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Crypto Patent Abstracts #1
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
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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.
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