I know various applications of RSA signatures. I wonder, is there any real-world applications of ElGamal signatures and encryption?
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1$\begingroup$ Anything unclear with Wikipedia's "The ElGamal signature algorithm (..) is rarely used in practice. A variant developed at NSA and known as the Digital Signature Algorithm is much more widely used" ? Hint: ECDSA is widely used. $\endgroup$– fgrieu ♦Commented Sep 28, 2015 at 11:59
1 Answer
I wonder, is there any real-world applications of ElGamal signatures and encryption?
Rarely.
ElGamal encryption is used very rarely, with GPG being nearly the only common tool, not library, to historically support ElGamal due to patent restrictions with RSA. Other than that it sees little use due to RSA being better promoted, supported and standardized. One could argue that ECIES is basically ElGamal as key encapsulation mechanism, but it's rather derived from ECDH than from ElGamal.
Original ElGamal signatures are even rarer, due to (EC)DSA being better supported and standardized and I actually don't know of any implementation of the original signature scheme. On the other hand on may argue that (EC)DSA is just ElGamal signatures with the signing equation replaced - which is true and acknowledged in the literature (reference: The Handbook of Applied Cryptography (PDF)).
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$\begingroup$ GPG nowadays also promotes RSA for larger key sizes. $\endgroup$– Maarten Bodewes ♦Commented May 16, 2016 at 1:30