Abstract: In the broadcast multi-signature scheme like ElGamal, the random parameters can introduce the subliminal channels and cause potential safety problems. Aiming at the problem, a new interactive subliminal-free protocol is designed. The warden cooperates with each signer for generating part signature, and signature center generates multi-signature. The collision-free performance of hash function ensures that the warden can not forge the signatures, so the signature authority of the signer is guaranteed. Compared with the similar protocol, theoretical analysis shows that the proposed protocol is closing the subliminal channel completely and lower in computation complexity and higher in communications efficiency.

Key words: cryptography, broadcast multi-signature, subliminal channel, free protocol, information hiding

摘要： 在ElGamal类广播多重签名方案中，参数的随机性会引入阈下信道，造成安全隐患。针对该问题，设计一个新的交互式阈下信道封闭协议。其中，看守和每个签名者合作生成部分签名，签名中心生成总签名。哈希函数的无碰撞性使看守不能伪造签名，由此保证签名者的签名权力。理论分析证明，与同类协议相比，该协议可以完全封闭阈下信道，且计算复杂度更低，通信效率更高。

关键词: 密码学, 广播多重签名, 阈下信道, 封闭协议, 信息隐藏

CLC Number: 

• TN918