Computational Intelligence in Security for Information Systems

This book constitutes the proceedings of the 18th International Conference, CISIS 2025, held in Salamanca, Spain, during October 16–17, 2025.The 17 full papers included in this volume were carefully reviewed and selected from 36 submissions. The papers cover the following topical sections: Malware & Intrusion Detection; Cryptography & Blockchain Security; and AI Safety, Privacy & Trustworthy Systems.The papers also include the special session: Artificial Intelligence for Protecting the Internet of Things.