"Advances in Cryptology - EUROCRYPT 2009" is a comprehensive collection of scholarly contributions documenting the results of the 28th International Conference on the Theory and Applications of Cryptographic Techniques. This conference took place in April 2009 in Cologne, Germany, and attracted numerous submissions from around the world. Out of 148 submitted papers, 33 revised full texts and one invited lecture were selected, addressing the latest developments in cryptology, cryptography, and cryptanalysis. The contributions are organized into thematic sections that cover various aspects of security, proofs, models, hash cryptanalysis, group and broadcast encryption, cryptosystems, cryptanalysis, side channels, curves, and randomness. This book is a valuable resource for researchers and practitioners dealing with the theoretical and practical challenges of modern cryptography.