This book constitutes the refereed proceedings of the 22nd International Conference on Cryptology in India, INDOCRYPT 2021, which was held in Jaipur, India, during December 12-15, 2021. The 27 full papers included in these proceedings were carefully reviewed and selected from 65 submissions. They were organized in topical sections as follows: authenticated encryption; symmetric cryptography; lightweight cryptography; side-channel attacks; fault attacks; post-quantum cryptography; public key encryption and protocols; cryptographic constructions; blockchains.

This book constitutes the refereed proceedings of the 4th International Conference on Codes, Cryptology and Information Security, C2SI 2023, held in Rabat, Morocco, during May 29–31, 2023. The 21 full papers included in this book were carefully reviewed and selected from 62 submissions. They were organized in topical sections as follows: Invited Papers, Cryptography, Information Security, Discrete Mathematics, Coding Theory.