oz@nexus.YorkU.CA (Ozan Yigit) (05/17/91)
[The following article is from sci.crypt, and it is re-posted in these newsgroups for your information. The author had earlier announced rpem, a Privacy Enhanced Mail/public-key program. RSA thinks this code infringes on their patents.] >From: riordanmr@clvax1.cl.msu.edu (Mark Riordan) Newsgroups: sci.crypt Subject: rpem: RSA patent questions Keywords: RSA patent rpem Message-ID: <1991May16.201709.3086@msuinfo.cl.msu.edu> Date: 16 May 91 20:17:09 GMT Article-I.D.: msuinfo.1991May16.201709.3086 Posted: Thu May 16 16:17:09 1991 Sender: news@msuinfo.cl.msu.edu Organization: Michigan State University Lines: 115 I hate to bring up the old RSA software patent question again, but this time we have a real life situation. As you can see from the message below, RSA is unhappy with my releasing a public key encryption program. I claim that the algorithm here does not closely resemble RSA and therefore should not infringe upon the patent(s). They claim otherwise. I seek advice, or pointers to advice, in this real-life situation. ---------------------------------------------------------------------------- Incidentally, here is a quick sketch of "their" technique versus "mine": Both systems start with two primes, p and q. ----- RSA requires the user to select an arbitrary encryption key, e. From e, p, and q is computed the corresponding decryption key, d. Encryption and decryption are almost identical: ciphertext = plaintext^e mod pq plaintext = ciphertext^d mod pq ----- The system I use (which I call "Rabin" but which may not be the same as what most people call "Rabin"; I've never located the original paper) works like this: ciphertext = plaintext^2 mod pq Decryption is more difficult. The square roots of the ciphertext mod p and mod q are computed using Berlekamp's square root algorithm. (It's magic to me, and works only for prime moduli. If Berlekamp worked for composite moduli, the whole cipher would be worthless.) Then the Chinese Remainder Theorem is used on the these two square roots mod p and q to find the 4 square roots of the ciphertext mod pq. One of these square roots is the plaintext; the correct one is selected based on redundant information added in during the encryption process. ----------------------------------------------------------------- I'm not exactly putting my decision up to a vote on sci.crypt (what a ghastly thought that would be), but what do you folks think I should do? Email directly to me if you think that the net has suffered through patent discussions enough already. Mark Riordan riordanmr@clvax1.cl.msu.edu ===== Received mail follows ============================================ >From: jim@RSA.COM (Jim Bidzos) Message-Id: <9105161715.AA06925@RSA.COM> To: "Mark Riordan" <riordanmr@clvax1.cl.msu.edu> Cc: "pem-dev" <pem-dev@TIS.COM> Subject: Re: rpem: Simple Privacy Enhanced Mail system In-Reply-To: "Mark Riordan"'s message of 16 May 91 10:29:00 EDT <9105161431.AA07051@TIS.COM> Sender: pem-dev-relay@TIS.COM The author of the following message does not have direct Internet access. Paper mail will follow to Mark Riordan and Michigan State University. ---------------------------------------------------------------------- May 16, 1991 Dear Mr. Riordan, We refer to your posting to pem-dev@tis.com of May 16, 1991: > Announcing the initial release of "rpem", a mostly public domain > Privacy Enhanced Mail program incorporating a public key encryption system > The public key encryption algorithm used in rpem is Rabin's: > ciphertext = plaintext^2 mod pq (p, q are primes) > The public component of the key is pq, and the private component > is p and q. Rabin's algorithm is probably slower (on decryption) and less > aesthetically pleasing than RSA, for instance, but it's in the > public domain. Also, unlike RSA, breaking Rabin's scheme is provably > as hard as factoring a product of two primes. The Massachusetts Institute of Technology and the Board of Trustees of the Leland Stanford Junior University have granted Public Key Partners exclusive sublicensing rights to the following patents registered in the United States, and all of their corresponding foreign patents: Cryptographic Apparatus and Method ("Diffie-Hellman") .......................... No. 4,200,770 Public Key Cryptographic Apparatus and Method ("Hellman-Merkle") ............... No. 4,218,582 Cryptographic Communications System and Method ("RSA") .............................. No. 4,405,829 Exponential Cryptographic Apparatus and Method ("Hellman-Pohlig") ............... No. 4,424,414 These patents cover most known methods of practicing the art of public-key cryptography, including the system commonly known as "Rabin," which is NOT, contrary to your claim, public domain, and is covered by at least two of the patents listed above. WE HEREBY PLACE YOU AND ALL USERS OF YOUR IMPLEMENTATION OF PUBLIC KEY, ON NOTICE THAT THEY ARE INFRINGING ON THESE PATENTS AND WE RESERVE ALL OF OUR RIGHTS AND REMEDIES AT LAW. Yours, Public Key Partners Robert B. Fougner, Esq. Director of Licensing Jim Bidzos adds: One of the patents we cited has broad claims on cryptosystems based on exponentiation. This would cover a cryptosystem that used CR theorem, since it does tow (or more) exp's with a combining operation. The traditional Rabin method, we believe, is clearly covered by the RSA patent itself as the claims allude to non-odd e and/or d.
