New Publication: Post-quantum Signatures Memory & Bandwidth Efficiency

The paper “Scaling of Memory and Bandwidth Requirements of Post-quantum Signatures with Message Size”, published in Migration and Agility in Cryptographic Systems, analyses the qualitative memory and bandwidth efficiency of currently standardised post-quantum signature schemes and their protocol integrations, mainly in the X.509 context.

A particular focus is placed on the extent to which the different signature algorithms support streaming (online computations) with respect to the signed message during signing and verification. The paper also reviews whether a short message representative can be pre-computed outside the cryptographic module responsible for the signing or verification operation.

In addition, the work provides a review of the corresponding cryptographic API for PKCS#11 version 3.2, which introduces numerous post-quantum signature algorithms.

The analysis shows that, for specific realistic use cases, the qualitative memory and bandwidth efficiency of post-quantum signature schemes in protocol use can vary widely and tends to be substantially degraded compared with traditional signature schemes based on RSA and elliptic curves. These traditional schemes always allow a short message representative to be pre-computed in the form of a hash value.

The results provide relevant insights for the PQC migration of existing applications that currently use traditional RSA- or elliptic-curve-based signature schemes.