Progress in Cryptology – INDOCRYPT 2025

This book constitutes the refereed proceedings of the 26th International Conference on Cryptology in India, held in Bhubaneshwar, India, during December 14-17, 2025.The 19 full papers presented in this volume were carefully reviewed and selected from 83 submissions. They are organized into these topical sections: Classical Algorithms;  Symmetric-Key Cryptography; Zero-Knowledge and Interactive Proofs; Isogeny-based Cryptography; Multivariate and Lattice-based Cryptography;  Quantum Cryptography; and  Secret Sharing and Cloud Security.