可证明安全的基于身份的认证密钥协商协议

Provable Secure ID-Based Authenticated Key Agreement Protocol

提出了一种具有私钥产生中心(private key generator,PKG)前向安全性的基于身份的认证密钥协商协议,协议中给出了一种利用用户双方的长期私钥和临时私钥联合计算共享密钥的方法.在标准模型下证明了协议的安全性,并且分析得出,即使攻击者能够同时获得双方的临时私钥或同时获得双方的长期私钥,共享密钥仍然是安全的.性能分析表明,该协议较好地平衡了计算复杂度和安全性这两个协议评价指标.

Key agreement protocols are fundamental to establish communications between two or more parties over an insecure network. Authenticated key agreement protocols not only allow parties to compute the session key but also ensure the authenticity of the involved parties. The design of ID- based authenticated key agreement protocols, which are secure and efficient, remains an open question in the field of ID-based cryptography. In recent years, several ID-based two-party authenticated key agreement protocols have been proposed. However, we discover that these protocols are in fact insecure if the attacker has stronger ability of revealing the ephemeral private keys of parties. In this paper, a new ID-based two-party authenticated key agreement protocol is presented which possesses attribute of PKG forward security. In this protocol, the session key is calculated by the long-term private keys and ephemeral private keys of parties. It is provable secure under q-augmented bilinear Diffie-Hellman exponent （q-ABDHE） assumption in standard model. Analysis shows that the session key is also secure even if the attacker gets the long-term private keys or ephemeral private keys of parties. Compared with other protocols from security and performance, our protocol has a good balance between computational cost and security.