hollaar%basset.utah.edu@cs.utah.edu (Lee Hollaar) (05/18/91)
>I hate to bring up the old RSA software patent question again, but >this time we have a real life situation. >As you can see from the message below, RSA is unhappy with my releasing >a public key encryption program. >I claim that the algorithm here does not closely resemble RSA and >therefore should not infringe upon the patent(s). They claim otherwise. To know whether something infringes a patent, you have to read the claims in the patent. The claims can be much broader than the invention that the patent is to protect. This is particularly true for pioneering inventions. When reading the claims, you see if each element of the invention recited in the claim is present in your invention. If all elements are present, then you infringe the patent. If just one element of the claim is not present, then there is no infringement. If your invention contains things not present in the patent claim, and the claim describes the invention as "comprising" the elements, then you still infringe. If you have an element that is similar to, but not exactly like, one in the claim, you may still be infringing under the "doctrine of equivalence." The penalties for infringement can be stiff, and they are even worse for intentional infringement (which would probably be the case here because of the warning letter). The Court of Appeals for the Federal Circuit, which handles all patent infringement appeals, has made it almost impossible to be an innocent infringer of a valid patent that you know exists. And it's not just the person who distributes the program, but anybody who makes, uses, or sells the patented invention within the United States. Don't depend on information from people on the net who might not understand patent law. See a good patent attorney or patent agent. Lee Hollaar Professor of Computer Science Registered Patent Agent
a_rubin@dsg4.dse.beckman.com (05/21/91)
In <1991May17.144807.29903@hellgate.utah.edu> hollaar%basset.utah.edu@cs.utah.edu (Lee Hollaar) writes: >To know whether something infringes a patent, you have to read the claims >in the patent. The claims can be much broader than the invention that the >patent is to protect. This is particularly true for pioneering inventions. >When reading the claims, you see if each element of the invention recited >in the claim is present in your invention. If all elements are present, >then you infringe the patent. If just one element of the claim is not >present, then there is no infringement. If your invention contains things >not present in the patent claim, and the claim describes the invention as >"comprising" the elements, then you still infringe. If you have an element >that is similar to, but not exactly like, one in the claim, you may still >be infringing under the "doctrine of equivalence." My understanding is that, if the any element of the claim is "prior art", then that claim is invalid, (but you have to go to court to prove it). >The penalties for infringement can be stiff, and they are even worse for >intentional infringement (which would probably be the case here because of >the warning letter). The Court of Appeals for the Federal Circuit, which >handles all patent infringement appeals, has made it almost impossible to >be an innocent infringer of a valid patent that you know exists. And it's >not just the person who distributes the program, but anybody who makes, uses, >or sells the patented invention within the United States. Another message in a related thread stated (quoting actual patent law) that only using or selling is an infringement -- making a patented invention is not infringement. >Don't depend on information from people on the net who might not understand >patent law. See a good patent attorney or patent agent. Agreed. -- a_rubin@dsg4.dse.beckman.com My opinions are my own, and do not represent those of my employer.
