可验证多次使用动态门限大秘密共享方案

Verifiable Multi-Use Dynamic Threshold Large Secret Sharing Scheme

针对大秘密共享存在效率和安全方面的不足,提出一个可验证多次使用动态门限大秘密共享方案.为了提高效率,将大秘密分解,且表示为较小有限域上的矩阵,并利用了二元单向函数.为了增强安全性,推广门限动态调整方法,利用了椭圆曲线群上离散对数.理论分析结果表明,该方案不仅存储等效率大大提高,还能抵抗不诚信参与者攻击,且重建过程中秘密份额始终保密无须更新.尤其当参与者信任发生变化或参与者人数变动时,门限值能够被t个可信参与者及时调整.

For the efficiency and security problems of large secret sharing,a verifiable multi-use dynamic thres hold large secret sharing scheme was put forward. To improve the efficiency,the large secret is divided and represented as a matrix over smaller finite field,and the two-variable one-way function is also utilized; to enhance security,the thres hold modification method is slightly expanded and the elliptic curve discrete logarithm problem is employed. By analysis,this new scheme not only is high-efficiency,but also can prevent dishonest participants from cheating. Meanwhile,the secret shadows can always be kept secret and need not to be renewed in the process of reconstruction. Especially,when the mutual trust varies or the number of the participants belonging to an organization fluctuates,the threshold value will be adjusted by at least t credible participants in time.