Bitcoin may have become the currency of choice for the anonymity-loving Internet underground. But it’s never been anonymous enough for Zooko Wilcox. As he’ll remind anyone who’ll listen, the blockchain, bitcoin’s very public ledger of all transactions in its crypto-economy, means that unless bitcoin’s users funnel it through intermediaries or special software, their transactions can easily be traced.
Today Wilcox and his startup Zcash are launching the first public alpha release of the cryptography world’s best shot yet at perfectly untraceable digital money. Using a mathematical sleight-of-hand known as a “zero-knowledge proof,” Zcash (until recently known as Zerocoin or Zerocash) offers the same anti-forgery assurances as bitcoin: No one can counterfeit Zcash, or spend the same Zcash “coin” twice. But thanks to its zero-knowledge feature, any spender or receiver can also choose to keep their Zcash payment entirely secret.
The company holds the potential to empower a new form of near-perfect financial privacy—or, put in the terms of less friendly financial regulators, to enable a new form of airtight money laundering. “Consumers want to buy and sell things over the Internet and need privacy from snoops who might use the knowledge of their transactions against