Crypto-anarchy is the use of crypography and encryption to anonymize communications, with the participants only revealing information that they choose to.  The effect of this is an economy that operates outside of exisiting governmental institutions.

From The Cypto-Anarchist Manifesto

"Two persons may exchange messages, conduct business, and negotiate electronic contracts without ever knowing the True Name, or legal identity, of the other. Interactions over networks will be untraceable, via extensive re- routing of encrypted packets and tamper-proof boxes which implement cryptographic protocols with nearly perfect assurance against any tampering...These developments will alter completely the nature of government regulation, the ability to tax and control economic interactions, the ability to keep information secret, and will even alter the nature of trust and reputation."