Es de recalcar que aunque el algoritmo citado puede
emplearse también para cifrar información, su complejidad y el hecho de
duplicar el texto cifrado la longitud del texto en claro lo hacen poco
recomendable para tal fin. [Ribagorda:1997]
Algoritmo criptográfico de clave pública que puede
emplearse tanto para cifrar como para obtener firmas digitales y que basa su
seguridad en la dificultad de calcular logaritmos discretos en un campo finito.
[CESID:1997]
(N) An algorithm for
asymmetric cryptography, invented in 1985 by Taher El Gamal, that is based on
the difficulty of calculating discrete logarithms and can be used for both
encryption and digital signatures. [ElGa] [RFC4949:2007]
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 1984 (see T. ElGamal,
A public key cryptosystem and a signature scheme based on discrete logarithms,
IEEE Trans inf Theo, 31:469-472, 1985).
The ElGamal signature
algorithm described in this article is rarely used in practice. A variant
developed at NSA and known as the Digital Signature Algorithm is much more
widely used. There are several other variants (see K. Nyberg and R. A. Rueppel,
Message recovery for signature schemes based on the discrete logarithm problem,
J Crypt, 8:27-37, 1995). The ElGamal signature scheme must not be confused with
ElGamal encryption which was also invented by Taher ElGamal.
The ElGamal signature scheme
allows that a verifier can confirm the authenticity of a message m sent by the
signer sent to him over an insecure channel.
http://en.wikipedia.org/wiki/ElGamal_signature_scheme