal privacy, consider getting started with some of the privacy coins mentioned here.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#35910311)

Looks like we can summarize these as

PIVX: Dash, except PoS

Nav: A privacy subchain for Bitcoin Core

Cloakcoin: Dash minus masternodes, and with PoS

Enigma: A token for a data privacy node integration for other blockchains

DeepOnion: Dash minus masternodes and run on Tor, with plans to add monero multisigs, and Storj storage

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#36002774)

Don't think this one has launched yet. Hotness. Main weakness is a lack of smart contracts. But for a bitcoin type privacy coin this could set the gold standard. Trims all the fat from the blockchain to have everything be quickly auditable. Otherwise similar to Monero only faster and not run by a fluffy pony.

Mimblewimble was created by Lord Voldermort (aka 45)

Grin is the implementation attempt of 45's plan, except that it leaves off some of the sinking signature blockchain trimming stuff.

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#36532255)

Masternode with strange integrations with ZRX exchanges... super small cap, has raped me by falling from $12 to $2.50 since Jan (high was $60!)

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#36536352)

They're finding their own exchange called txbit launching in Q4

Bulwark announced they're launching an exchange too

(http://www.autoadmit.com/thread.php?thread_id=3939805&forum_id=7#36536426)