Certificate-based Proxy Signature And Certificate-based Blind Signature

Certificate-based public key cryptology(CB-PKC) not only simplifies certificatemanagement in traditional public key cryptology, but also solves key-escrow problems inIdentity-based public key cryptology(IB-PKC), it is a promising public key cryptology. Aproxy signature scheme allows original signer to delegate his signing capability to proxysigner; Blind signature allows user to obtain valid signature of a message such that signerlearns neither the message nor the resulting signature. Both proxy signature and blind signturecan be commonly applied on modern e-commerce systems.This paper constructs a short provably secure certificate-based digital signature(CBS).The resulting signature of the proposed CBS scheme only has one group element, and can beproved secure in the strong secure model. An efficient provable CBS scheme is proposed, inwhich signature algorithm only needs one bilinear pre-operations and the verify process onlyneeds one bilinear operation. Then this paper proposes the formal definition ofcertificate-based proxy signature and secure model, constructs a concrete certificate-basedproxy signature from efficient CBS proposed by our paper. In random oracle model, we provethe security of certificate-based proxy signature. Furthermore, this paper definescertificate-based blind signature scheme and secure model, a certificate-based blindsignature(CBBS) scheme is constructed by using above short certificate-based signaturewhich is proved secure in random oracle model, our CBBS scheme only needs one roundinteraction.