一种新的P2P数据共享解密授权方案

为了解决P2P网络数据共享中的离线问题，应用LaGrange门限秘密分享体制和零知识证明协议，提出了一种新的基于信任代理平台的时限解密授权方案．采用ElGamal密码体制进行加解密；定义了授权代理协议、授权密钥生成协议和授权解密协议，实现了防欺诈的团体控制的时限解密授权；并提出增补方案，解决了动态更新密钥、增删代理、进行代理信息维护等问题．该方案与现有的时限解密授权方案相比较，在安全性、灵活性、有效性等方面有很大的改善．

A new delegation of the decryption scheme for P2P data sharing

By applying the secret sharing system and the zero knowledge proof protocol,this paper presents a new time constraint delegation of the decryption scheme based on trust agent platforms,which solves the problem that the accessed peer cannot offer instant data when it is offline.This scheme carries out encryption and decryption by using ElGamal cryptography.It defines the delegating-agents protocol,the produce of the delegation-key protocol and the decryption protocol,thus implementing the cheat-resisted and quorum controlled time constraint delegation of decryption.And the new scheme is supplemented to settle the problems of the key being renewed dynamically,the agent being added or deleted and the agent's information being maintained.Compared with the previous time constraint delegation of the decryption scheme,it improves security,flexibility and efficiency.