Relation between verifiable random functions and convertible undeniable signatures, and new constructions

  • Authors:
  • Kaoru Kurosawa;Ryo Nojima;Le Trieu Phong

  • Affiliations:
  • Ibaraki University, Japan;NICT, Japan;NICT, Japan

  • Venue:
  • ACISP'12 Proceedings of the 17th Australasian conference on Information Security and Privacy
  • Year:
  • 2012

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Abstract

Verifiable random functions (VRF) and selectively convertible undeniable signature (SCUS) schemes were proposed independently in the literature. In this paper, we observe that they are tightly related. This directly yields several deterministic SCUS schemes based on existing VRF constructions. In addition, we create a new probabilistic SCUS scheme, which is very compact. The confirmation and disavowal protocols of these SCUS are efficient, and can be run either sequentially, concurrently, or arbitrarily. These protocols are based on what we call zero-knowledge protocols for generalized DDH and non-DDH, which are of independent interest.