This book constitutes the refereed proceedings of the 4th Theory of Cryptography Conference, TCC 2007, held in Amsterdam, The Netherlands in February 2007. The 31 revised full papers cover encryption, universally composable security, arguments and zero knowledge, notions of security, obfuscation, secret sharing and multiparty computation, signatures and watermarking, private approximation and black-box reductions, and key establishment.

This book constitutes the refereed proceedings of the 4th Theory of Cryptography Conference, TCC 2007, held in Amsterdam, The Netherlands in February 2007. The 31 revised full papers cover encryption, universally composable security, arguments and zero knowledge, notions of security, obfuscation, secret sharing and multiparty computation, signatures and watermarking, private approximation and black-box reductions, and key establishment.