基于广义猫映射的组播密钥管理方案研究

Study of a Multicast Key Management Scheme Based on the Generalized Cat Map

为处理组密钥管理中的"1影响n问题",曹国梁等人提出了组密钥与个体密钥之间存在广义猫映射关系的组播加密算法及其密钥管理方案。我们进一步分析其密码强度、前向/后向保密性和可扩展性问题。解析结果表明:对已知明文攻击的脆弱性使该密码不适合提供组播数据保密性安全服务;通信开销以组规模为渐近下界,使该方案不满足大型组播组中密钥管理低带宽开销的QoS要求。分析方法对其他密码算法转化为组密钥更新协议的研究亦有积极作用。

Aiming to deal with ＂the 1-affects-n problem＂ in group key management, a multicast encryption algorithm and ;ts corresponding key management scheme where there is a relat;on of the generalized cat map between the group key and individual keys were proposed by Cao et al.. We further analyze the cipher strength, forward/backward secre- cy and scalabil;ty problems. The analytical results demonstrate that the cipher is not suitable to provide the security service of multicast data confidentiality due to its vulnerability to the known-plaintext attack, and the scheme does not meet the QoS requirement of low bandwidth overhead for key management in a large multicast group because the group size is an asymptotic lower bound for the communication overhead. The analytical methods will also have positive effect on the research into converting other encryption algorithms into group rekeying protocols.