C-HIBS:一种组合层次式标识签名算法  

C-HIBS:A Hierarchical Identity-based Signature Algorithm Based on Combined Keys

作　　者：石典佑 王小峰[1] 黄金锋[1] 邢倩倩[1] 陈锦榕 孙兵[1] SHI Dian-You;WANG Xiao-Feng;HUANG Jin-Feng;XING Qian-Qian;CHEN Jin-Rong;SUN Bing(National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学,长沙410073

出　　处：《密码学报》2022年第6期982-1001,共20页Journal of Cryptologic Research

摘　　要：层次式标识签名算法(hierarchical identity-based signature,HIBS)采用分级密钥生成技术实现了可扩展的密钥管理,但现有基于全域哈希构造的层次式标识签名算法存在密钥生成机构(private key generator,PKG)随机私钥难以认证、签名长度随用户标识深度线性增长、不支持离线验签优化的问题.本文提出组合层次式标识签名算法(C-HIBS),增加以组合矩阵为核心的密钥托管机构,实现PKG随机私钥的生成与验证,解决了层次密钥管理健壮性差的问题;设计了扁平的层次式标识签名算法,将签名内容中的椭圆曲线点个数从t+2缩减至2个(其中t为节点所在层级),并支持验签算法中在线双线性对运算次数从t+2降低至2次的离线优化;基于标准的BDH难题假设,在随机预言模型下将困难问题同时嵌入到组合矩阵和层次密钥生成过程,在PKG数量有限和将随机私钥可信保护两种情况下均证明方案具有EU-CMA安全性.Hierarchical identity-based signature(HIBS)realizes scalable key management by hierarchical key generation.However,there are some problems in the hierarchical identity-based signature schemes based on the full-domain hash paradigm,such as the difficulty in authenticating the random private keys issued by the private key generator(PKG),the length of the signature increasing linearly with the depth of the user’s identity,and the lack of support for offline verification optimization.This paper proposes a combined hierarchical identity-based signature scheme(C-HIBS)to solve these problems.By adding a key escrow organization centered on the combination matrix,the process of PKG random private key generation and that of verification are realized,and the problem of poor robustness of hierarchical key management is solved.Furthermore,a flat hierarchical identity-based signature scheme is designed,which reduces the number of elliptic curve points from t+2 to 2 in the signature,where t is the level of the node,and decreases the online bilinear pairing operation from t+2 to 2 in the verification.By embedding some mathematical hard problems both in combination matrix and in hierarchical key generation process based on the standard BDH assumption,the proposed scheme is proved to have EU-CMA security,both in the cases of limited number of PKG and trusted protection of random private keys.

关 键 词：组合 层次式 标识密码 健壮性 离线 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]