[Resource Topic] 2007/273: Two-Tier Signatures, Strongly Unforgeable Signatures, and Fiat-Shamir without Random Oracles

Welcome to the resource topic for 2007/273

Title:
Two-Tier Signatures, Strongly Unforgeable Signatures, and Fiat-Shamir without Random Oracles

Authors: Mihir Bellare, Sarah Shoup

Abstract:

We show how the Fiat-Shamir transform can be used to convert three-move identification protocols into two-tier signature schemes (a primitive we define) with a proof of security that makes a standard assumption on the hash function rather than modeling it as a random oracle. The result requires security of the starting protocol against concurrent attacks. We can show that numerous protocols have the required properties and so obtain numerous efficient two-tier schemes. Our first application is an efficient transform of any unforgeable signature scheme into a strongly unforgeable one, which uses as a tool any two-tier scheme. (This extends work of Boneh, Shen and Waters whose transform only applies to a limited class of schemes.) The second application is new one-time signature schemes that, compared to one-way function based ones of the same computational cost, have smaller key and signature sizes.

ePrint: https://eprint.iacr.org/2007/273

See all topics related to this paper.

Feel free to post resources that are related to this paper below.

Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.

For more information, see the rules for Resource Topics .