Evaluating Post-Quantum Cryptography in DNSSEC Signing for Top-Level Domain Operators

Like all other digital systems, the Domain Name System (DNS) needs to remain secure, even when future quantum computers are built. This means that DNS operators need to understand the implications of replacing the currently deployed cryptographic algorithms of the DNS Security Extensions (DNSSEC) with post-quantum cryptography (PQC) ones, which are vastly different. We therefore empirically analyze the signing performance of promising PQC algorithms MAYO-2 and Falcon-512 from a DNS operator point of view, in terms of zone file size, signing time, and validation time, and compare them to currently deployed algorithms RSA-1280 and ECDSA-P256. In our experiments, we use a PQC-enhanced DNSSEC signer, the zone files of three country code Top-Level Domains (ccTLDs) of different sizes, and two different CPU models to measure the effects of CPU optimizations. We find that the DNSSEC signing performance of MAYO-2 is better than RSA-1280, while Falcon-512 performs similarly. The validation performance of MAYO-2 is better than ECDSA-P256 and comparable to RSA-1280, whereas Falcon-512 is 0.3 times slower than ECDSA-P256. These results suggest that DNSSEC signing with MAYO-2 and Falcon-512 is feasible for TLD operators. However, Falcon-512 generates larger signature size and MAYO-2 has larger public keys. These drawbacks should be studied further to assess their operational impact on the validation side, for example by studying the behavior of DNS resolvers with PQC algorithms.