One-more assumptions do not help fiat-shamir-type signature schemes in NPROM

Abstract

On the Fiat-Shamir-type signature schemes, there are several impossibility results concerning their provable security. Most of these impossibility results employ the non-programmable random oracle model (NPROM), and to the best of our knowledge, all impossibilities deal with the security reductions from the non-interactive cryptographic assumptions except for the result on the security of Schnorr signature scheme from the One-More DL (OM-DL) assumption in ProvSec2017. In this paper, we extend the impossibility result above concerning Schnorr signature scheme and the OM-DL assumption to a wider class of the Fiat-Shamir-type signature schemes, and aim to find out the conditions so that such impossibility results hold. We show that a specific class of the Fiat-Shamir-type signature schemes, including Schnorr signature scheme, cannot be proven to be euf-cma secure in NPROM from the generalized One-More cryptographic assumptions. This is just a generalization of the impossibility concerning Schnorr signature scheme and the OM-DL assumption. Our result also suggests that for some Fiat-Shamir-type signature schemes, which is not covered by our impossibility (e.g. the RSA-based schemes), there may exist a successful security proof in NPROM from the interactive cryptographic assumption.