This book constitutes the refereed proceedings of the 8th International Conference on Cryptology and Network Security, CANS 2009, held in Kanazawa, Japan, in December 2009. The 32 revised full papers presented together with 3 invited talks were carefully reviewed and selected from 109 submissions. The papers are organized in topical sections on cryptographic prools and schemes; cryptanalysis; wireless and sensor security; network security; privacy and anonymity; functional and searchable encryption; authentication; block cipher design; and algebraic and number-theoretic schemes.