Patents by Inventor Frank T. Leighton

Frank T. Leighton has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5521591
    Abstract: A class of switching networks is comprised of expansive logical clusters and/or dispersive logical clusters. These clusters are of low degree. The class of networks include multibutterfly networks as well as multi-Benes networks. These networks provide for fault tolerance and routing and for efficient routing. Moreover, routing is provided in a non-blocking fashion.
    Type: Grant
    Filed: March 25, 1994
    Date of Patent: May 28, 1996
    Assignee: Massachusetts Institute of Technology
    Inventors: Sanjeev Arora, Thomas F. Knight, Jr., Frank T. Leighton, Bruce M. Maggs, Eliezer Upfal
  • Patent number: 5519778
    Abstract: The present invention describes a method for enabling users of a cryptosystem to agree on secret keys. In one embodiment, a trusted agent chooses at least one individual key for each user, with at least a portion of such individual key being secret. At least some of the individual keys are then stored in physically secure devices, and the pair of users i and j use their individual keys to compute a common secret key. In another embodiment, each trustee of a group of trustees choose at least one individual key for each user, with at least some portion of such individual key being secret. The keys chosen by a sufficiently small number of such trustees, however, are insufficient for computing the common secret key of the users. Other hardware and software key exchange protocols based on these two techniques are also disclosed.
    Type: Grant
    Filed: September 26, 1994
    Date of Patent: May 21, 1996
    Assignee: Silvio Micali
    Inventors: Frank T. Leighton, Silvio Micali
  • Patent number: 5432852
    Abstract: The present invention describes new digital signature schemes that are provably secure against any adaptive chosen-message attack. The scheme, which is based on selection of a hash function from a space of such functions, has a very short public key, fast signing, a reasonable signature length and high security. Several algorithmic techniques are provided for enhancing the efficiency of the signature scheme in terms of time and memory.
    Type: Grant
    Filed: September 29, 1993
    Date of Patent: July 11, 1995
    Inventors: Frank T. Leighton, Silvio Micali
  • Patent number: 5351302
    Abstract: The method and system of the present invention utilizes public-key cryptography to create "secure" titles for personal and real property such as vehicles and the like. The title preferably comprises a card in which is stored a digital signature of one or more identifiers such as a vehicle identification number, the vehicle license plate and the owner's name. To effect a transfer of the property, the digital signature on the title must first be shown to have been generated from the one or more identifiers.
    Type: Grant
    Filed: May 26, 1993
    Date of Patent: September 27, 1994
    Inventors: Frank T. Leighton, Silvio Micali
  • Patent number: 4995081
    Abstract: The method and system for the invention utilizes any of a number of "proofs of legitimacy" to generate and verify a personal identification card. A card is generated by computing a digital signature of a non-secret password. The password and the digital signature are then encoded and stored on a magnetic stripe or other memory device of the card. To effect a transaction, the digital signature on a received card must be shown to have been generated from the password on the received card. The password preferably includes a digitized photograph of the authorized cardholder which is capable of being displayed at the transaction terminal. This enables the operator of the terminal to verify the identity of the cardholder by visual inspection.
    Type: Grant
    Filed: November 6, 1989
    Date of Patent: February 19, 1991
    Inventors: Frank T. Leighton, Silvio Micali
  • Patent number: 4879747
    Abstract: The method and system of the invention utilizes a private key of a public-key cryptosystem key pair to encrypt a non-secret password into a digital signature. The password and the digital signature are then encoded and stored on a magnetic stripe or other memory device of the card. To effect a transaction, the digital signature on a received card must be shown to have been generated from the password on the received card. The password preferably includes a digitized photograph of the authorized cardholder which is capable of being displayed at the transaction terminal. This enables the operator of the terminal to verify the identity of the cardholder by visual inspection.
    Type: Grant
    Filed: March 21, 1988
    Date of Patent: November 7, 1989
    Inventors: Frank T. Leighton, Silvio Micali