This book constitutes the revised selected papers from the 24th International Conference on Information Security Applications, WISA 2023, held in Jeju Island, South Korea, during August 23–25, 2023. The 25 papers included in this book were carefully reviewed and selected from 76 submissions. They were organized in topical sections as follows: Cryptography; network and application security; privacy and management; attacks and defenses; post-quantum cryptography and quantum cryptanalysis.