darmstadt.de When deploying wireless sensor networks (WSNs) in pub-lic environments it may become necessary to secure their data storage and transmission against possible attacks such as node-compromise and eavesdropping. The nodes feature only small computational and energy resources, thus requir-ing efficient algorithms. As a solution for this problem the TinyPEDS approach was proposed in [7], which utilizes the Elliptic Curve ElGamal (EC-ElGamal) cryptosystem for ad-ditive homomorphic encryption allowing concealed data ag-gregation. This work presents an optimized implementation of EC-ElGamal on a MicaZ mote, which is a typical sensor node platform with 8-bit processor for WSNs. Compared to the best previous result, our implementation is at least 44% faster for fixed-point multiplication. Because most parts of the algorithm are similar to standard Elliptic Curve algo-rithms, the results may be reused in other realizations on constrained devices as well
