International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: More short signatures without random oracles

Victor K. Wei
Tsz Hon Yuen
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Abstract: We construct three new signatures and prove their securities without random oracles. They are motivated, respectively, by Boneh and Boyen's, Zhang, et al.'s, and Camenisch and Lysyanskaya's signatures without random oracles. The first two of our signatures are as short as Boneh and Boyen's (resp. Zhang, et al.'s} state-of-the-art short signatures. Our third signature is reducible to a modified LRSW Assumption but without their hypothesized external signing oracle. New and interesting variants of the q-SDH Assumption, the q-SR (Square Root) Assumption are also presented. New and independently interesting proof techniques extending the two-mode technique of Boneh and Boyen are used, including a combined three-mode simulation and rewinding in the standard model.
  title={More short signatures without random oracles},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / signature},
  note={Accepted by International Journal of Network Security, ISSN 1816-353X  (Print) ,  ISSN 1816-3548  (Online) 13191 received 20 Dec 2005, last revised 11 Feb 2006},
  author={Victor K. Wei and Tsz Hon Yuen},