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Zcash
Denominations
CodeZEC
Development
White paperZcash Protocol Specification
Initial release28 October 2016; 7 years ago (2016-10-28)
Latest release5.7.0 / 13 March 2023; 10 months ago (2023-03-13)[1]
Code repositorygithub.com/zcash/zcash
Development statusActive
Project fork ofBitcoin Core
Written inC++ and Rust (zcashd), Python (zcashd test suite), Rust (zebra), Kotlin (Android SDK), Swift (iOS SDK), Go (lightwalletd)
Operating systemLinux, Windows, macOS
Developer(s)Electric Coin Company (zcashd), Zcash Foundation (zebra)
Source modelOpen source
LicenseMIT (main zcashd code); MIT/Apache (zebra and some support libraries); BOSL (orchard)
Ledger
Hash functionEquihash
Issuance scheduleSimilar to Bitcoin, with "slow start" and different block interval
Block reward3.125 ZEC (80% to miners; 20% is portioned out to a Major Grants Fund (8%), Electric Coin Co (7%), and the Zcash Foundation (5%)), from Canopy upgrade until first halving[2][3]
Block time75 seconds (post-Blossom upgrade)[2]
Block explorerzcashblockexplorer.com
Supply limit21,000,000[2]
Website
Websitez.cash

Zcash is a privacy-focused cryptocurrency which is based on Bitcoin's codebase.[4] It shares many similarities, such as a fixed total supply of 21 million units.[5]

Transactions can be transparent, similar to bitcoin transactions, or they can be shielded transactions which use a type of zero-knowledge proof to provide anonymity in transactions. Zcash coins are either in a transparent pool or a shielded pool.

Zcash offers private transactors the option of "selective disclosure", allowing a user to prove payment for auditing purposes. One such reason is to make it easier for private transactors to comply with anti-money laundering laws and tax regulations.[6]

Use

Zcash transactions can be transparent, similar to bitcoin transactions, in which case they are controlled by a "t-addr", or they can be shielded and are controlled by a "z-addr". A shielded transaction uses a type of zero-knowledge proof, specifically a non-interactive zero-knowledge proof, called "zk-SNARK", which provides anonymity to the coin holders in the transaction. Zcash coins are either in a transparent pool or a shielded pool. As of December 2017 only around 4% of Zcash coins were in the shielded pool and at that time most cryptocurrency wallet programs did not support z-addrs and no web-based wallets supported them.[7] The shielded pool of Zcash coins were further analyzed for security and it was found that the anonymity set can be shrunk considerably by heuristics-based identifiable patterns of usage.[8]

While miners receive 80% of a block reward, 20% is given to the "Zcash development fund": 8% to Zcash Open Major Grants, 7% to Electric Coin Co., and 5% to The Zcash Foundation.[9][10]

History

Development work on Zcash began in 2013 by Johns Hopkins University professor Matthew Green and some of his graduate students.[5] The development was completed by the for-profit Zcash Company, led by Zooko Wilcox, a Colorado-based computer security specialist and cypherpunk.[5] In October 2016, The Zcash Company raised over $3 million from Silicon Valley venture capitalists to complete the development of Zcash.[5]

Zcash was first mined in late October 2016.[11] The initial demand was high, and within a week Zcash coins were trading for five thousand dollars a piece.[11] Ten percent of all coins mined for the first four years were to be allotted to the Zcash Company, its employees, the investors, and the non-profit Zcash Foundation.[5]

The setup of Zcash required the careful execution of a trusted setup procedure — something that subsequently became known as "The Ceremony" — to create the Zcash private key. In order to ensure privacy, a truly random enormous number needed to be generated to be used as the private key, while also ensuring that no person or computer retains a copy of the key, or could subsequently regenerate the key. If the private key were available, counterfeit Zcash coins could be generated. The Ceremony was a two-day process, executed simultaneously during a short window of time in six different locations globally, by persons who did not know in advance who else was going to be participating in the event. The private key was generated, and used to instantiate Zcash, and the computers used in the process were reportedly destroyed.[12][13] In 2022, Edward Snowden claimed to have participated in The Ceremony under a pseudonym.[14]

On February 21, 2019, the "Zcash Company" announced a re-branding as the Electric Coin Company (ECC).[15]

On May 19, 2020, a paper titled "Alt-Coin Traceability"[16] investigated the privacy of Zcash and another cryptocurrency Monero. This paper concluded that "more academic research is needed in Zcash overall" and that the privacy guarantees of Zcash are "questionable". The paper claimed that, since the current heuristics from a 2018 Usenix Security Symposium paper entitled "An Empirical Analysis of Anonymity in Zcash"[8] still continue today, the result is making Zcash less anonymous and more traceable.

