Computer Security and Cryptography

19.10 U.S. PATENT 4,405,829 [RIVERST ET AL., 1977]

The ‘770, ‘582, and ‘829 patents described in Sections 19.8 to 19.10 were to be the motherlode for Public Key Partners (PKP) of Sunnyvale, California, a partnership between RSA Data Security Incorporated (RSADSI), now shorted to RSA and Caro-Kahn, Incorporated, the parent corporation of Cylink. In [Fougner, 1999], PKP's licensing officer claimed that these patents

… cover all known methods of practicing the art of Public Key, including the variations collectively known as El Gamal.

Figure 19.4 '829 patent.

Ultimately, the “partners” had a falling out, primarily because PKP was not able to receive royalties from their licensing of RSADSI products and after all … the Merkle–Hellman knapsack system seemed like an unlikely source of riches.