This book constitutes the refereed proceedings of the 21st International Conference on Information Security Practice and Experience, ISPEC 2026, held in Xi’an, China, during November 6–8, 2026. The 35 full papers included in these proceedings were carefully reviewed and selected from 101 submissions. They were organized in the following topical sections: Cryptographic Protocols; Cryptographic Primitive; Cryptographic Foundation; Cryptanalysis; AI Security; Federated Learning; Cybersecurity and Intrusion Detection ; Malware Analysis and Software Security.