On June 8, 2020, Chainalysis added support for Zcash to their Chainalysis Reactor and "Know Your Transaction" (KYT) technologies. This permits Chainalysis to trace and provide transaction values and at least the sender or receiver address for over 99% of Zcash activity. According to Chainalysis, it is able to accomplish this because most Zcash users do not use privacy-enhancing features.[17] Chainalysis also cites a research report by the RAND corporation which revealed that less than 0.2% of the cryptocurrency addresses on the dark web were Zcash addresses.[18][17][non-primary source needed]

On October 12, 2020, the Electronic Coin Company announced a new non-profit 501(c)3 organization called the Bootstrap Project (Bootstrap) in a company blog post titled "ECC’s owners to donate ECC".[19] A majority of the investors and owners of Zerocoin Electric Coin Company LLC (ECC) have agreed to donate the ECC company as the wholly owned property of Bootstrap.[19] ECC's blog post claims that nothing will change within the company other than the ownership[19] including the Board of Directors.[19] On October 27, 2020, ECC announced that its shareholders have officially voted in favor of donating 100 percent of the company's shares to Bootstrap.[20] On March 30, 2021, the company's transparency report said that it is "now a wholly owned entity of the 501(c)3 Bootstrap".[21][22]

In September 2023, a mining pool named ViaBTC had seized control of over half the hashing power on Zcash. This 51% dominance raised worries about an attack a 51% attack where they could potentially manipulate transactions and harm the network. To shield users from the potential fallout, Coinbase swiftly enacted a series of defensive measures, including placing Zcash markets into "limit-only" mode, effectively quelling significant price swings while the situation unfolded. [23]

See also

References

  1. ^ "Releases - zcash/zcash". Retrieved 4 April 2023 – via GitHub.
  2. ^ a b c "Frequently Asked Questions - Zcash". Zcash. Retrieved 10 July 2019.
  3. ^ "Canopy". Retrieved 17 April 2023.
  4. ^ "The Basics | Zcash". Zcash. Retrieved 10 July 2020.
  5. ^ a b c d e Popper, Nathaniel (31 October 2016). "Zcash, a Harder-to-Trace Virtual Currency, Generates Price Frenzy". The New York Times.
  6. ^ Clozel, Lalita (31 October 2016). "How Zcash Tries to Balance Privacy, Transparency in Blockchain". American Banker.
  7. ^ Quesnelle, Jeffrey (2017). "On the linkability of Zcash transactions". arXiv:1712.01210 [cs.CR].
  8. ^ a b Kappos, George; Yousaf, Haaroon; Maller, Mary; Meiklejohn, Sarah (2018). An Empirical Analysis of Anonymity in Zcash. pp. 463–477. ISBN 978-1-939133-04-5.
  9. ^ "Zcash development and governance - Zcash". Zcash. Retrieved 22 June 2021.
  10. ^ "Reaching Consensus". Electric Coin Company. Retrieved 22 June 2021.
  11. ^ a b Elaine, Ou (1 November 2016). "Bitcoin Isn't Anonymous Enough". Bloomberg.com. Bloomberg. Retrieved 17 November 2020.
  12. ^ Webster, Molly; Kielty, Matt (25 February 2021). "The Ceremony". Radiolab. National Public Radio. Retrieved 29 June 2021.
  13. ^ "Zcash: Meet Zooko Wilcox, the Man Building a Better Bitcoin | Fortune". 21 December 2017. Archived from the original on 21 December 2017. Retrieved 27 December 2022.
  14. ^ "Edward Snowden says he was the mystery man involved in the creation of leading privacy cryptocurrency Zcash". Fortune. Retrieved 2 November 2022.
  15. ^ "Goodbye, Zcash Company. Hello, Electric Coin Company". Electric Coin Company. 21 February 2019. Retrieved 9 November 2020.
  16. ^ Ye, Claire; Ojukwu, Chinedu; Hsu, Anthony; Hu, Ruiqi (2020). "Alt-Coin Traceability". Cryptology ePrint Archive.
  17. ^ a b "Introducing Investigation and Compliance Support for Dash and Zcash". blog.chainalysis.com. 8 June 2020. Retrieved 5 September 2020.
  18. ^ Silfversten, Erik; Favaro, Marina; Slapakova, Linda; Ishikawa, Sascha; Liu, James; Salas, Adrian (6 May 2020). "Exploring the use of Zcash cryptocurrency for illicit or criminal purposes".
  19. ^ a b c d "ECC's owners to donate ECC". Electric Coin Company. 12 October 2020. Retrieved 8 November 2020.
  20. ^ "ECC owners approve donation to Bootstrap Project". Electric Coin Company. 27 October 2020. Retrieved 9 November 2020.
  21. ^ "ECC Transparency Report for Q3 2020". Electric Coin Company. 30 March 2021. Archived from the original on 30 March 2021. Retrieved 2 April 2021.
  22. ^ "Electric Coin Co. Transparency Report March 2021" (PDF). 31 March 2021. Archived (PDF) from the original on 2 April 2021. Retrieved 2 April 2021.
  23. ^ "Crypto and the Curse of the 51%". Bloomberg.com. 26 September 2023. Retrieved 24 December 2023.