The two-volume proceedings constitutes the refereed proceedings of the 24th International Conference on Progress in Cryptology, INDOCRYPT 2023, Goa, India, in December 2023. They are organized in topical sections as follows: Part I: Symmetric-key cryptography, Hash functions, Authenticated Encryption Modes;

Secure computation, Algorithm hardness, Privacy.- Threshold-Optimal MPC With Friends and Foes.- Network-Agnostic Perfectly Secure Synchronous Message Transmission Revisited.- Explicit Lower Bounds for Communication Complexity of PSM for Concrete Functions.- Distributed Protocols for Oblivious Transfer and Polynomial Evaluation.- Obfuscating Decision Trees.- Privacy-Preserving Plagiarism Checking.- PURED: A unified framework for resource-hard functions.- Post-quantum cryptography.- Implementing Lattice-Based PQC on Resource-Constrained Processors: A Case Study for Kyber/Saber’s Polynomial Multiplication on ARM CortexM0/M0+.- Algorithmic Views of Vectorized Polynomial Multipliers – NTRU.