ElGamal Encryption with the RFC 9500 Test Key Set

One of the highlights of my academic career has been talking with the mighty Tahir ElGamal, and who created the ElGamal encryption method. In this page, I will outline how ElGamal encryption works and outline a new set of test vectors within RFC 9500 [here].

Taher is one of the giants of cybersecurity, and his work on Netscape led to the creation of SSL. Along with this, he published this paper in 1985 [here]:

It was true classic and has been since been referenced over 12,500 times. Within the paper, Tahir outlined encryption and digital signature methods. His ‘base’ was to take John Napier’s logarithms and make them discrete. This discrete element meant that we only dealt with positive integer values and where we worked within a finite field. This field was defined by a prime number (p).

While the core ElGamal encryption method was overtaken in its usage by RSA, and then by ECC (Elliptic Curve Cryptography), the signature method was adopted as the Digital Signature Standard (DSS) by NIST. This has since scaled into ECC to become ECDSA, and which is used by Bitcoin and Ethereum.