Highly adaptive cryptographic suites for autonomic WSNs

This paper presents a novel approach to support flexible cryptographic suites on resource restricted devices. Common primitives which are used for symmetric key algorithms have been thoroughly analysed by the hardware and cryptography community to design more efficient implementations. A side product of this development and a common fact for cryptographers is the strong modularisation of block ciphers and the similarities therein. This contribution shows how an efficient combination framework can exploit these characteristics to support a large variety of cryptographic primitives on resource restricted hardware. We present a collection of basic building blocks, which can be combined dynamically to implement various primitives. With the high energy consumption of radio transmission in mind the presented work takes a different direction from existing approaches which aim at highly optimised primitives. By exploiting the modular redundancy within existing block ciphers the presented approach can adapt to a node context and choose the primitives optimal for a specific task in terms of security requirements, and resource consumption. This work additionally discusses how this modularity enables a device to efficiently update existing and install new primitives, and how it may adapt implementations to resource restricted execution environments.