Lattice-Based Puncturable Blind Signature Scheme with Bidirectional Security

Lattice-based blind signature ensures that users can generate a signature on a message while interacting with the signer without revealing any information about the message, and resists quantum attacks. However, the existing lattice-based blind signature schemes did not fully address the threat of key exposure, lacking in their provision for both forward and backward security. In this paper, we propose a lattice-based puncturable blind signature (PBS) scheme that employs puncturable pseudorandom functions to achieve bidirectional security. The implementation of puncturing technique not only enables fine-grained revocation of signing capabilities, effectively safeguarding against key leakage attacks and thereby ensuring bidirectional security, but also markedly decreases the computational complexity involved in key updates, reducing it from O(n) to O(1). Furthermore, the security of the proposed PBS scheme under the SIS hard assumption is validated in the random oracle model.