This book constitutes the revised selected papers of the 19th International Conference on Risks and Security of Internet and Systems, CRiSIS 2024, held in Aix-en-Provence, France, during November 26-28, 2024. The 32 full papers and 2 short papers presented here were carefully selected and reviewed from 90 submissions. These papers have been organized in the following topical sections: Security Network Protocols; AI-Driven Threat Detection; Information Security Management; Applied Cryptography & Privacy; Threats Detection & Protection; Risk Identification & Management; Blockchain & Distributed Ledger Security; AI for Security Assessment.