This book constitutes the refereed proceedings of the 27th International Conference on Information Security and Cryptology on Information Security and Cryptology - ICISC 2024, held in Seoul, South Korea, during November 20-22, 2024. The 23 full papers included in this book were carefully reviewed and selected from 58 submissions. They were organized in topical sections as follows: cryptanalysis of block ciphers; signature schemes; applied cryptography; quantum cryptography and deep learning based analysis; side-channel and automotive attack; cyber security; and AI security.