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Zcash

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This article is about the cryptocurrency Zcash; not to be confused with Zerocoin or zcache.

Zcash
Denominations
CodeZEC
Development
White paperZcash Protocol Specification
Initial release28 October 2016; 9 years ago (2016-10-28)
Latest release6.11.0 / 10 January 2026; 3 months ago (2026-01-10)[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]
Supply limit21,000,000[2]
Website
Websitez.cash

Zcash is a privacy-focused cryptocurrency which features an encrypted ledger using zero-knowledge proofs.[4]

Launched in October 2016, Zcash was developed by cryptographers at Johns Hopkins University and MIT and derived its code from bitcoin.[5][6][7][8] Zcash was one of the first large-scale implementations of zero-knowledge proofs outside of academia.[9][10][11]

Design

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Zcash is modeled on bitcoin, sharing its 21 million coin supply cap and proof-of-work consensus mechanism.[5][12][13] Zcash uses the Equihash memory-hard proof-of-work algorithm, which was chosen to resist centralization of mining by specialized hardware.[13] The protocol bridges the transparent payment scheme used by bitcoin with a shielded payment scheme secured by zk-SNARKs (zero-knowledge succinct non-interactive arguments of knowledge).[13][5][14][11] Shielded transactions can be verified as valid without revealing the sender, recipient, or amount transferred.[6][12][13]

Zcash supports two types of addresses: transparent addresses, which function similarly to bitcoin addresses with publicly visible transactions, and shielded addresses, which use zero-knowledge proofs to encrypt transaction data.[5][15][12][13] Users can transact between the two types, allowing funds to move between the transparent and shielded pools.[5][13]

Value held in a shielded address is represented by a note, which records an amount and a recipient address.[13] When a note is created, only a cryptographic commitment to the note is published on the blockchain, and the commitment is added to an append-only Merkle tree of all note commitments.[13] When a note is spent, the sender publishes a unique value called a nullifier and a zero-knowledge proof that the nullifier corresponds to some previously committed note, without revealing which one.[13] Nullifiers are recorded in a set shared across the network, and a transaction is rejected if it would add a nullifier already present in the set, which prevents double-spending.[13] Because a spent note cannot be linked to the transaction that created it, the set of notes from which any given spent note could have originated includes all previously created notes that have not been spent.[13] Unlike mixing-based privacy systems, which obscure transactions among a limited set of participants, this approach makes each spent note indistinguishable from all other unspent notes on the network.[13]

The shielded transaction system has undergone three generations, known as Sprout, Sapling, and Orchard, each modifying the cryptographic constructions used for shielded transfers.[13]

This optional privacy model is intended to preserve fungibility, ensuring that all units of the currency are treated equally regardless of their transaction history.[12][6] Users also have the option to share private viewing keys, allowing designated third parties to see their transaction details for auditing purposes.[12][16] From the Sapling upgrade onward, each spending key has an associated full viewing key that allows recognizing both incoming and outgoing transactions without granting spending authority.[13]

History

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Development work on Zcash began in 2013 by Johns Hopkins University professor Matthew Green and his graduate students Ian Miers and Christina Garman, who developed the Zerocoin protocol. They subsequently joined forces with a team of cryptographers including Alessandro Chiesa and Madars Virza from MIT, and Eli Ben-Sasson from the Technion and Eran Tromer from Tel Aviv University, who had developed a more efficient variant called zk-SNARKs.[5][17][9][16] The development was completed by the for-profit Zcash Company, led by Zooko Wilcox, a Colorado based computer security specialist.[5] The Zcash Company raised over $3 million from investors including Naval Ravikant.[5][17]

Zcash was first mined in late October 2016.[12] To generate revenue, 10% of all coins mined for the first four years were automatically distributed to the Zcash Company and the Zcash Foundation.[5]

The instantiation of the Zcash network required the creation of a master private key. To ensure privacy, this private key must later be destroyed, otherwise counterfeit Zcash coins could be generated. To maximize the chance that no one person could obtain the private key, software was written which allowed individuals from six different locations to collaboratively generate the private key, use it to instantiate Zcash, and then destroy the computers used in the process afterwards.[18][17][10] In 2019, Electric Coin Company researcher Sean Bowe discovered Halo, a technique for generating zero-knowledge proofs without requiring a trusted setup ceremony.[9][19][20] This eliminated the need for the elaborate multi-party ceremonies used at launch.

