Patents by Inventor Ronald L. Rivest

Ronald L. Rivest 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).

  • Publication number: 20040223481
    Abstract: Techniques are disclosed for providing enhanced privacy in an RFID system comprising a plurality of RFID devices, each having an associated identifier, and at least one reader which communicates with one or more of the devices. A blocker device is operative to receive a communication directed from the reader to one or more of the RFID devices, and to generate, possibly based on information in the received communication, an output transmittable to the reader. The output simulates one or more responses from at least one of the RFID devices in a manner which prevents the reader from determining at least a portion of the identifier of at least one of the RFID devices. The blocker device may itself comprise one of the RFID devices. In an illustrative embodiment, the output generated by the blocker device interferes with the normal operation of a singulation algorithm implemented by the reader.
    Type: Application
    Filed: September 29, 2003
    Publication date: November 11, 2004
    Inventors: Ari Juels, Ronald L. Rivest, Michael Szydlo
  • Publication number: 20040199475
    Abstract: A micropayment system and method is presented for a payor U to establish payment to payee M for a transaction T, which typically has a very low value Tv. The micropayment scheme minimizes the bank's processing costs, while at the same time climinating the need for users and merchants to interact in order to determine whether a given micropayment should be selected for payment. In one embodiment, the micropayment scheme includes time constraints, which require that an electronic check C for the transaction T be presented to a bank B for payment within a predetermined time/date interval. In another embodiment, the micropayment scheme includes a selective deposit protocol, which guarantees that a user is never charged in excess of what he actually spends, even within a probabilistic framework. In another embodiment, the micropayment scheme includes a deferred selection protocol, which provides the bank with control and flexibility over the payment selection process.
    Type: Application
    Filed: June 1, 2004
    Publication date: October 7, 2004
    Inventors: Ronald L. Rivest, Silvio Micali
  • Publication number: 20030105964
    Abstract: A time-based method for generating an authentication code associated with an entity uses an authentication code generated from a secret, a dynamic, time-varying variable, and the number of previous authentication code generations within the particular time interval. Other information such as a personal identification number (PIN) and a verifier identifier can also be combined into the authentication code.
    Type: Application
    Filed: December 4, 2001
    Publication date: June 5, 2003
    Inventors: John G. Brainard, Burton S. Kaliski, Ronald L. Rivest
  • Publication number: 20020025035
    Abstract: A plaintext message to be encrypted is segmented into a number of words, e.g., four words stored in registers A, B, C and D, and an integer multiplication function is applied to a subset of the words, e.g., to the two words in registers B and D. The use of such an integer multiplication greatly increases the diffusion achieved per round of encryption, allowing for higher security per round, and increased throughput. The integer multiplication function may be a quadratic function of the form ƒ(x)=x(ax+b), where a is an even integer and b is an odd integer, or other suitable function such as a higher-order polynomial. The results of the integer multiplication function are rotated by 1 g w bits, where 1 g denotes log base 2 and w is the number of bits in a given word, to generate a pair of intermediate results t and u. An exclusive-or of another word, e.g., the word in register A, and one of the intermediate results, e.g., t, is rotated by an amount determined by the other intermediate result u.
    Type: Application
    Filed: June 8, 2001
    Publication date: February 28, 2002
    Inventors: Ronald L. Rivest, Matthew John Barton Robshaw, Raymond Mark Sidney, Yiqun Lisa Yin
  • Patent number: 6269163
    Abstract: A plaintext message to be encrypted is segmented into a number of words, e.g., four words stored in registers A, B, C and D, and an integer multiplication function is applied to a subset of the words, e.g., to the two words in registers B and D. The integer multiplication function may be a quadratic function of the form ƒ(x)=x(ax+b) or other suitable function such as a higher-order polynomial. The results of the integer multiplication function are rotated by lg w bits, where lg denotes log base 2 and w is the number of bits in a given word, to generate a pair of intermediate results t and u. An exclusive-or of another word, e.g., the word in register A, and one of the intermediate results, e.g., t, is rotated by an amount determined by the other intermediate result u. Similarly, an exclusive-or of the remaining word in register D and the intermediate result u is rotated by an amount determined by the other intermediate result t.
