Quantum-safe Encryption: A New Method to Reduce Complexity and/or Improve Security Level

TL;DR

This paper introduces novel techniques to improve quantum-safe encryption schemes inspired by McEliece, focusing on reducing complexity and enhancing security through masking, randomness, and error correction methods.

Contribution

It presents new methods for key masking, incorporating randomness without extra public info, and efficient error correction, advancing post-quantum cryptography.

Findings

Larger keys with lower complexity are achievable.

Enhanced security by increasing attack difficulty.

Efficient key recovery with negligible decoding complexity.

Abstract

This work presents some novel techniques to enhance an encryption scheme motivated by classical McEliece cryptosystem. Contributions include: (1) using masking matrices to hide sensitive data, (2) allowing both legitimate parties to incorporate randomness in the public key without sharing any additional public information, (3) using concatenation of a repetition code for error correction, permitting key recovery with a negligible decoding complexity, (4) making attacks more difficult by increasing the complexity in verifying a given key candidate has resulted in the actual key, (5) introducing memory in the error sequence such that: (i) error vector is composed of a random number of erroneous bits, (ii) errors can be all corrected when used in conjunction with concatenation of a repetition code of length 3. Proposed techniques allow generating significantly larger keys, at the same time, with a much lower complexity, as compared to known post-quantum key generation techniques relying on randomization.