The book constitutes the proceedings of the 28th International Conference on Information Security, ISC 2025, held in Seoul, South Korea, during October 20–22, 2025.

The 28 full papers presented in these proceedings were carefully reviewed and selected from 77 submissions. The papers are organized in the following topical sections: Cryptanalysis and Cipher Security; Network Security; Post-quantum Cryptography; Side-Channel Attacks and Countermeasures; AI Security; Biometric Security; Malware Analysis; Systems Security; Access Control & Privacy; Smart Contracts and Blockchain Security.