Post-Quantum Cryptography: Current state and quantum mitigation

This study provides an overview of the current state of affairs on the standardization process of Post-Quantum Cryptography (PQC). It presents the 5 main families of PQ algorithms; viz. code-based, isogeny-based, hash-based, lattice-based and multivariate-based. It also describes the NIST Round 3 finalists for encryption and signature schemes, as well as the alternative candidate schemes. Given that the NIST process will still run for a few years, the last chapter offers 2 proposals that system owners can implement now in order to protect the confidentiality of their data against a quantum capable attacker; namely hybrid implementations that use a combination of pre-quantum and post-quantum schemes, and the mixing of pre-shared keys into all keys established via public-key cryptography.