In current cloud computing system, large amounts of sensitive data are shared to other cloud users.To keep these data confidentiality, data owners should encrypt their data before outsourcing. We choose proxy reencryp...In current cloud computing system, large amounts of sensitive data are shared to other cloud users.To keep these data confidentiality, data owners should encrypt their data before outsourcing. We choose proxy reencryption(PRE) as the cloud data encryption technique. In a PRE system, a semi-trusted proxy can transform a ciphertext under one public key into a ciphertext of the same message under another public key, but the proxy cannot gain any information about the message. In this paper, we propose a certificateless PRE(CL-PRE) scheme without pairings. The security of the proposed scheme can be proved to be equivalent to the computational DiffieHellman(CDH) problem in the random oracle model. Compared with other existing CL-PRE schemes, our scheme requires less computation cost and is significantly more efficient. The new scheme does not need the public key certificates to guarantee validity of public keys and solves the key escrow problem in identity-based public key cryptography.展开更多
Proxy signature schemes enable an entity to del- egate its signing rights to any other party, called proxy signer. As a variant of proxy signature primitive, proxy multi- signature allows a group of original signers t...Proxy signature schemes enable an entity to del- egate its signing rights to any other party, called proxy signer. As a variant of proxy signature primitive, proxy multi- signature allows a group of original signers to delegate their signing capabilities to a single proxy signer in such a way that the proxy signer can sign a message on behalf of the group of original signers. We propose a concrete ID-based proxy multi-signature scheme from bilinear pairings. The proposed scheme is existential unforgeable against adaptively chosen message and given ID-attack in random oracle model under the computational Diltie-Hellman （CDH） assumption. The fascinating property of new scheme is that the size of a proxy multi-signature is independent of the number of original sign- ers. Furthermore the proposed scheme is simple and com- putationally more efficient than other ID-based proxy multi- signature schemes.展开更多
In this paper, based on the verifiable pair and identity-based threshold cryptography, a novel identity-based （ID-based） threshold decryption scheme （IDTDS） is proposed, which is provably secure against adaptive c...In this paper, based on the verifiable pair and identity-based threshold cryptography, a novel identity-based （ID-based） threshold decryption scheme （IDTDS） is proposed, which is provably secure against adaptive chosen cipbertext attack under the computational bilinear Diffie-Hellman （CBDH） problem assumption in the random oracle. The pubic cheekability of ciphertext in the IDTDS is given by simply creating a signed E1Gamal encryption instead of a noninteractive zero-knowledge proof. Furthermore, we introduce a modified verifiable pairing to ensure all decryption shares are consistent. Our scheme is more efficient in verification than the schemes considered previously.展开更多
基金the National Natural Science Foundation of China(No.61133014)
文摘In current cloud computing system, large amounts of sensitive data are shared to other cloud users.To keep these data confidentiality, data owners should encrypt their data before outsourcing. We choose proxy reencryption(PRE) as the cloud data encryption technique. In a PRE system, a semi-trusted proxy can transform a ciphertext under one public key into a ciphertext of the same message under another public key, but the proxy cannot gain any information about the message. In this paper, we propose a certificateless PRE(CL-PRE) scheme without pairings. The security of the proposed scheme can be proved to be equivalent to the computational DiffieHellman(CDH) problem in the random oracle model. Compared with other existing CL-PRE schemes, our scheme requires less computation cost and is significantly more efficient. The new scheme does not need the public key certificates to guarantee validity of public keys and solves the key escrow problem in identity-based public key cryptography.
文摘Proxy signature schemes enable an entity to del- egate its signing rights to any other party, called proxy signer. As a variant of proxy signature primitive, proxy multi- signature allows a group of original signers to delegate their signing capabilities to a single proxy signer in such a way that the proxy signer can sign a message on behalf of the group of original signers. We propose a concrete ID-based proxy multi-signature scheme from bilinear pairings. The proposed scheme is existential unforgeable against adaptively chosen message and given ID-attack in random oracle model under the computational Diltie-Hellman （CDH） assumption. The fascinating property of new scheme is that the size of a proxy multi-signature is independent of the number of original sign- ers. Furthermore the proposed scheme is simple and com- putationally more efficient than other ID-based proxy multi- signature schemes.
基金Supported by the National Natural Science Foundation of China (60970119, 60803149)the National Basic Research Program of China (973 Program) (2007CB311201)
文摘In this paper, based on the verifiable pair and identity-based threshold cryptography, a novel identity-based （ID-based） threshold decryption scheme （IDTDS） is proposed, which is provably secure against adaptive chosen cipbertext attack under the computational bilinear Diffie-Hellman （CBDH） problem assumption in the random oracle. The pubic cheekability of ciphertext in the IDTDS is given by simply creating a signed E1Gamal encryption instead of a noninteractive zero-knowledge proof. Furthermore, we introduce a modified verifiable pairing to ensure all decryption shares are consistent. Our scheme is more efficient in verification than the schemes considered previously.
