This book constitutes the refereed proceedings of the 29th Annual International Cryptology Conference CRYPTO 2009 held in Santa Barbara CA USA in August 2009. The 38 revised full papers presented were carefully reviewed and selected from 213 submissions. Addressing all current foundational theoretical and research aspects of cryptology cryptography and cryptanalysis as well as advanced applications the papers are organized in topical sections on key leakage hash-function cryptanalysis privacy and anonymity interactive proofs and zero-knowledge block-cipher cryptanalysis modes of operation elliptic curves cryptographic hardness merkle puzzles cryptography in the physical world attacks on signature schemes secret sharing and secure computation cryptography and game-theory cryptography and lattices identity-based encryption and cryptographers toolbox.