Dr. Taher Elgamal (Arabic: طاهر الجمل ) (Born 18 August 1955) (sometimes seen El Gamal and ElGamal, but Elgamal is preferred, see below) is an American-Egyptian cryptographer. In 1985, Elgamal published a paper titled A Public key Cryptosystem and A Signature Scheme based on discrete Logarithms in which he proposed the design of the ElGamal discrete log cryptosystem. This scheme became the basis for Digital Signature Algorithm (DSA) adopted by National Institute of Standards and Technology (NIST) as the Digital Signature Standard (DSS). He also participated in the 'SET' credit card payment protocol, plus a number of Internet payment schemes.

Elgamal has had Bachelor of Science degree from Cairo University, and Masters and Doctorate degrees in Computer Science from Stanford University. He served as chief scientist at Netscape Communications from 1995 to 1998 where he was a driving force behind SSL. He also was the director of engineering at RSA Security Inc. before founding Securify in 1998 and becoming their CEO. When Securify was acquired by Kroll-O'Gara he became the president of its information security group. Presently (2004), Securify is again independent and Elgamal is Chief Technical Officer & Co-Chair of the Board of Directors. In addition, Elgamal sits on the board of FaceTime Communications [1], a company which provides security solutions for instant messaging and peer-to-peer applications.

Dr. Elgamal's surname has been spelled as two words (the El part is equalivant to "the" in English), and as a single word with an intra-capital. The cryptographic literature is full of both spellings. Dr Elgamal himself spells it as a singly-capitalized surname, as this is less likely to be mangled in English.