Patents Examined by Tod Swann
  • Patent number: 6215876
    Abstract: An apparatus and method for detecting erroneous initialization vectors transmitted over a communications channel and maintaining cryptographic synchronization by comparing a received vector with a predicted correct vector. The vectors are random-like in nature by utilizing a pseudo-random number generator having a long overall cycle length. If the level of bit errors of the comparison is relatively small, considering the predicted vector is considered correct and used for synchronization, but if the number of bit errors of the comparison is relatively large, the predicated vector is considered in correct.
    Type: Grant
    Filed: December 31, 1997
    Date of Patent: April 10, 2001
    Assignee: Transcrypt International, Inc.
    Inventor: James E. Gilley
  • Patent number: 6215878
    Abstract: A method for distributing a secret key from a key holder H to intended group members M. The method assumes that during the distribution process each party, a group member M and the key holder H, can decrypt and encrypt exchanged information such that the encrypter knows that the decrypter will be the intended party. The method preferably uses a public key/private key encryption technique in which, for example, a trusted Certificate Authority in a public key infrastructure signs the certificates to provide the public keys involved in the encryption. Alternatively, the method, together with a symmetric cipher, uses a shared secret, established in an authenticated mechanism that is outside the information exchanges of the invention. Additionally, the method uses a strong mixing function that takes several items of data as input and produces a pseudorandom authentication (or digest). Inputs to the mixing function include identity stamps that are generated by each member M and key holder H.
    Type: Grant
    Filed: February 7, 2000
    Date of Patent: April 10, 2001
    Assignee: Cisco Technology, Inc.
    Inventor: Dan Harkins
  • Patent number: 6216228
    Abstract: Provided is a method and a system for automatically controlling display of video or image data in dependence on content classification information which is integrated within the data by means of invisible digital watermarking techniques. A controller decodes the watermarked content codes and then prevents displaying of certain material, by overlaying the display with blanking data, if the codes match certain stored codes which the controller has been set to respond to. The use of invisible digital watermark codes by a controller which operates in response to the watermark codes provides reliable control since the codes are more difficult for unauthorized persons to detect and remove than other embedded codes would be.
    Type: Grant
    Filed: October 14, 1997
    Date of Patent: April 10, 2001
    Assignee: International Business Machines Corporation
    Inventors: Sydney George Chapman, Julian Hamilton Jones
  • Patent number: 6212633
    Abstract: A distributed firewall is utilized in conjunction with a memory-mapped serial communications interface such as that defined by the IEEE 1394 specification to permit secure data transmission between selected nodes over the interface. The distributed firewall incorporates security managers in the selected nodes that are respectively configured to control access to their associated nodes, thereby restricting access to such nodes to only authorized entities. Furthermore, encrypted transmissions may be supported to restrict unauthorized viewing of data transmitted between the selected nodes over the interface. Implementation of the distributed firewall does not modify any critical specifications for the memory-mapped communications interface that would prevent the selected nodes from residing on the same interface as other nodes that adhere to such specifications but that do not support secure data transmission.
    Type: Grant
    Filed: June 26, 1998
    Date of Patent: April 3, 2001
    Assignee: VLSI Technology, Inc.
    Inventors: Paul S. Levy, Steve Cornelius
  • Patent number: 6212281
    Abstract: A digital signature protocol generates a signature component using a hash of an encrypted message. The component and encrypted message form a signature pair that is forwarded to a recipient. The encryption message is used to retrieve the encryption key at the recipient and authenticate information in the message. The signature pair may be applied to a data carrier as a bar code for use in mail delivery services. By utilizing a hash of the message, a reduced message length is achieved as individual signatures are not required for each component of the message.
    Type: Grant
    Filed: October 10, 1997
    Date of Patent: April 3, 2001
    Assignee: Certicom Corp.
    Inventor: Scott A. Vanstone
  • Patent number: 6209099
    Abstract: The present invention concerns a secure data processing method and system in which the user or operator of the system can trust that all of the software and hardware components of the system have been authenticated. The invention provides a data processing system in which there is a central processor unit, memory and a security circuit in the form of an application specific integrated circuit. The security circuit has a cryptographic engine and a cryptographic key store. The cryptographic engine operates on the contents of the cryptographic key store to generate a digital signature. Means are provided to generate a digital signature from a software or hardware component to be checked for authenticity and to compare the digital signature from the component with the generated digital signature. An indication of the authenticity of the component is generated as a result of the comparison.
    Type: Grant
    Filed: July 14, 1997
    Date of Patent: March 27, 2001
    Assignee: NCR Corporation
    Inventor: Keith A. Saunders
  • Patent number: 6192130
    Abstract: A first trusted authority, such as an originating certification authority, that stores key history data, such as private decryption keys for one or more subscribers, includes a key history exportation engine operative to generate a security key history exportation packet. The security key history exportation packet contains at least encrypted security key history data uniquely associated with a subscriber. A second trusted authority, such as a destination certification authority, includes a security key history importation engine operative to decrypt the security key history exportation packet. The retrieved security key history data then is stored and made accessible through the second trust authority for later access by the subscriber. The second trusted authority serves as a new trust anchor instead of the first trust authority.
