Cryptography algorithm can be reduced to solve difficult mathematical problems in the standard model (without random oracle assumption). In order to overcome the problem that in the standard model, an existed identity-based partially blind signature (IBPBS) scheme does not prevent a tampering, an enhanced IBPBS scheme was put forward. The original algorithm was improved by the enhanced scheme in two ways. One was to adopt an implicit signature which effectively prevented the entities who were involved in the signature tampering the public information. The other was to avoid using additional supplementary protocols. Based on the standard model of signature mentioned by Paterson et al, a standard model of IBPBS was defined. The enhanced IBPBS scheme was reduced to resolve the CDH problem on an elliptic curve in the standard model, and was proved to achieve the unforgeability and the unlinkability. Comparative analysis showed that the new IBPBS scheme wins enhanced security, lower computational overhead and lower algorithm overhead, and can be used to build secure protocols on electronic cash or electronic voting as well.