In 2022, Edward Snowden revealed that he had participated in the creation of Zcash under the pseudonym "John Dobbertin."[21][22][23] Other participants in the ceremony included Peter Todd, a Bitcoin Core developer.[21]

On February 21, 2019, the "Zcash Company" announced a rebranding as the Electric Coin Company (ECC).[24] In 2020, the Electric Coin Company transitioned to nonprofit ownership, becoming a wholly owned subsidiary of the Bootstrap Project, a 501(c)(3) organization.[25]

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 a 51% attack, where they could potentially manipulate transactions and harm the network. In response, Coinbase placed Zcash markets into "limit-only" mode in an effort to prevent significant price swings.[26]

In April 2026, Foundry, one of the largest bitcoin mining pool operators, launched a dedicated Zcash mining pool.[27] As of April 2026, Foundry stated that the pool had attracted multiple institutional mining customers and accounted for close to a third of new Zcash issuance.[27] Foundry CEO Mike Colyer attributed the launch to institutional interest in privacy-preserving cryptocurrencies, citing Zcash's support for selective disclosure.[27]

Adoption and recognition

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In 2017, JPMorgan Chase integrated Zcash's zero-knowledge proof technology into its enterprise blockchain platform Quorum to enable confidential transactions for business clients.[17][14][28] Fortune reported that Zcash's fundamental technology would be added to the Ethereum network.[17]

In late 2017, Grayscale Investments, a subsidiary of Digital Currency Group, launched a Zcash Investment Trust, making it one of only three cryptocurrencies for which the firm offered a dedicated fund alongside bitcoin and Ethereum Classic.[29][30]

In 2018, MIT Technology Review named Zcash co-founder Alessandro Chiesa, an assistant professor at the University of California, Berkeley, to its Innovators Under 35 list for his work on the zero-knowledge proof technology underlying the cryptocurrency.[31]

In May 2018, the New York State Department of Financial Services approved Zcash for trading on Gemini, the first such approval for a privacy-focused cryptocurrency in the United States.[32][33][34][35]

In May 2018, Bloomberg and Galaxy Digital launched the Bloomberg Galaxy Crypto Index, which included Zcash as one of approximately ten tracked cryptocurrencies.[36]

The Freedom of the Press Foundation, the Human Rights Foundation, and the Electronic Frontier Foundation have accepted Zcash donations.[37][38]

Privacy

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In 2016, Tom Robinson, co-founder of blockchain tracing firm Elliptic, told CNBC that Zcash appeared to have achieved a high level of anonymity.[39] A 2018 study found that while it is possible to use Zcash privately, the anonymity set of the shielded pool could be reduced through heuristics-based analysis of usage patterns.[40] The analysis predates subsequent protocol upgrades to the shielded transaction system.[9]

In his 2022 book on cryptocurrency tracing, journalist Andy Greenberg described Zcash's shielded transactions as "provably inaccessible" to surveillance and said he had not seen evidence that its anonymity could be compromised.[41][42]

Law enforcement

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In 2017, the European Union's law enforcement agency Europol flagged Zcash, along with bitcoin and Monero, for potential use in internet-based crime.[43] The same report noted that Zcash was not known to have a significant criminal following.[43] In 2018, several Japanese exchanges delisted Zcash and other privacy-focused cryptocurrencies citing regulatory pressure following a major exchange hack; the delisted coins had not been involved in the hack.[44][45]

