基于秘密共享的广播加密方案

现在,越来越多的应用要求广播加密方案的解密算法的计算量尽可能小。针对这一需求,给出了秘密共享在广播加密中的另一种应用,通过预先重构插值份额,从而减少解密时重构的计算量。分析表明,改进后的方案只需对明文进行一次加密,授权用户利用各自私钥就能进行解密,而且解密时只需较小的计算量,并能实现安全地剔除用户、添加用户,而不需要授权用户改变私钥,能抗合谋攻击。     

一个叛逆者追踪方案分析和改进

最近,王青龙等人提出了一种新的基于双线性映射的公钥叛逆者追踪方案,并称该方案具有完全抗共谋性、完全撤销性、完全恢复性和黑盒追踪性等优点.分析了王青龙等人的方案,指出该方案不能实现完全撤销功能,并对王青龙等人的方案进行了改进,提出了一个新的基于双线性映射的叛逆者追踪方案.为了减少存储、计算和通信开销,提出的方案使用多项式和过滤函数构建追踪方案.当发现叛逆者时,提出的方案能够在不更新合法用户密钥的前提下,同时安全撤销多个叛逆者,实现了完全撤销,克服了王青龙等人方案的缺陷.方案的安全性基于离散对数问题和判定Diffie-Hellma问题为困难问题.安全性证明和性能分析表明提出的方案是安全的,能满足完全抗共谋性、完全可恢复性、黑盒追踪性和完会撤销性.同时,就存储、计算和通信开销而言,提出的方案比王青龙等人的方案低.     

带动态撤销的移动自组织网络广播加密方案

In order to support the dynamics of the privileged users with low computation, communication and storage overheads in receivers, a secure broadcast encryption scheme for ad hoc networks based on cluster-based structure is proposed, as Mu-Vmdharajan狆s scheme cannot securely remove sub-scribers with data redundancy. In the proposed scheme, we employ polynomial function and filter functions as the basic means of constructing broadcast encryption procedure in order to reduce computation and shortage overhead. Compared with existing schemes, our scheme requires low computation, communication and storage overheads in receivers and can support the dynamics of the privileged users. Furthermore, our scheme can avoid massive message to exchange for establishing the decryption key between members of the cluster. The analysis of security and performance shows that our scheme is more secure than Mu-Vmdharajan ' s scheme and has the same speed of encryption and decryption as theirs. So our scheme is particularly suitable for the devices with low power setting such as ad hoc networks.