标准模型下安全基于身份代理签密方案

针对现实中代理签密的安全问题，提出一种基于Gu等（GU K, JIA W J, JIANG C L. Efficient identity-based proxy signature in the standard model. The Computer Journal, 2013:bxt132）代理签名的标准模型下可证安全的基于身份代理签密方案。代理签密允许原始签密者授权签密能力给代理签密者，后者能够代表前者生成密文。该方案通过结合基于身份签密和代理签名，既保持了基于身份签密的优点，又具有代理签名的功能。分析表明，基于Diffie-Hellman问题假设下，所提方案满足机密性性和不可伪造性。与已知方案相比，代理密钥生成算法和代理签密算法中各需要2个对运算和1个对运算，方案效率更高。

Secure identity-based proxy signcryption scheme in standard model

Concerning the proxy signcryption security problem in reality, motivated by Gus proxy signature scheme (GU K, JIA W J, JIANG C L. Efficient identity-based proxy signature in the standard model. The Computer Journal, 2013:bxt132), a new secure identity-based proxy signcyption scheme in the standard model was proposed. Proxy signcryption allowed that the original signcrypter delegated his authority of signcrption to the proxy signcrypter in such a way that the latter could generate ciphertext on behalf of the former. By combining the functionalities of identity-based signcryption and proxy signature scheme, the new scheme not only had the advantage of identity-based signcryption scheme, but also had the function of proxy signature scheme. Analysis results show that, under the assumption of Diffie-Hellman problem, the proposed scheme is confidential and unforgeable. Compared with the known scheme, the scheme requires 2 pairings computation in proxy key generation and 1 pairing computation in proxy signcryption. So it has higher computational efficiency.