Elliptic Curve Digital Signatures and Accessories

Digital signatures have been used in Internet applications to provide data authentication and non-repudiation services. Digital signatures will keep on playing an important role in future Internet applications. There are two most well-known public-key cryptosystems, the RSA scheme and the ElGamal scheme, which can provide both digital signature and data encryption. More recently, the Elliptic Curve Cryptosystem (ECC), in which the difficulty of breaking the system is based on the difficulty of computing a discrete logarithm over an elliptic curve, has also been considered to become a standard in the IEEE P1363 project. The ECC shares many similar features with the ElGamal cryptographic system. In this paper, we want to show that, (a) there are variants of elliptic curve digital signatures, and (b) in addition to provide non-repudiation services, there are several interesting accessories associated with discrete-logarithm based digital signatures. These accessories have important features, such as providing subliminal channels, providing multisignatures, and providing batch verification, etc. In better understanding of these features, we can select digital signature schemes with additional features.