<p>This book constitutes the refereed proceedings of the 18th International Conference on the Theory and Application of Cryptology and Information Security, Asiacrypt 2012, held in Beijing, China, in December 2012. </p><p>The 43 full papers presented were carefully reviewed and selected from 241 submissions. They are organized in topical sections named: public-key cryptography, foundation, symmetric cipher, security proof, lattice-based cryptography and number theory, hash function, cryptographic protocol, and implementation issues.</p>