Bitcoin: A Peer-to-Peer Electronic Cash System

Citation
Satoshi Nakamoto, Bitcoin: A Peer-to-Peer Electronic Cash System (full-text).

Overview
This paper proposes a solution to the double-spending problem using a peer-to-peer, distributed timestamp server to generate computational proof of the chronological order of transactions. The system is secure as long as honest nodes collectively control more CPU power than any cooperating group of attacker nodes.