    Type: Grant
    Filed: June 30, 1999
    Date of Patent: February 20, 2001
    Assignee: Entrust Technologies Limited
    Inventor: Josanne Otway
  • Patent number: 6188767
    Abstract: The present invention encompasses a base station and method of providing communication services to a plurality of communication units. The method includes the steps of sending communication information between the base station and at least two of the plurality of communication units. A first step of identifying communication units produces a group identifier. A scrambling code, based at least in part on the group identifier, is then used to encode the communication information for transmission.
    Type: Grant
    Filed: April 29, 1998
    Date of Patent: February 13, 2001
    Assignee: Motorola, Inc.
    Inventors: Michael L. Needham, Leigh M. Chinitz, Duane C. Rabe
  • Patent number: 5887272
    Abstract: An enhanced DRAM contains embedded row registers in the form of latches. The row registers are adjacent to the DRAM array, and when the DRAM comprises a group of subarrays, the row registers are located between DRAM subarrays. When used as on-chip cache, these registers hold frequently accessed data. This data corresponds to data stored in the DRAM at a particular address. When an address is supplied to the DRAM, it is compared to the address of the data stored in the cache. If the addresses are the same, then the cache data is read at SRAM speeds. The DRAM is decoupled from this read. The DRAM also remains idle during this cache read unless the system opts to precharge or refresh the DRAM. Refresh or precharge occur concurrently with the cache read. If the addresses are not the same, then the DRAM is accessed and the embedded register is reloaded with the data at that new DRAM address.
    Type: Grant
    Filed: July 3, 1997
    Date of Patent: March 23, 1999
    Assignee: Enhanced Memory Systems, Inc.
    Inventors: Ronald H. Sartore, Kenneth J. Mobley, Donald G. Carrigan, Oscar Frederick Jones
  • Patent number: 5603061
    Abstract: A method for controlling access to a memory includes the step of defining a group of priority codes, each of which represents an order for granting simultaneous memory access requests. One of the group of priority codes is selectively provided to a memory controller. A request to access memory is then granted according to the selected priority code.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: February 11, 1997
    Assignee: NCR Corporation
    Inventors: Michael R. Hilley, William J. Kass
  • Patent number: 5361301
    Abstract: An off-premises method and apparatus for the interdiction of unauthorized channels of a broadband cable television signal includes common circuitry for adjusting the amplitude and equalization levels of the broadband CATV signals and one or more subscriber modules for generating jamming signals of different frequencies which are used to interdict one or more unauthorized channels. Each subscriber module is associated with a subscriber and is programmable and addressable to adjust the jamming parameters of that subscriber independently of other subscribers. Each subscriber module circuit comprises a plurality of latches, each of which is associated with one of a plurality of digital to analog converters. Each of the digital to analog converters drives one or more frequency agile oscillators with its analog output to generate the jamming signals.
    Type: Grant
    Filed: September 2, 1993
    Date of Patent: November 1, 1994
    Assignee: Scientific-Atlanta, Inc.
    Inventors: Neil C. Robertson, Mark E. Schutte
  • Patent number: 5237587
    Abstract: A pseudo-noise (PN) correlation and demodulation method and apparatus, in which received signals are correlated with locally generated PN codes and correlation measurements are maintained for multiple time bins corresponding to signals received over possible multiple paths. Instead of selecting one or a small number of significant correlation measurements to control data demodulation, the method of the invention performs data demodulation over the multiple time bins, and then selects data values corresponding to significant correlation measurements and combines the selected data values, weighting them in accordance with their relative strengths a determined during correlation. Use of the invention provides improved performance in terms of signal quality and continuity in the presence of multipath conditions. Careful selection of design parameters allows the improved performance to be obtained in a compact and easily portable implementation including transmitter and receiver modules.
    Type: Grant
    Filed: November 20, 1992
    Date of Patent: August 17, 1993
    Assignee: Magnavox Electronic Systems Company
    Inventor: Ralph W. Schoolcraft
  • Patent number: 5235641
    Abstract: In an information processing system having an upper rank apparatus and an external storage device which performs transmission and reception of data between the storage device and the upper rank apparatus, at least one of encryption and decryption of the data by use of an algorithm controlled by a desired data key is performed in the external storage device, while generation, encryption and decryption of the data key are performed on the upper rank apparatus side. By this configuration, the burden of the upper rank apparatus is largely reduced and the secrecy of data stored in the external storage device can be surely kept without spoiling the throughput of the whole system.
