中文摘要：

针对L-P虚拟企业安全交互模型进行了深入分析，指出该方案由于没有考虑到RSA密钥结构的特殊性，直接在整数模φ（N）剩余类环Zφ（N）上实现分布式门限签名，因此存在代数构造问题．在此基础上，对L—P方案进行修正和改进，通过引入参数π并将环Zφ（N）中部分运算转换到整数环Z上，从而有效避免了环Zφ（N）中求逆及秘密参数泄露问题．理论分析证明：新方案为基于门限RSA签名机制实现虚拟企业的安全交互提供了正确可行的算法模型．

英文摘要：

In this paper, the VCA interaction scheme for VE presented by Liu and Pan （for short, L- P scheme） is firstly analyzed, and it is found that a plain secret sharing method was directly used to construct the threshold RSA signature and the key distribution algorithms in the ring Zφ（N） , which inevitably causes some algebraic construction flaws, i. e. incalculableness of elements＇ inverses, unexpected decomposition of the module N, and the leakage of system secrets. In order to remedy L- P scheme＇s drawbacks, a new improved scheme is then presented, in which a new parameter n is introduced to avoid computing of some particular elements＇ inverses in the ring Zφ（N） since it is the multiple of these elements. And consequently the important parameter exp can be computed in the integer ring Z other than the residue ring Zφ（N） since it is the exponential component in the function of SIG which is in ZN. Analysis shows that the new scheme can effectively avoid any inverse＇s computing in any ring, and can furthermore avoid the unexpected decomposition of the module N and the leakage of secret parameters. In addition, the proposed scheme is more efficient than the L-P scheme in the VCA sub-keys redistribution stage. Therefore, the new improved scheme provides a correct and feasible VCA interaction model for VE based on RSA threshold signature mechanism.