Via Activism.net, in 1993, UC Berkeley mathematician Eric Hughes penned this manifesto for the so-called cypherpunk movement which he had helped invent:
Privacy is necessary for an open society in the electronic age. Privacy is not secrecy. A private matter is something one doesn’t want the whole world to know, but a secret matter is something one doesn’t want anybody to know. Privacy is the power to selectively reveal oneself to the world.
If two parties have some sort of dealings, then each has a memory of their interaction. Each party can speak about their own memory of this; how could anyone prevent it?
Since we desire privacy, we must ensure that each party to a transaction have knowledge only of that which is directly necessary for that transaction. When I purchase a magazine at a store and hand cash to the clerk, there is no need to know who I am.