Lattice‐based nominative signature using pseudorandom function

Abstract

A nominative signature (NS) is a cryptographic primitive where two parties collude to produce a signature. It is a user certification system and has applications in a variety of sectors where nominee cannot trust heavily on the nominator to validate the nominee's certificate and only targeted entities are allowed to verify the signature on sensitive data. A new construction for NS from standard assumptions on lattice is provided. The authors’ construction relies on collision-resistant preimage sampleable function and symmetric key primitives like collision-resistant pseudorandom function and zero knowledge proof system ZKB++ for Boolean circuits. The authors provide detailed security analysis and show that their construction achieves security under unforgeability, invisibility, impersonation, and non-repudiation in the existing model. Furthermore, our construction exhibits non-transferability. The security under non-repudiation is achieved in the quantum random oracle model using Unruh transform to ZKB++.