This book constitutes the refereed proceedings of the 9th International Conference on Cryptology and Network Security, CANS 2010, held in Kuala Lumpur, Malaysia, in December 2010. The 21 revised full papers, presented together with abstracts of 2 invited talks, were carefully reviewed and selected from 64 submissions. The papers are organized in topical sections on block ciphers, wireless network security, hash functions, public key cryptography, secure mechanisms, cryptographic protocols, and anonymous credentials.