关键词: 门限签名, 中国剩余定理, 移动攻击, 更新私钥, 成员加入

Abstract: Abstract: To resist the mobile attacks, the paper proposed a dynamic threshold signature scheme based on Chinese Remainder Theorem. Firstly，members exchanged their shadows to generate their private keys and the group public key. Secondly, the partial signature was generated by cooperation. Finally, the partial signature was used to synthesize the signature. The scheme does not expose the group private key in the signature process, so that the group private key can be reused. The members updated their private keys periodically without changing the group public key to ensure that the signature before update is still valid. Besides, the scheme allows new members to join while keep the old member’s private keys and group private key unexposed. The scheme has forward security, which can resist the mobile attacks effectively. Theoretical analysis and simulation results show that, compared with the proactive threshold RSA scheme proposed by Xu Fu, the updating time consumption and signature time consumption of the scheme are constant, the scheme has higher time efficiency.

Key words: threshold signature, Chinese Remainder Theorem(CRT), mobile attacks, update private key, member expansion