Cypherpunks, I finally got to the library to do some patent searches. Attached to this mail is summary information on 6 significant crypto patents. Note that some of the patent numbers which have appeared in prior postings on cypherpunks were incorrect, but I managed to track down the references via other means; someone should make sure they're correct in any relavent FAQs etc. Of the 6, I have full-text for 4 of them: Schnorr: 4,995,082 Gaffney: 4,562,305 Hellman-Pohlig: 4,424,414 Rivest-Shamir: 4,405,829 and partial text for one more: Hellman-Merkle: 4,218,582 I hope to be able to get a full version of Hellman-Merkle, as well as: Hellman-Diffie: 4,200,770 within a week. So, is there an FTP site I should place these on? Have fun, J.J. Larrea O / \/ /\ ~~~~~~~~~~~~~~~~~~~~~~~~~~~ CUT HERE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ O \ US PAT NO: 4,995,082 [IMAGE AVAILABLE] L19: 1 of 5 DATE ISSUED: Feb. 19, 1991 TITLE: Method for identifying subscribers and for generating and verifying electronic signatures in a data exchange system INVENTOR: Claus P. Schnorr, Frankfurterstr. 81, 6350 Bad Nauheim, Federal Republic of Germany APPL-NO: 07/484,127 DATE FILED: Feb. 23, 1990 ART-UNIT: 222 PRIM-EXMR: Thomas H. Tarcza ASST-EXMR: David Cain LEGAL-REP: Hill, Van Santen, Steadman & Simpson ABSTRACT: In a data exchange system working with processor chip cards, a chip card transmits coded identification data I, v and, proceeding from a random, discrete logarithm r, an exponential value x=2.sup.r (mod p) to the subscriber who, in turn, generates and transmits a random bit sequence e to the chip card. By multiplication of a stored, private key s with the bit sequence e and by addition of the random number r, the chip card calculates a y value and transmits the y value to the subscriber who, in turn, calculates an x value from the information y, v.sub.j and e and checks whether the calculated x value coincides with the transmitted x value. For an electronic signature, a hash value e is first calculated from an x value and from the message m to be signed and a y value is subsequently calculated from the information r, s.sub.j and e. The numbers x and y then yield the electronic signature of the message m. US PAT NO: 4,405,829 [IMAGE AVAILABLE] L19: 3 of 5 DATE ISSUED: Sep. 20, 1983 TITLE: Cryptographic communications system and method INVENTOR: Ronald L. Rivest, Belmont, MA Adi Shamir, Cambridge, MA Leonard M. Adleman, Arlington, MA ASSIGNEE: Massachusetts Institute of Technology, Cambridge, MA (U.S. corp.) APPL-NO: 05/860,586 DATE FILED: Dec. 14, 1977 ART-UNIT: 222 PRIM-EXMR: Sal Cangialosi LEGAL-REP: Arthur A. Smith, Jr., Robert J. Horn, Jr. ABSTRACT: A cryptographic communications system and method. The system includes a communications channel coupled to at least one terminal having an encoding device and to at least one terminal having a decoding device. A message-to-be-transferred is enciphered to ciphertext at the encoding terminal by first encoding the message as a number M in a predetermined set, and then raising that number to a first predetermined power (associated with the intended receiver) and finally computing the remainder, or residue, C, when the exponentiated number is divided by the product of two predetermined prime numbers (associated with the intended receiver). The residue C is the ciphertext. The ciphertext is deciphered to the original message at the decoding terminal in a similar manner by raising the ciphertext to a second predetermined power (associated with the intended receiver), and then computing the residue, M', when the exponentiated ciphertext is divided by the product of the two predetermined prime numbers associated with the intended receiver. The residue M' corresponds to the original encoded message M. US PAT NO: 4,200,770 [IMAGE AVAILABLE] L19: 5 of 5 DATE ISSUED: Apr. 29, 1980 TITLE: Cryptographic apparatus and method INVENTOR: Martin E. Hellman, Stanford, CA Bailey W. Diffie, Berkeley, CA Ralph C. Merkle, Palo Alto, CA ASSIGNEE: Stanford University, Palo Alto, CA (U.S. corp.) DATE ISSUED: Apr. 29, 1980 TITLE: Cryptographic apparatus and method APPL-NO: 05/830,754 DATE FILED: Sep. 6, 1977 ART-UNIT: 222 PRIM-EXMR: Howard A. Birmiel LEGAL-REP: