Abstract: Aiming at the problem that many proxy signature schemes can’t provide confidentiality，a new multi-proxy signcryption scheme with shared unsigncryption is proposed in this paper，which is based on the elliptic curve cryptology.The new scheme has the following advanced properties：（1）It provides authentication and confidentiality.（2）The proxy signcrypters and receivers can respectively generate their group keys by themselves with the knowledge proof protocol of double discrete logarithm based on elliptic curve，so it doesn’t need CA to distribute for them.（3）In the scheme，any t or more of n proxy signcrypters can signcrypt a message and any t-1 or fewer proxy signcrypters can’t signcrypt a message，any l or more of m receivers can unsigncrypt the message and any l-1 or fewer receivers can not unsigncrypt the message.（4）The system doesn’t need a security channel and the cost of the system can be lowed.

Key words: multi-proxy signature, signcryption, the elliptic curve, shared unsigncryption

摘要： 针对很多代理签名方案不能实现保密性的问题，基于椭圆曲线密码体制提出了一种新的带共享解密的多重代理签密方案。新方案具有如下优点：（1）同时实现了认证性和保密性。（2）代理签密者和接收者利用基于椭圆曲线双重离散对数证明协议自己计算代理群私钥和接收群私钥，而不需要CA为其分发。（3）代理签密和共享解密的实现分别是一个（t，n）门限和（l，m）门限秘密分享方案。（4）整个通信不需要安全信道，从而降低了通信的代价。

关键词: 多重代理签名, 签密, 椭圆曲线, 共享解密