一种基于空中接口和核心网协同的LTE系统密钥推演方法

Cooperative method of key derivation for LTE systems based on radio interface and core network

从窃听方的角度,基于空中接口与核心网协同的思想提出了一种LTE系统密钥推演方法。首先,在实现根密钥同步的基础上,根据空中未加密信息提供的安全算法列表,遍历有限安全算法集;然后,将遍历的安全算法与获取的父密钥共同作为参数,通过密钥生成函数生成空中接口子密钥;最后,通过比对明文和解密密文确定密钥。可行性分析表明,窃听方可以利用该方法推演出空中接口子密钥;误码率小于10-3时,可使密钥推演成功率达到90%以上,具有实际应用意义。

This paper put forward a cooperating method for key derivation based on the idea of combination of radio interface and core network. It produced the radio child-keys according to the security algorithm list provided by plain radio message and obtained parent-key, and decided the fight key by comparing the plain context and the deerypted context. It proves that the correct rate of key derivation is more than 90% in the case that the symbol error rate （SER） is less than 10-3 according to the analysis of feasibility. Therefore it has practical application values.