brnstnd@kramden.acf.nyu.edu (Dan Bernstein) (05/22/91)
In article <a_rubin.674776385@dn71> a_rubin@dsg4.dse.beckman.com writes: > Another message in a related thread stated (quoting actual patent law) > that only using or selling is an infringement -- making a patented > invention is not infringement. This is not correct. If someone invents the bottomless soap dish and patents it, then anyone who makes, uses, or sells bottomless soap dishes is liable for infringement. On the other hand, if someone invents a new way of curing rubber and patents it, then there's no way to infringe the invention by making or selling it. You can make rubber, and you can make cured rubber, but how do you make the *process* of curing rubber? That doesn't make sense. The only way to infringe a method patent is to use the method. ---Dan
hanche@imf.unit.no (Harald Hanche-Olsen) (05/23/91)
In article <19060:May2120:58:0591@kramden.acf.nyu.edu> brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes: In article <a_rubin.674776385@dn71> a_rubin@dsg4.dse.beckman.com writes: > Another message in a related thread stated (quoting actual patent law) > that only using or selling is an infringement -- making a patented > invention is not infringement. This is not correct. If someone invents the bottomless soap dish and patents it, then anyone who makes, uses, or sells bottomless soap dishes is liable for infringement. I have seen many references to this "makes, uses, or sells" notion of the patent law, and it still has me somewhat confused. Is there no definition of what is meant by "making" and "using", or maybe exceptions stated in the law? The reason I am asking is this: I had always thought it is ok to "make and use" a patented invention for the purpose of exploring the patent and its applications. Thus, if my understanding is correct, we could all implement RSA, and we could have a friendly competition over who makes the most efficient implementation and so on, as long as we do not USE the system in the sense of storing and/or transmitting encrypted data. If we do the latter, we infringe. But by just exploring the possibilities, we do not. Have I got it wrong? If I do, I have another question. If a professor gives a lecture in which she fires up Maple and steps through the encryption/decryption parts of RSA as a demonstration, does she then infringe?? Where is the limit to what you can do? Just asking because I am confused - RSA isn't patented in my parts of the world, so this doesn't really concern me directly... - Harald Hanche-Olsen <hanche@imf.unit.no> Division of Mathematical Sciences The Norwegian Institute of Technology N-7034 Trondheim, NORWAY
brnstnd@kramden.acf.nyu.edu (Dan Bernstein) (05/23/91)
In article <HANCHE.91May22203428@hufsa.imf.unit.no> hanche@imf.unit.no (Harald Hanche-Olsen) writes: > I have seen many references to this "makes, uses, or sells" notion of > the patent law, and it still has me somewhat confused. Is there no > definition of what is meant by "making" and "using", or maybe > exceptions stated in the law? Courts don't bother defining the English language. They only clarify what they meant at the fine lines. Sure, there are exceptions everywhere, but they don't change what ``making'' means. > The reason I am asking is this: I had > always thought it is ok to "make and use" a patented invention for the > purpose of exploring the patent and its applications. The precise legal phrase is this: ``for the sole purpose of satisfying philosophical taste or curiosity, or for instruction and amusement.'' Such use never infringes a patent. This wording has been repeated in several court cases and forms a very strong precedent by now. > Have I got it wrong? You've got it right. ---Dan
diamond@jit533.swstokyo.dec.com (Norman Diamond) (05/23/91)
In article <4547:May2223:16:3391@kramden.acf.nyu.edu> brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes: >In article <HANCHE.91May22203428@hufsa.imf.unit.no> hanche@imf.unit.no (Harald Hanche-Olsen) writes: >> The reason I am asking is this: I had >> always thought it is ok to "make and use" a patented invention for the >> purpose of exploring the patent and its applications. > >The precise legal phrase is this: ``for the sole purpose of satisfying >philosophical taste or curiosity, or for instruction and amusement.'' -------------------------------- Does this mean that if I make one for instruction without amusement, it is illegal? So if I make a copy of a patented graphical game (which does not amuse me) to see how it works, then it is illegal, but if I make a copy of a patented text adventure (which does amuse me) to see how it works, then it's legal? This is a serious question. The reason I ask it is, of course, that practical use might turn it on its head. If instruction by itself is sufficient (that is, if they really meant "for instruction OR amusement"), then amusement by itself is sufficient. However, in order to get a reliable answer, I had to ask the preceding question. -- Norman Diamond diamond@tkov50.enet.dec.com If this were the company's opinion, I wouldn't be allowed to post it. Permission is granted to feel this signature, but not to look at it.
aipdc@castle.ed.ac.uk (Paul Crowley) (05/23/91)
In article <4547:May2223:16:3391@kramden.acf.nyu.edu> brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes: >The precise legal phrase is this: ``for the sole purpose of satisfying >philosophical taste or curiosity, or for instruction and amusement.'' >Such use never infringes a patent. I have no use whatsoever for cryptographic technology or software, I'm just a curious amateur. Anyone out there want to send me an implementation of the RSA cypher? ____ \/ o\ Paul Crowley aipdc@castle.ed.ac.uk \ / /\__/ Part straight. Part gay. All queer. \/ PS: as far as I know, since I'm in the UK, this law doesn't apply to be anyway.
perl@dwrsun2.UUCP (Robert Perlberg) (06/15/91)
In article <4547:May2223:16:3391@kramden.acf.nyu.edu>, brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes: > The precise legal phrase is this: ``for the sole purpose of satisfying > philosophical taste or curiosity, or for instruction and amusement.'' ^^^^^^^^^^^^^^^^^^^ What does "philosophical taste" mean? > philosophical taste or curiosity, or for instruction and amusement.'' ^^^^^^^^^ Suppose the intended purpose of the invention *is* amusement. Can I make and use a patented video game? Come to think of it, what is the legal status of work-alike games posted to comp.sources, such as Tetris and PacMan? Robert Perlberg Dean Witter Reynolds Inc., New York murphy!dwrsun2!perl -- "I am not a language ... I am a free man!"