A 2020 research report by the RAND Corporation examined eight major dark web marketplaces and found that 59% of cryptocurrency mentions were bitcoin and 27% were Monero, compared with less than 1% for Zcash, concluding that there was "little evidence" that privacy coins were preferred by criminals despite their anonymity features.[15][44] A 2023 analysis of cryptocurrency and crime similarly found that Zcash held less appeal to criminals than other privacy coins, noting that it "featured very rarely on the dark web" compared to Monero.[46]

See also

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References

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  1. ^ "Releases - zcash/zcash". Retrieved 21 March 2026 – via GitHub.
  2. ^ a b c "Frequently Asked Questions - Zcash". Zcash. Archived from the original on 24 June 2019. Retrieved 10 July 2019.
  3. ^ "Canopy". Archived from the original on 17 April 2023. Retrieved 17 April 2023.
  4. ^ Carlisle, David (26 December 2023). The Crypto Launderers: Crime and Cryptocurrencies from the Dark Web to DeFi and Beyond. John Wiley & Sons. p. 70. ISBN 978-1-394-20319-2.
  5. ^ a b c d e f g h i Popper, Nathaniel (31 October 2016). "Zcash, a Harder-to-Trace Virtual Currency, Generates Price Frenzy". The New York Times. Archived from the original on 11 January 2019. Retrieved 26 January 2017.
  6. ^ a b c Hackett, Robert (29 October 2016). "Meet the Latest Hyped Cryptocurrency". Fortune.
  7. ^ Orcutt, Mike (9 November 2017). "A Mind-Bending Cryptographic Trick Promises to Take Blockchains Mainstream". MIT Technology Review.
  8. ^ Greenberg, Andy (20 January 2016). "Zcash, an Untraceable Bitcoin Alternative, Launches in Alpha". WIRED.
  9. ^ a b c d Weiss, Ben (5 June 2023). "A brief history of zero-knowledge proofs, the buzzy mathematical technique that's taken crypto by storm". Fortune. Retrieved 22 March 2026.
  10. ^ a b Peck, Morgen E. (2 December 2016). "The Crazy Security Behind the Birth of Zcash, the Inside Story". IEEE Spectrum.
  11. ^ a b "Known unknown". The Economist. 27 October 2016.
  12. ^ a b c d e f Elaine, Ou (1 November 2016). "Bitcoin Isn't Anonymous Enough". Bloomberg.com. Bloomberg. Retrieved 17 November 2020.
  13. ^ a b c d e f g h i j k l m n "Zcash Protocol Specification" (PDF). Retrieved 31 March 2026.
  14. ^ a b Orcutt, Mike (24 November 2017). "Why America's Biggest Bank Digs Anonymous Cryptocurrency". MIT Technology Review.
  15. ^ a b 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". Archived from the original on 21 September 2020. Retrieved 5 September 2020.
  16. ^ a b Peck, Morgen E. (18 November 2016). "A Blockchain Currency That Beats Bitcoin On Privacy". IEEE Spectrum.
  17. ^ a b c d e Hackett, Robert (18 December 2017). "Can This Man Build a Better Bitcoin?". Fortune.
  18. ^ Webster, Molly; Kielty, Matt (25 February 2021). "The Ceremony". Radiolab. National Public Radio. Archived from the original on 28 June 2021. Retrieved 29 June 2021.
  19. ^ Bowe, Sean; Grigg, Jack; Hopwood, Daira (2019). "Recursive Proof Composition without a Trusted Setup". Cryptology ePrint Archive.
  20. ^ Hackett, Robert (5 February 2019). "Zcash Discloses Vulnerability That Could Have Allowed 'Infinite Counterfeit' Cryptocurrency". Fortune.
  21. ^ a b Locke, Taylor (28 April 2022). "Edward Snowden says he's the mystery man involved in the creation of leading privacy cryptocurrency Zcash". Fortune. Archived from the original on 2 November 2022. Retrieved 2 November 2022.
