[Resource Topic] 2003/034: On the (In)security of the Fiat-Shamir Paradigm

Welcome to the resource topic for 2003/034

Title:
On the (In)security of the Fiat-Shamir Paradigm

Authors: Shafi Goldwasser, Yael Tauman

Abstract:

In 1986, Fiat and Shamir suggested a general method for transforming secure 3-round public-coin identification schemes into digital signature schemes. The significant contribution of this method is a means for designing efficient digital signatures, while hopefully achieving security against chosen message attacks. All other known constructions which achieve such security are substantially more inefficient and complicated in design.

In 1996, Pointcheval and Stern proved that the signature schemes
obtained by the Fiat-Shamir transformation are secure in the so called `Random Oracle Model’. The question is: does the proof of the security of the Fiat-Shamir transformation in the Random Oracle Model, imply that the transformation yields secure signature schemes in the ``real-world"?

In this paper we answer this question negatively. We show that there exist secure 3-round public-coin identification schemes for which the Fiat-Shamir methodology produces {\bf insecure} digital signature schemes for {\bf any} implementation of the Random Oracle Model' in the real-world’ by a function ensemble.

ePrint: https://eprint.iacr.org/2003/034

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 .