From Wikipedia:

"A cypherpunk is any activist advocating widespread use of strong cryptography and privacy-enhancing technologies as a route to social and political change. Originally communicating through the Cypherpunks electronic mailing list, informal groups aimed to achieve privacy and security through proactive use of cryptography. Cypherpunks have been engaged in an active movement since the late 1980s."

Wikipedia page: https://en.wikipedia.org/wiki/Cypherpunk

Cypherpunk Manifesto: https://www.activism.net/cypherpunk/manifesto.html