Towards Post-Quantum Enhanced Identity-Based Encryption

Abstract

Identity-based encryption (IBE) is a type of public-key encryption (PKE) that employs an identifier as the basis for the encryption mechanism. Thus, the communication parties are able to encrypt messages (or verify signatures) without any prior setup between users or distribution of user certificates. This is especially relevant in many mission critical applications, usually characterized by constrained end-points. MIKEY-SAKKE uses this concept to build a highly scalable protocol able to secure cross-platform multimedia communications. However, MIKEY-SAKKE is based on cryptographic primitives that will be no longer secure when sufficiently powerful quantum computers are built. To this end, this paper presents three contributions. First, it evaluates the performance of MIKEY-SAKKE in constrained embedded devices. Second, it extracts the requirements that post-quantum cryptographic primitives should meet in order to allow a plug-and-play replacement of the threatened security primitives with quantum-secure primitives. Third, it benchmarks the different post-quantum primitives running in the NIST standardization process and analyses their impact on the quantum-secure MIKEY-SAKKE. The results show that none of the NIST finalists perfectly meet all the specified requirements to achieve a post-quantum plug-and-play approach. However, the different combinations of post-quantum KEMs and signature schemes have a range of trade-offs compared to SAKKE and ECCSI, either having slower computation or larger keys and ciphertexts/signatures, or both.