What is a cypherpunk?

The cypherpunks began as an email list, started in late 1992 by Eric Hughes, Timothy May and John Gilmore. Programmers, cryptographers and privacy activists argued there about how cryptography could protect people from surveillance. By 1997 the list had perhaps 2,000 subscribers.

Eric Hughes set out their thinking in A Cypherpunk’s Manifesto in 1993: “Privacy is necessary for an open society in the electronic age.” Rather than wait for laws to protect privacy, they would build the tools themselves: “Cypherpunks write code.”

Several of Bitcoin’s building blocks came from that world. Adam Back announced hashcash on the list in 1997; its proof of work is what Bitcoin’s miners do today. Wei Dai announced b-money there in 1998. The Bitcoin white paper cites both, and Hal Finney and Nick Szabo, who designed earlier forms of digital money, were part of the same circle.