This book constitutes the refereed proceedings of the 30th Annual International Cryptology Conference, CRYPTO 2010, held in Santa Barbara, CA, USA in August 2010, co-located with CHES 2010, the workshop on Cryptographic Hardware and Embedded Systems. The 39 revised full papers presented were carefully reviewed and selected from 203 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 leakage, lattice, homomorphic encryption, theory and applications, key exchange, OAEP/RSA, CCA, attacks, composition, computation delegation and obfuscation, multiparty computation, pseudorandomness, and quantum.