Research On Certificateless Threshold Proxy Re-signature In The Standard Model

Threshold Proxy resignature mechanism can not only prevent the signature rightsof the agent over-concentration of the abuse, but also ensure the security and integrityof re-signing key.Threshold proxy re-signature schemes are mostly based on the certificate oridentity,which suffer from either the complexity of key escrow problem or certificatemanagement. Certificateless public key cryptosystem solve the co mplexity ofcertificate management and key escrow problem, is more efficient than traditional PKIpublic key cryptography system, is more secure than the identity-based public keycryptosystem. Therefore, it has broad application prospects in the environme ntalconditions of the mobile devices, wireless sensor networks that require low bandwidthand low processing capacity.Firstly, a certificateless threshold proxy re-signature scheme based oncertificateless public key cryptosystem is designed, the private key generation centercan only generate part of the private key, it can not forge the signature of the legitimateusers, so as to solve the key escrow problem. Secondly, taking into account thecryptosystem provably secure under the random oracle model, when the specific hashfunction replaces the random oracle, the resulted scheme is not completely secure.Therefore, the use of bilinear on the technology and the framework of the standardmodel proposed by Paterson-Schuldt can prove the security of the scheme. Security isbased on the difficulty of solve Type I Type NGBDH problem in polynomial time andthe difficulty of solve Type II Type Many-DH problem in polynomial time. And thescheme is robust, it can tolerate t<n/2agents captured by a malicious attacker,is secureagainst the adaptive chosen message attack.