Two-Tier Signatures, Strongly Unforgeable Signatures, and Fiat-Shamir without Random Oracles. - Mihir Bellare; Sarah Shoup (IACR Cryptol. ePrint Arch., 2007)

Two-tier signatures from the Fiat-Shamir transform, with applications to strongly unforgeable and one-time signatures. - Mihir Bellare; Sarah Shoup (IET Inf. Secur., 2008)