Post-quantum signature scheme using biometrics or other fuzzy data

Abstract

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.

Description

technical field

[0001] The present invention relates to cryptographic methods and systems. In particular, the invention relates to the configuration of digital signatures based on obfuscated data inputs. The methods and systems can be used to authenticate users and enable secure communications between two computing devices. Background technique

[0002] Public key cryptography plays an important role in enabling secure communications between digital devices. For example, public-key cryptography is the basis for modern electronic commerce, secure messaging, online banking, and access to remote computing systems. In many cryptographic schemes, a user is provided with a private key and a public key. The private key is kept secret and can be used to sign digital messages. The public key can be distributed widely and then used to verify that a message was signed with that private key. In this way, the pair of keys is able to authenticate the user by verifying the message as ...

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