The 24th Annual International Cryptology Conference (Crypto 2004) was held in Santa Barbara, California, from August 15-19, 2004. It was sponsored by the International Association for Cryptologic Research (IACR) in cooperation with the IEEE Computer Society Technical Committee on Security and Privacy and the Computer Science Department of the University of California, Santa Barbara. The conference accepted 33 papers from 211 submissions, with each paper receiving at least three independent reviews. The proceedings include updated versions of these papers, revised by the authors with comments from reviewers. The conference featured two invited lectures: Victor Shoup's talk on chosen ciphertext security and Susan Landau's talk on security, liberty, and electronic communications. The proceedings also include a Rump Session chaired by Stuart Haber, but these presentations are not included. The conference was successfully managed with the help of a web-based submission server and review server, as well as the support of external reviewers and program committee members. The proceedings cover a wide range of topics in cryptography, including linear cryptanalysis, group signatures, bilinear maps, hash collisions, secure computation, and more. The volume includes 33 papers, each presenting original research in the field of cryptography. The authors are listed in the author index.The 24th Annual International Cryptology Conference (Crypto 2004) was held in Santa Barbara, California, from August 15-19, 2004. It was sponsored by the International Association for Cryptologic Research (IACR) in cooperation with the IEEE Computer Society Technical Committee on Security and Privacy and the Computer Science Department of the University of California, Santa Barbara. The conference accepted 33 papers from 211 submissions, with each paper receiving at least three independent reviews. The proceedings include updated versions of these papers, revised by the authors with comments from reviewers. The conference featured two invited lectures: Victor Shoup's talk on chosen ciphertext security and Susan Landau's talk on security, liberty, and electronic communications. The proceedings also include a Rump Session chaired by Stuart Haber, but these presentations are not included. The conference was successfully managed with the help of a web-based submission server and review server, as well as the support of external reviewers and program committee members. The proceedings cover a wide range of topics in cryptography, including linear cryptanalysis, group signatures, bilinear maps, hash collisions, secure computation, and more. The volume includes 33 papers, each presenting original research in the field of cryptography. The authors are listed in the author index.