Financial Cryptography : 8th International Conference FC 2004 Key West FL USA February 9 12 2004. Revised Papers This book constitutes the thoroughly refereed post proceedings of the 8th International Conference on Financial Cryptography FC 2004 held in Key West FL USA in February 2004. The 17 revised full papers presented together with abstracts of 4 invited talks and 4 panel statements were carefully reviewed and selected for inclusion in the book. The papers are organized in topical sections on loyalty and micropayment systems user authentication e voting auctions and lotteries game theoretic and cryptographic tools and mix networks and anonymous communications