Multi-resolution elliptic curve digital signature

Broadcast authentication mechanisms are essential to cyber-physical systems that communicate through wireless links such as wireless sensor networks (WSN) and body area network (BAN). Even though symmetric key-based authentication schemes are more prevalent among these systems, public key-based digital signature schemes have started to gain ground; notably, several research efforts have been focused on the Elliptic Curve Cryptosystem due to its low overheads. As a combination of sensing and computing platform, WSN must handle both time-sensitive as well as delay-tolerant but security-sensitive data. The cryptographic strength and verification delay of an elliptic curve digital signature are determined by the parameters of the curve´s underlying finite held. The held´s parameters and public key are usually generated and distributed before the WSN´s deployment thus cannot be changed easily. This situation creates a need for a multi-resolution digital signature scheme that provides the signer a choice to trade off a signature´s strength for faster verification time and less power consumption. In this paper, we present a digital signature scheme called Multi-Resolution Elliptic Curve Signature (MRECS) that allows the signer the ability to create signatures of different strengths from the same public key set. Compared to an implementation using a set of different keys, MRECS requires less storage overhead and has longer key lifetime at the cost of slightly higher but acceptable communication overhead. MRECS yields up to 33% computational overhead reduction compared to that of the full-size signature while maintaining a full elliptic curve strength regardless of a signature strength.