HybridPKE: A forward-secure non-interactive quantum-safe hybrid key exchange scheme

Abstract

The schemes submitted to NIST call for standardization of post-quantum cryptography have some common drawbacks in terms of decryption failure probability, scalability, and switching issues from pre-quantum to post- quantum cryptography. In this paper, we address all these issues and propose a novel quantum-safe scheme HybridPKE for key exchange and encryption. HybridPKE is based on Ring Learning with Error lattice problem and uses Advance Encryption Standard symmetric-key algorithm. The scheme is non-interactive as both the parties establish the same key without sharing any reconciliation information. HybridPKE provides forward secrecy and authenticated quantum-safe communication with zero decryption failure. The uniqueness of this paper lies in thefirst to integrate both pre-quantum and post-quantum scheme to provide a robust hybrid key exchange. The paper presents the efficient implementation and supported parameter set of purposed HybridPKE scheme by fine-tuning the parameters through rigorous experimentation and security analysis under different attacks.