Unformatted text preview: ange Hellman, Merkle Merkle-Hellman Knapsacks Rivest, Shamir, Adleman RSA Hellman, Pohlig Pohlig-Hellman Schnorr Schnorr Signatures I am not going to dispense legal advice in this book. Maybe the RSA patent will not hold up in court. Maybe the patents do not apply to the entirety of public-key cryptography. (Honestly, I can’t see how they cover ElGamal or elliptic curve cryptosystems.) Perhaps someone will eventually win a suit against PKP or RSADSI. But keep in mind that corporations with large legal departments like IBM, Microsoft, Lotus, Apple, Novell, Digital, National Semiconductor, AT&T, and Sun have all licensed RSA for use in their products rather than fight them in court. And Boeing, Shell Oil, DuPont, Raytheon, and Citicorp have all licensed RSA for their own internal use. In one case, PKP brought suit against TRW Corporation for using the ElGamal algorithm without a license. TRW claimed they did not need a license. PKP and TRW reached a settlement in June 1992. The details of the settlement are unknown, but they included an agreement by TRW to license the patents. This does not bode well. TRW can afford good lawyers; I can only assume that if they thought they could win the suit without spending an unreasonable amount of money, they would have fought. Meanwhile, PKP is having its own internal problems. In June 1994 Caro-Kahn sued RSADSI alleging, among other things, that the RSA patent is invalid and unenforceable . Both partners are trying to have the partnership dissolved. Are the patents valid or not? Will users have to get a license from Caro-Kahn to use the RSA algorithm? Who will own the Schnorr patent? The matter will probably be sorted out by the time this book sees publication. Patents are good for only 17 years, and cannot be renewed. On April 29, 1997, Diffie-Hellman key exchange (and the ElGamal algorithm) will enter the public domain. On September 20, 2000, RSA will enter the public domain. Mark your calendars. 25.6 International Association for...
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