Flehr, Hohbach, Test ABSTRACT: A cryptographic system transmits a computationally secure cryptogram over an insecure communication channel without prearrangement of a cipher key. A secure cipher key is generated by the conversers from transformations of exchanged transformed signals. The conversers each possess a secret signal and exchange an initial transformation of the secret signal with the other converser. The received transformation of the other converser's secret signal is again transformed with the receiving converser's secret signal to generate a secure cipher key. The transformations use non-secret operations that are easily performed but extremely difficult to invert. It is infeasible for an eavesdropper to invert the initial transformation to obtain either conversers' secret signal, or duplicate the latter transformation to obtain the secure cipher key. US PAT NO: 4,562,305 [IMAGE AVAILABLE] L22: 1 of 3 DATE ISSUED: Dec. 31, 1985 TITLE: Software cryptographic apparatus and method INVENTOR: John E. Gaffney, Jr., Bethesda, MD ASSIGNEE: International Business Machines Corporation, Armonk, NY (U.S. corp.) APPL-NO: 06/452,248 DATE FILED: Dec. 22, 1982 ART-UNIT: 222 DATE ISSUED: Dec. 31, 1985 TITLE: Software cryptographic apparatus and method PRIM-EXMR: Salvatore Cangialosi ASST-EXMR: Aaron J. Lewis LEGAL-REP: John E. Hoel ABSTRACT: An improved software cryptographic apparatus and method are disclosed. The apparatus and method enables the encryption of the object code of a program so as to enable relocatable code operations. The apparatus and method will adapt program execution for a mixture of encrypted and nonencrypted code. A particular advantage of the apparatus and method is its accommodation of interrupts and branches while carrying out the cryptographic function. US PAT NO: 4,424,414 [IMAGE AVAILABLE] L22: 2 of 3 DATE ISSUED: Jan. 3, 1984 TITLE: Exponentiation cryptographic apparatus and method INVENTOR: Martin E. Hellman, Stanford, CA Stephen C. Pohlig, Acton, MA ASSIGNEE: Board of Trustees of the Leland Stanford Junior University, Stanford, CA (U.S. corp.) APPL-NO: 05/901,770 DATE FILED: May 1, 1978 ART-UNIT: 222 PRIM-EXMR: Sal Cangialosi LEGAL-REP: Flehr, Hohbach, Test, Albritton & Herbert ABSTRACT: A cryptographic system transmits a computationally secure cryptogram that is generated from a secret transformation of the message sent by the authorized transmitter; the cryptogram is again transformed by the authorized receiver using a secret reciprocal transformation to reproduce the message sent. The secret transformations use secret cipher keys that are known only by the authorized transmitter and receiver. The transformations are performed with nonsecret operations, exponentiation, that are easily performed but extremely difficult to invert. It is computationally infeasible for an eavesdropper either to solve known plaintext-ciphertext pairs for the secret cipher keys, or to invert the nonsecret operations that are used to generate the cryptogram. US PAT NO: 4,218,582 [IMAGE AVAILABLE] L22: 3 of 3 DATE ISSUED: Aug. 19, 1980 TITLE: Public key cryptographic apparatus and method INVENTOR: Martin E. Hellman, Stanford, CA Ralph C. Merkle, Palo Alto, CA DATE ISSUED: Aug. 19, 1980 TITLE: Public key cryptographic apparatus and method ASSIGNEE: The Board of Trustees of the Leland Stanford Junior University , Stanford, CA (U.S. corp.) APPL-NO: 05/839,939 DATE FILED: Oct. 6, 1977 ART-UNIT: 222 PRIM-EXMR: Howard A. Birmiel ABSTRACT: A cryptographic system transmits a computationally secure cryptogram that is generated from a publicly known transformation of the message sent by the transmitter; the cryptogram is again transformed by the authorized receiver using a secret reciprocal transformation to reproduce the message sent. The authorized receiver's transformation is known only by the authorized receiver and is used to generate the transmitter's transformation that is made publicly known. The publicly known transformation uses operations that are easily performed but extremely difficult to invert. It is infeasible for an unauthorized receiver to invert the publicly known transformation or duplicate the authorized receiver's secret transformation to obtain the message sent. *** END ***