基于身份的新型广播签密方案

Novel Identity Based Broadcast Signcryption Scheme

为了适应当前信息传输环境的多样性及多变性,保证传输信息的机密性及权威性,通过借鉴签密方案的优势并结合广播加密模型,提出一种新的身份型广播签密方案。该方案使用哈希运算、环和运算、双线性对运算等多种运算形式,使得新方案中公、私钥长度保持不变,密文长度等于接收用户的个数加1,签密过程与解签密过程均无需双线性对运算,因此具有较低的运算代价及存储代价。详细的安全性证明显示该方案的机密性可归约为弱的BCDH问题,不可伪造性可归约为PSG签名问题,从而使该方案能应用于安全性和实用性要求较高的环境。

A novel identity based broadcast signcryption scheme was proposed to satisfy the diversity and changeability of the current data transmission environment, and guarantee the confidentiality and authority of the transferred informa- tion using the integration of the broadcast encryption, the identity-based cryptography and the signcryption. By means of this scheme, taking the various arithmetic operation such as hash, ring add and bilinear pairing et al. , the size of cipher- text is equal to the number of the receiver adding one, and the size of public or private key keeps constant. Simultane ously, the process of signcryption or unsigncryption needs not bilinear pairing operation with high computational cost and storage cost. The detailed proof of security shows that the proposed scheme is not only to be IDN-CCA2 secure un- der the weak BCDH problem but also to be existentially unforgeable under the EF-ACMA of PSG proposed by Pater- son. Furthermore, the proposed scheme is efficient and practical at performance.