Post-Quantum Blind Signature Schemes

This work addresses the threat that quantum computers pose to conventional digital signatures. It focuses on remote signing scenarios, specifically in the context of national identification systems such as ID Austria. We propose a new blind signature scheme that is secure against quantum attacks, preserves user privacy, and supports remote signing. The construction uses a commitment scheme and a post-quantum digital signature. We formally define the security model and prove that the scheme satisfies the IND-CMA and EUF-CMA properties. We discuss a specific instance using the Dilithium algorithm and other PQ algorithms. The result is a practically deployable scheme suitable for electronic identification and digital services. A novelty is the combination of blind signatures with post-quantum signatures in a remote signing model and the proof of its security.