Stephen Pohlig
Stephen Pohlig was an electrical engineer who worked in the MIT Lincoln Laboratory. As a graduate student of Martin Hellman's at Stanford University in the mid-1970s, he helped develop the underlying concepts of Diffie-Hellman key exchange, including the Pohlig–Hellman exponentiation cipher and the Pohlig–Hellman algorithm for computing discrete logarithms. That cipher can be regarded as a predecessor to the RSA since all that is needed to transform it into RSA is to change the arithmetic from modulo a prime number to modulo a composite number.
In his spare time Stephen Pohlig was a keen kayaker known to many throughout the New England area.