Zcash is a cryptocurrency aimed at using cryptography to provide enhanced privacy for its users compared to other cryptocurrencies such as Bitcoin. Zcash is based on Bitcoin's codebase. It shares many similarities such as a fixed total supply of 21 million units. Transactions can be "transparent" and similar to bitcoin transactions in which case they are controlled by a t-addr, or can be a type of zero-knowledge proof called zk-SNARKs; the transactions are then said to be "shielded" and are controlled by a z-addr. 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. 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. Zcash affords private transactors the option of "selective disclosure", allowing a user to prove payment for auditing purposes. One such reason is to allow private transactors the choice to comply with anti-money laundering or tax regulations. "Transactions are auditable but disclosure is under the participant's control." The company has hosted virtual meetings with law enforcement agencies around the U.S. to explain these fundamentals and has gone on the record of saying that "they did not develop the currency to facilitate illegal activity". On March 1, 2018, an employee named Ariel Gabizon discovered a critical bug which could have allowed an attacker to create an infinite amount of counterfeit ZCash. Gabizon shared this discovery with only three other employees, including Zooko Wilcox, the company's CEO. On October 28, 2018, the fix for this issue was covertly included in the Sapling network upgrade to the Zcash network. On May 19, 2020, a paper titled "Alt-Coin Traceability" investigated the privacy of both Zcash and 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" still continue today that 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. Chainalysis explains that it is able to accomplish this since most ZCash users do not use privacy-enhancing features. Chainalysis also cites a research paper by the RAND corporation which revealed that less than 0.2% of the cryptocurrency addresses on the dark web were ZCash addresses. On June 30, 2020, blockchain analysis company Elliptic added support for ZCash to their crypto transaction monitoring and wallet screening compliance solutions. According to the developer of ZCash, The Electric Coin Company, Zcash privacy remains strongest of any cryptocurrency, even with Chainalysis, Elliptic support. In Fall 2020, the ownership of Electric Coin Company is in the process of transitioning to a US non-profit called the Bootstrap Project.