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.