A lightweight white-box symmetric encryption algorithm against node capture for WSNs

Wireless Sensor Networks (WSNs) are often deployed in hostile environments and an adversary can potentially capture sensor nodes. This is a typical white-box attack context, i.e., the adversary may have total visibility of the implementation of the build-in cryptosystem and full control over its execution platform - the sensor nodes. Existing encryption algorithms for white-box attack contexts require large memory footprint and hence are not applicable for wireless sensor networks scenarios. As a countermeasure against the threat in this context, a lightweight secure implementation of the symmetric encryption algorithm SMS4 is proposed. The basic idea of our solution is to merge several steps of the round function of SMS4 into table lookups, blended by randomly generated mixing bijections. Its security and efficiency are analyzed. Evaluation shows our solution satisfies the requirement of sensor nodes in terms of limited memory size and low computational costs.