This volume LNCS 14217 constitutes the refereed proceedings of the 17th International Conference on Provable and Practical Security, ProvSec 2023, held in Wuhan, China, during October 2023. The 20 full papers presented together with 3 short papers were carefully reviewed and selected from 71 submissions. The conference focuses on Fundamentals & Cryptographic Primitives; Cryptanalysis; Signature; Encryption; Privacy Preservation; and Blockchain Security.