Bitcoin privacy

Zerocash, the protocol that succeeded Zerocoin, is being developed into a full-fledged digital currency, Zcash. Zerocoin is a project to fix a major weakness in Bitcoin: the lack of privacy guarantees we take for granted in using credit cards and cash. Our goal is to build a cryptocurrency where your neighbors, friends and bitcoin privacy can’t see what you bought or for how much.

Bitcoin protocol that allowed users to mix their own coin. A collaboration between the the original Zerocoin project members and cryptographers at MIT, The Technion, and Tel Aviv University, has produced a far more efficient protocol that allows for direct private payments to otherusers of hidden value. The problem: Bitcoin is not private The Bitcoin payment network offers a highly decentralized mechanism for creating and transferring electronic cash around the world. Bitcoin transactions are conducted using public keys as identifiers, and these public keys are not linked to individual names.

Unfortunately, a growing body of research indicates that these protections are insufficient. Laundries suffer from a number of potential drawbacks, however, as they must be trusted to return coins. Moreover a compromised or malicious laundry offers no anonymity. Zerocoin and the Zerocash protocol operates in the Bitcoin network and is implemented as a series of extensions to the existing Bitcoin protocol. Moreover, since no single trusted party operates the Zerocoin system, attacks on Zerocoin must take on a substantial fraction of the Bitcoin network. The Zerocash protocol uses provably secure cryptographic techniques to ensure that Bitcoins cannot be traced.

These techniques allow users to conduct transactions on the Bitcoin network while receiving strong mathematical guarantees that the transactions cannot be traced. These guarantees remain in place even if a portion of the Bitcoin network is compromised by an attacker. Other anonymous cash systems rely on distributing the work of anonymizing users amongst a set of parties. Because Zerocoin is built on top of Bitcoin, it is widely distributed among all the Bitcoin peers, ensuring that the system can remain available even when many nodes are compromised.