This book constitutes the proceedings of the 19th International Conference on Provable and Practical Security, ProvSec 2025, which took place in Yokohama, Japan, during October 10-12, 2025.

The 22 full papers, 3 short papers and 5 posters included in this book were carefully reviewed and selected from 72 submissions. They were organized in topical sections as follows: digital signature; post-quantum cryptography; machine learning security and privacy; cryptographic protocol; searchable encryption; cryptanalysis; distributed system and blockchain security; short papers; and posters. set programming; functional programming; languages, methods and tools; and declarative solutions.