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.

This book constitutes the proceedings of the Second International Conference on Codes, Cryptology and Information Security, C2SI 2017, held in Rabat, Morocco, in April 2017. The 19 regular papers presented together with 5 invited talks were carefully reviewed and selected from 72 submissions. The first aim of this conference is to pay homage to Claude Carlet for his valuable contribution in teaching and disseminating knowledge in coding theory and cryptography worldwide, especially in Africa. The second aim of the conference is to provide an international forum for researchers from academia and practitioners from industry from all over the world for discussion of all forms of cryptology, coding theory and information security.

This book constitutes the proceedings of the First International Conference on Codes, Cryptology and Information Security, C2SI 2015, held in Rabat, Morocco, in May 2015. The 22 regular papers presented together with 8 invited talks were carefully reviewed and selected from 59 submissions. The first aim of this conference is to pay homage to Thierry Berger for his valuable contribution in teaching and disseminating knowledge in coding theory and cryptography in Morocco since 2003. The second aim of the conference is to provide an international forum for researchers from academia and practitioners from industry from all over the world for discussion of all forms of cryptology, coding theory and information security.

This book constitutes the proceedings of the Third International Conference on Codes, Cryptology and Information Security, C2SI 2019, held in Rabat, Morocco, in April 2019. The 19 regular papers presented together with 5 invited talks were carefully reviewed and selected from 90 submissions. The first aim of this conference is to pay homage to Said El Hajji for his valuable contribution in research, teaching and disseminating knowledge in numerical analysis, modeling and information security in Morocco, Africa, and worldwide. The second aim of the conference is to provide an international forum for researchers from academia and practitioners from industry from all over the world for discussion of all forms of cryptology, coding theory, and information security.