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RSA & Schnorr stifle cryptography-based e-commerce

After widespread use of cryptography had been impeded for years by patents like that on RSA, finally an alternative was found that seemed to be available for free use by the public. But just at that moment, Professor Schnorr from Germany asserted that this free cryptography scheme infringed on his recently obtained crypto patent. The licensing rights of RSA and the Schnorr patent were later exclusively acquired by PKP. PKP harrassed crypto programmers by claiming that "These patents cover all known methods of practicing the art of Public Key, including the variations collectively known as El Gamal".

name	US patent number
Diffie-Hellman	4,200,770
Hellman-Merkle	4,218,582
RSA	4,405,829
Hellman-Pohlig	4,424,414
Schnorr	4,995,082

cyberlaw-rsa

CyberLaw Presents: The RSA Algorithm & The RSA Patent: Patent lawyers analyse the weaknesses of the RSA patent. On the one hand side, it can be attacked as non-statutory, because the only way it goes beyond a pure algorithm is by claiming standard computer implementations of this algorithm, which is, at least according to the law, not permissible. On the other hand side, the RSA algorithm is very similar to a previously known formula. The authors find that the patent has done disproportionate harm, partially because its strength was over-estimated.
(The Crypto Patent Challenge : Collection of Schnorr and PKP related court action documents by Greg Aharonian)
(Public Key Patent Cases -- Roger Shlafly on his successful defense against infringement charges by RSADSI)
(RMS on crypto patent questions)
(Prof. Dr. C.P. Schnorr's Generic Home Page)
Google Search for Schnorr Patent