Paper 2014/311

Exponent-inversion Signatures and IBE under Static Assumptions

Tsz Hon Yuen, Sherman S. M. Chow, Cong Zhang, and Siu Ming Yiu


Boneh-Boyen signatures are widely used in many advanced cryptosystems. It has a structure of ``inversion in the exponent", and its unforgeability against $q$ chosen-messages attack is proven under the non-static $q$-Strong Diffie-Hellman assumption. It has been an open problem whether the exponent-inversion signature, and its various applications, can be proved based on a weaker static assumption. We propose a dual-form Boneh-Boyen signature and demonstrate how to prove the security for the exponent-inversion signature structure in the standard model under static assumptions. We apply our proof technique to a number of related cryptosystems employing similar structure, including anonymous credentials, identity-based encryption (IBE) and accountable authority IBE. Our results give the first exponent-inversion IBE in the standard model under static assumption. Our anonymous credentials and accountable authority IBE are also better than existing schemes in terms of both security and efficiency.

Available format(s)
Public-key cryptography
Publication info
Preprint. MINOR revision.
Dual form signatureIdentity-based encryptionExponent inversionStrong Diffie-HellmanAnonymous credentialsBlack-box accountability
Contact author(s)
johnyuenhk @ gmail com
czhang2 @ cs hku hk
sherman @ ie cuhk edu hk
2014-05-01: received
Short URL
Creative Commons Attribution


      author = {Tsz Hon Yuen and Sherman S. M.  Chow and Cong Zhang and Siu Ming Yiu},
      title = {Exponent-inversion Signatures and IBE under Static Assumptions},
      howpublished = {Cryptology ePrint Archive, Paper 2014/311},
      year = {2014},
      note = {\url{}},
      url = {}
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