Unformatted text preview: Partners
The five patents in Table 25.3 are held by Public Key Partners (PKP) of Sunnyvale, California, a partnership between RSADSI and Caro-Kahn, Inc.—the parent company of Cylink. (RSADSI gets 65 percent of the profits and Caro-Kahn gets 35 percent.) PKP claims that these patents, and 4,218,582 in particular, apply to all uses of public-key cryptography. In , PKP wrote: These patents [4,200,770, 4,218,582, 4,405,829, and 4,424,414] cover all known methods of practicing the art of Public Key, including the variations collectively known as ElGamal. Due to the broad acceptance of RSA digital signatures throughout the international community, Public Key Partners strongly endorses its incorporation in a digital signature standard. We assure all interested parties that Public Key Partners will comply with all of the policies of ANSI and the IEEE concerning the availability of licenses to practice this art. Specifically, in support of any RSA signature standard which may be adopted, Public Key Partners hereby gives its assurance that licenses to practice RSA signatures will be available under reasonable terms and conditions on a nondiscriminatory basis. Whether this is true depends on who you talk to. PKP’s licenses have mostly been secret, so there is no way to check if the licenses are standard. Although they claim to have never denied a license to anyone, at least two companies claim to have been denied a license. PKP guards its patents closely, threatening anyone who tries to use public-key cryptography without a license. In part, this is a reaction to U.S. patent law. If you hold a patent and fail to prosecute an infringement, you can lose your patent. There has been much talk about whether the patents are legal, but so far it has all been talk. All legal challenges to PKP’s patents have been settled before judgment. Table 25.3 Public Key Partners’ Patents Patent # Date Inventors Hellman, Diffie, Merkle Patent Covers 4,200,770 4/29/80 4,218,582 8/19/80 4,405,829 9/20/83 4,424,414 3/3/84 4,995,082 2/19/91 Diffie-Hellman Key Exch...
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- Fall '10
- Cryptography, Bruce Schneier, Applied Cryptography, EarthWeb, Search Search Tips