On the Security of UWB Secret Key Generation Methods against Deterministic Channel Prediction Attacks

Abstract

Generating secret keys in mobile wireless networks is considered a challenging problem where a key management infrastructure is not always available. Recent security methods have shown that secret keys can be generated using Ultra Wide Band (UWB) channels. These solutions rely on relevant channel properties such as reciprocity and spatial decorrelation. Accordingly, the radio channel responses can be used as common information to derive secret keys shared by legitimate parties. However, novel studies in the field of UWB channel prediction have demonstrated that channel profiles could be reliably inferred using for instance Ray-Tracing tools. This paper explores this technique to perform attacks and to evaluate the security of UWB secret key generation methods. The main observation here is that it is difficult for a third party to obtain the exact channel responses; thus to retrieve the secret keys. The robustness of UWB key generation methods then depends on the complexity for attackers to describe precisely the physical environment and on the post processing methods to agree on the same key (i.e., quantization, erroneous bits detection, etc.).