Digital stream can be easily wiretapped, intercepted, modified, forged, and replayed. Therefore, the most importent task for information security is how to keep confidentiality, integrity, availability, controllability, and accountability for digital information. As the case may be, we can adopt different way to protect the information's integrity, such as signature, integrity check, and authentication on identity.Key escrow is an inherent disadvantage for traditional ID-based cryptosystem, for example, the dishonest PKG can forge the signature of any user on the other hand. The user can deny the signature actually signed by him/herself. To avoid the key escrow problem, we describe an ID-based signature scheme without trusted Private Key Generator (PKG). There still needs a PKG in our scheme to generate the private key of the user, but the user can keep their private key secret from knowing by PKG, because the private key embeds some particular information chosen by the user. If the dishonest PKG impersonate an honest user to sign a message, the user can provide this particular information to verify the dishonest of the PKG.Certificateless Public Key Cryptography (CL-PKC) eliminates the inherent key escrow problem of ID-based cryptography, while preserving the attractive advantage of cryptography which dispenses with certificates of traditional Public Key Cryptography (PKC). In this paper, we make use of a short CLS scheme that is proved to be secure in the random oracle model under the hardness assumption of k-CAA and Inv-CDHP,validate the length of our scheme is 160 bits. Based on the respective analysis of the advantages and disadvanrages of identity-based cryptography (ID-PKC) and certificateless public key cryptography (CL-PKC) introduces a certificateless authentication in hybrid P2P network. The scheme overcomes the problem of complicated management of PKI certificates and the key escrow of ID-PKC in P2P network.It speeds up the time of bidirectional authenticated and key agreement protocols,proved to be more efficient,and can better solve the security problems in the hybrid P2P network. |