Here are the refereed proceedings of the 5th International Conference on Security and Cryptology for Networks, SCN 2006. The book offers 24 revised full papers presented together with the abstract of an invited talk. The papers are organized in topical sections on distributed systems security, signature schemes variants, block cipher analysis, anonymity and e-commerce, public key encryption and key exchange, secret sharing, symmetric key cryptanalisis and randomness, applied authentication, and more.