Exploiting Redundant Randomness for Resisting Key Exposure in Encrypted Communication Systems

The exposure possibility of keys poses a great threat to almost all modern cryptography, especially in wireless communications. From the adversary's point of view, a cryptographic key can be considered as a random variable in its key space, whose security level can be measured in terms of randomness. In this article, we propose a highly exposure-resilient framework, which incorporates redundant randomness of key sources into the design of cryptographic systems to resist key exposure in encrypted communications. As hardware costs continue to decrease, the deployment of redundant randomness at the same time to achieve a better security level is affordable in the future. The framework offers a way to protect the privacy of a single key by fusing multiple redundant keys. Analysis and results demonstrate that the proposed scheme can dramatically reduce the secrecy outage probability, and provides an extensible way to enhance the encrypted communication system's resistance to unknown eavesdropping or key exposure.