    Type: Grant
    Filed: June 15, 1998
    Date of Patent: July 31, 2001
    Assignee: RSA Security Inc.
    Inventors: Ronald L. Rivest, Matthew John Barton Robshaw, Raymond Mark Sidney, Yiqun Lisa Yin
  • Patent number: 5835600
    Abstract: A simple encryption and decryption device has been developed. The underlying algorithm is a fast block cipher that may be implemented efficiently in hardware or software. The algorithm makes heavy use of data-dependent rotations. The amount of each rotation depends on the data being encrypted and intermediate encryption results. The variables for the algorithm include word size, rounds, and the length of a secret key.
    Type: Grant
    Filed: April 21, 1997
    Date of Patent: November 10, 1998
    Assignee: RSA Data Security, Inc.
    Inventor: Ronald L. Rivest
  • Patent number: 5724428
    Abstract: A simple encryption and decryption device has been developed. The underlying algorithm is a fast block cipher that may be implemented efficiently in hardware or software. The algorithm makes heavy use of data-dependent rotations. The amount of each rotation depends on the data being encrypted and intermediate encryption results. The variables for the algorithm include word size, rounds, and the length of a secret key.
    Type: Grant
    Filed: November 1, 1995
    Date of Patent: March 3, 1998
    Assignee: RSA Data Security, Inc.
    Inventor: Ronald L. Rivest
  • Patent number: 5144667
    Abstract: Access to a vehicle by a remote electronic key via a radio link is secured by an exchange of encrypted signals. A remote unit having a secret number is introduced to a base unit and a common key is agreed upon by an exponential key exchange. The common key is encrypted using the secret number and stored in the base unit. Thereafter, the base unit is able to authenticate the identity of the remote unit by sending the encrypted common key and a random number to the remote unit which decrypts the key and uses it to encrypt the random number. The random number is also encrypted in the base unit and compared with the encrypted random number from the remote unit.
    Type: Grant
    Filed: December 20, 1990
    Date of Patent: September 1, 1992
    Assignee: Delco Electronics Corporation
    Inventors: Russell W. Pogue, Jr., Ronald L. Rivest
  • Patent number: 4691299
    Abstract: Storage media such as digital optical disks, PROMS, and paper tape consist of a number of bit positions which initially contain a "zero" and which can later be irreversibly overwritten with a "one". An apparatus and method provide for rewriting in such "non-erasable memories" for expanding their capacity by allowing the non-erasable memory to be rewritten one or more time.
    Type: Grant
    Filed: December 29, 1983
    Date of Patent: September 1, 1987
    Assignee: Massachusetts Institute of Technology
    Inventors: Ronald L. Rivest, Adi Shamir
  • Patent number: 4405829
    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.
    Type: Grant
    Filed: December 14, 1977
    Date of Patent: September 20, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: Ronald L. Rivest, Adi Shamir, Leonard M. Adleman
  • Patent number: 4376299
    Abstract: A data center for remote postage meter recharging receives resetting signal information to reset a remotely located postage meter. The remotely located postage meter has signal information stored therein for use in recharging the meter with additional postage in conjunction with a signal information received from the data center and entered into the meter. The data center includes a sealed unit for processing received resetting signal information and encrypted signal information stored at the data center outside of the sealed unit. The stored encrypted signal information at the data center is equivalent to the signal information stored in the remotely located postage meter. The sealed unit includes a decrypter for decrypting the encrypted signal information so that it may be combined with the resetting signal information to generate a signal for use in resetting the remotely located postage meter.
    Type: Grant
    Filed: July 14, 1980
    Date of Patent: March 8, 1983
    Assignee: Pitney Bowes, Inc.
    Inventor: Ronald L. Rivest