How to strengthen any weakly unforgeable signature into a strongly unforgeable signature

Ron Steinfeld*, Josef Pieprzyk, Huaxiong Wang

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

39 Citations (Scopus)

Abstract

Standard signature schemes are usually designed only to achieve weak unforgeability - i.e. preventing forgery of signatures on new messages not previously signed. However, most signature schemes are randomised and allow many possible signatures for a single message. In this case, it may be possible to produce a new signature on a previously signed message. Some applications require that this type of forgery also be prevented - this requirement is called strong unforgeability.

At PKC2006, Boneh Shen and Waters presented an efficient transform based on any randomised trapdoor hash function which converts a weakly unforgeable signature into a strongly unforgeable signature and applied it to construct a strongly unforgeable signature based on the CDH problem. However, the transform of Boneh et al only applies to a class of so-called partitioned signatures. Although many schemes fall in this class, some do not, for example the DSA signature. Hence it is natural to ask whether one can obtain a truly generic efficient transform based on any randomised trapdoor hash function which converts any weakly unforgeable signature into a strongly unforgeable one. We answer this question in the positive by presenting a simple modification of the Boneh-Shen-Waters transform. Our modified transform uses two randomised trapdoor hash functions.

Original languageEnglish
Title of host publicationTopics in Cryptology
Subtitle of host publicationCT-RSA 2007 - The Cryptographers Track at the RSA Conference 2007, Proceedings
EditorsMasayuki Abe
Place of PublicationBerlin; Heidelberg
PublisherSpringer, Springer Nature
Pages357-371
Number of pages15
ISBN (Print)9783540693277
Publication statusPublished - 2007
EventCryptographers Track at the RSA Conference, CT-RSA 2007 - San Francisco, United States
Duration: 5 Feb 20079 Feb 2007

Publication series

NameLecture Notes in Computer Science
PublisherSpringer-Verlag Berlin
Volume4377
ISSN (Print)0302-9743

Other

OtherCryptographers Track at the RSA Conference, CT-RSA 2007
CountryUnited States
CitySan Francisco
Period5/02/079/02/07

Keywords

  • digital signature
  • strong unforgeability
  • trapdoor hash function
  • provable security
  • transform

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