Power grid networks, that use symmetric ciphers for secured communication, need some system for key distribution. It might be a special secured channel or a method which allows key-distribution via public channel. The public channel method could be done with asymmetric ciphers, but the growing computing and power requirements of modern ciphers are problematic for low-power devices, which are used in this kind of networks and which should provide sufficient security for communication. This article deals with the implementation of the Diffie-Hellman algorithm over elliptic curves for ultra-low-power devices, used in power grid and smart grid networks. The algorithm uses elliptic curves over the prime field. Our method might be used for key-distribution via public channels without any other equipment or devices.

Keywords: Low-power device, Cryptography, Elliptic curves, Finite field, Prime field, Binary field, Key distribution, Power grid, Diffie-Hellman algorithm