The INDOCRYPT series of conferences started in 2000. INDOCRYPT 2004 was the ?fth one in this series. The popularity of this series is increasing every year. The number of papers submitted to INDOCRYPT 2004 was 181, out of which 147 papers conformed to the speci?cations in the call for papers and, therefore, were accepted to the review process. Those 147 submissions were spread over 22 countries. Only 30 papers were accepted to this proceedings. We should note that many of the papers that were not accepted were of good quality but only the top 30 papers were accepted. Each submission received...