POST-QUANTUM SIGNATURE SCHEME USING BIOMETRICS OR OTHER FUZZY DATA

摘要

Cryptographic methods and systems are described. An example cryptographic system may include a signature engine to digitally sign a message using fuzzy data associated with a signee. The signature engine is configured to generate a digital signature using a lattice instantiation and a linear sketch. The linear sketch is configured based on the lattice instantiation. The digital signature is a function of the fuzzy data and the message and uses a signature-time signing key residing within a signing key space. The signing key space is a space defined by the lattice instantiation. An example of a verification engine is also described. The verification engine is configured to receive the message and the digital signature and to verify the message as signed by the signee. The verification engine is configured to obtain key data for the signee comprising at least an initialisation-time verification key, to compute a distance metric based on the key data and the received digital signature, the distance metric indicating a measure of difference for the signature-time verification key, and to indicate a verification failure responsive to the distance metric being greater than a predefined homomorphic threshold. The methods and systems may be used as an authentication mechanism.