Acta Metallurgica Sinica(English letters) ›› 2007, Vol. 14 ›› Issue (2): 69-74.doi: 1005-8885 (2007) 02-0069-06

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Identity-based threshold signature and mediated proxy signature schemes

YU Yong; YANG Bo; SUN Ying   

  1. Xidian University
  • Received:2006-09-18 Revised:1900-01-01 Online:2007-06-30


Proxy signature schemes allow an original signer to delegate his signing rights to a proxy signer. However, many proxy signature schemes have the defect which is the inability to solve the proxy revocation problem. In this article, we firstly propose an identity-based threshold signature scheme and show that it has the properties of unforgeability and robustness. In our threshold signature scheme, we adopt such a method that the private key associated with an identity rather than the master key is shared. Then, based on the threshold signature scheme, an identity-based mediated proxy signature scheme is proposed where a security mediator (SEM) is introduced to help a proxy signer to generate valid proxy signatures, examine whether a proxy signer signs according to the warrant, and check the revocation of a proxy signer. It is shown that the proposed scheme satisfies all the security requirements of a secure proxy signature. Moreover, a proxy signer must cooperate with the SEM to generate a valid proxy signature, which makes the new scheme have an effective and fast proxy revocation.

Key words:

identity-based; threshold signature; mediated proxy signature; bilinear pairings

CLC Number: