Revisiting the Security of Fiat-Shamir Signature Schemes under Superposition Attacks

ePrint Report: Revisiting the Security of Fiat-Shamir Signature Schemes under Superposition Attacks

Quan Yuan, Chao Sun, Tsuyoshi Takagi

The Fiat-Shamir transformation is a widely employed technique in constructing signature schemes, known as Fiat-Shamir signature schemes (FS-SIG), derived from secure identification (ID) schemes. However, the existing security proof only takes into account classical signing queries and does not consider superposition attacks, where the signing oracle is quantum-accessible to the adversaries. Alagic et al. proposed a security model called blind unforgeability (BUF, …

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