The ElGamal signature scheme is a digital signature scheme which is based on the difficulty of computing discrete logarithms. It was described by Taher Elgamal in 1985.[1]
The ElGamal signature algorithm is rarely used in practice. A variant developed at the NSA and known as the Digital Signature Algorithm is much more widely used. There are several other variants.[2] The ElGamal signature scheme must not be confused with ElGamal encryption which was also invented by Taher Elgamal.