An Efficient Strong ID-Based Signature Scheme with Unforgeability

Digital signature is an important authentication technique. Most of digital signature schemes don´t satisfy strong unforgeability and only are proven secure in the random oracle model. It is a challenge to construct an ID-based digital signature scheme with strong unforgeability in the standard model. To overcome this problem, in this paper, we propose a strongly unforgeable identity-based signature (IBS) scheme in the standard model whose security is reduced to the hardness of the standard computational Diffie-Hellman problem in bilinear groups. Our IBS needs only one more group element as parameter in order to build a signature, plus original system parameters in the Waters identity-based encryption scheme (IBE) which are used to verify whether the identity is planned by the right owner authorized from the private key generator (PKG). By virtue of smaller number of system parameters against previous schemes of the same kind, our IBS is more suitable for storage and communication requirements. In particular, our IBS covers a stronger security property called strong unforgeability without random oracles.