Achieving 128-bit Security against Quantum Attacks in OpenVPN

Niederreiter is a candidate post-quantum cryptosystem. Its large public key size currently discourages its use in practice. We demonstrate and evaluate how Niederreiter can be used for quantum-secure key exchanges by implementing it in OpenVPN. We contribute an analysis of how much Grover’s algorithm can speed up existing attacks on Niederreiter and McEliece and what code parameters can protect against these attacks. We provide parameters for 128-bit quantum security that result in almost 35% smaller keys than parameters currently available in literature.