  22. ^ del Castillo, Michael (27 April 2022). "Edward Snowden Revealed As Key Participant In Mysterious Ceremony Creating $2 Billion Anonymous Cryptocurrency". Forbes.
  23. ^ Christensen, Meg (29 April 2022). "Edward Snowden Taught Zcash CEO Zooko Wilcox A CIA Trick To Help Keep The Creation Ceremony Secure". Forbes.
  24. ^ "Goodbye, Zcash Company. Hello, Electric Coin Company". Electric Coin Company. 21 February 2019. Archived from the original on 21 October 2020. Retrieved 9 November 2020.
  25. ^ "ECC owners approve donation to Bootstrap Project". Electric Coin Company. 27 October 2020. Archived from the original on 9 November 2020. Retrieved 9 November 2020.
  26. ^ "Crypto and the Curse of the 51%". Bloomberg.com. 26 September 2023. Archived from the original on 27 September 2023. Retrieved 24 December 2023.
  27. ^ a b c Roberts, Jeff John (13 April 2026). "Bitcoin mining giant Foundry adds new pool for privacy-focused Zcash". Fortune. Retrieved 21 April 2026.
  28. ^ Hackett, Robert (24 May 2018). "How JPMorgan Chase Learned to Love the Blockchain". Fortune.
  29. ^ Hackett, Robert (31 January 2018). "One of Bitcoin's Biggest Asset Managers Says Zcash Could Hit $60,000 in 2025". Fortune.
  30. ^ Irrera, Anna; Stecklow, Steve (24 December 2017). "Special Report - Ex-banker cheerleads his way to cryptocurrency riches". Reuters.
  31. ^ Solomon, Dan (27 June 2018). "Alessandro Chiesa". MIT Technology Review.
  32. ^ Kharif, Olga (14 May 2018). "'Privacy Coin' ZCash Lands on Winklevoss's Gemini Exchange". Bloomberg.com.
  33. ^ Shen, Lucinda (15 May 2018). "Here's Why Cryptocurrency Zcash Is Soaring While Bitcoin Languishes". Fortune.
  34. ^ "DFS Authorizes Gemini Trust Company to Provide Additional Virtual Currency Products and Services". New York State Department of Financial Services. 14 May 2018.
  35. ^ Stempel, Jonathan (14 May 2018). "New York lets Winklevoss firm offer new cryptocurrency services". Reuters.
  36. ^ Irrera, Anna (9 May 2018). "Novogratz teams up with Bloomberg on crypto index". Reuters.
  37. ^ Liao, Shannon (18 June 2018). "The Freedom of the Press Foundation now accepts bitcoin cash, ether, and other cryptocurrencies". The Verge.
  38. ^ del Castillo, Michael (6 May 2020). "Cypherpunk Zooko Wilcox Aims To Bring Anonymous Zcash To Law-Abiding Masses". Forbes.
  39. ^ Graham, Luke (31 October 2016). "New bitcoin rival promises anonymity for online purchases". CNBC.
  40. ^ 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. Archived from the original on 26 April 2020. Retrieved 17 April 2020.
  41. ^ Greenberg, Andy (2022). Tracers in the Dark: The Global Hunt for the Crime Lords of Cryptocurrency. Doubleday. ISBN 978-0-385-54809-0.
  42. ^ Starks, Tim (15 November 2022). "Andy Greenberg on how 'Tracers in the Dark' found the dark web's worst criminals". CyberScoop.
  43. ^ a b Kharif, Olga (2 January 2018). "The Criminal Underworld Is Dropping Bitcoin for Another Currency". Bloomberg.com.
  44. ^ a b del Castillo, Michael (12 May 2020). "Privacy Coins Monero, Zcash And Dash Face Uphill Battle In Japan". Forbes.
  45. ^ Evans, Jon (24 June 2018). "Zcash: life on the crypto roller coaster". TechCrunch.
  46. ^ Carlisle, David (26 December 2023). The Crypto Launderers: Crime and Cryptocurrencies from the Dark Web to DeFi and Beyond. John Wiley & Sons. pp. 70–73. ISBN 978-1-394-20319-2.
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