    Type: Grant
    Filed: March 12, 1991
    Date of Patent: August 10, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Masafumi Nozawa, Akinobu Shimada, Toshifumi Nishimura, Katsuharu Kakuse, Tokuhiro Tsukiyama, Kiyoshi Yata, Yasuhiro Ishii, Kazuo Takaragi, Yasushi Kuba, Fujio Fujita
  • Patent number: 5233652
    Abstract: Selective off-premises jamming for premium CATV service is provided by using continuously running fixed-frequency oscillators (19.1-19.n) for generating jamming signals at each of a plurality of distribution locations (13). The frequency of each oscillator corresponds to the frequency of one of the premium channels. A remotely controlled switched network is provided at each distribution location for applying jamming signals only to those TV channels of the subscriber lines (14) upon which the corresponding subscriber (15) is not entitled to receive premium signals. Since jamming signals are not applied to the TV channels upon which subscribers are entitled to receive premium TV programs, there is no need for de-scrambling apparatus at the various subscriber locations. In various embodiments, the switched network may be an array of switches (20.1-20.n), an array of filter traps (32.1-32.n) or an array of parallel connected band-pass filters (41.1-41.n).
    Type: Grant
    Filed: May 26, 1992
    Date of Patent: August 3, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Zheng F. Huang, Jessica S. Wong
  • Patent number: 5228056
    Abstract: A spread spectrum communications system for use over a communications channel, including a transmitter-generic-chip-code generator, a transmitter-message-chip-code generator, an EXCLUSIVE-OR gate, a combiner, a transmitter, a receiver-generic-chip-code generator, a receiver-generic mixer, a generic-bandpass filter, a receiver-message-chip-code generator, a receiver-message mixer, a message-bandpass filter, and a synchronous detector. The transmitter-generic-chip-code generator generates a generic-chip-code signal and the transmitter-message-chip-code generator generates a message-chip-code signal. The EXCLUSIVE-OR gate spread-spectrum processes message data with the message-chip-code signal to generate a spread-spectrum signal. The combiner combines the generic-chip-code signal with the spread-spectrum-processed signal. The transmitter transmits the combined generic-chip-code signal and spread-spectrum signal, on a carrier signal over the communications channel as a spread-spectrum-communications signal.
    Type: Grant
    Filed: December 14, 1990
    Date of Patent: July 13, 1993
    Assignee: InterDigital Technology Corporation
    Inventor: Donald L. Schilling
  • Patent number: 5222137
    Abstract: A radio (100) transmits and receives encrypted signals having unencrypted key identifiers, allowing other radios having the corresponding key identifiers and encryption keys to communicate with radio (100). Prior to transmitting an encrypted message, radio (100) selects a unique key identifier automatically and uses the corresponding encryption key to encrypt the message that will be transmitted. Radio (100) transmits the key identifier in an unencrypted format with the encrypted message in order to allow other radios to determine the encryption key used in encrypting the message. When receiving an encrypted message, radio (100) uses the predetermined process stored in the radio (100) to properly select the proper encryption key for use in decrypting the incoming message.
    Type: Grant
    Filed: April 3, 1991
    Date of Patent: June 22, 1993
    Assignee: Motorola, Inc.
    Inventors: Steven T. Barrett, Kevin M. Laird, Richard E. Murray, James M. O'Connor
  • Patent number: 5216715
    Abstract: A public communication system for a plurality of communication services (ISDN) has an arrangement for the authentification of the subscriber stations (TLN A, TLN B) for the key transmission.
    Type: Grant
    Filed: December 12, 1991
    Date of Patent: June 1, 1993
    Assignee: Siemens Aktiengesellschaft
    Inventor: Wernhard Markwitz
  • Patent number: 5216693
    Abstract: A spread spectrum communications system in which one of a transmitter or a receiver uses a PN code sequence while another side uses a code sequence to which is used constant pattern signals comprising an arbitrary combination of three values of positive, negative and zero for each code of a same PN code sequence. A correlator performs cross correlation process of a code sequence to which the PN code sequence and the pattern signal have been used.
    Type: Grant
    Filed: November 13, 1991
    Date of Patent: June 1, 1993
    Assignee: Ricoh Company, Ltd.
    Inventor: Masaru Nakamura
  • Patent number: 5216712
    Abstract: A recording apparatus for recording a digital data, which includes an orthogonal transform unit for transforming the time axis of the digital data to the frequency axis on a block-by-block basis, a conversion circuit for converting the digital data from the orthogonal transform means to a digital recording data and a circuit for causing the conversion circuit to convert the digital data to a recording data which is substantially impossible to be restored to the original digital data.
    Type: Grant
    Filed: December 24, 1991
    Date of Patent: June 1, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimoda, Junko Kimura
  • Patent number: 5214704
    Abstract: Methods and apparatus for nonlinearizing modulo 2 addition based encryption by block substitution techniques which allows use of the substitution scheme with relatively simple hardware and yet makes cryptanalysis more difficult. The basic block substitution, a one to one mapping of n bit binary numbers onto themselves, is based on the fact that certain permutations of the n bit binary numbers define a block substitution by modulo 2 addition of one permuted set of numbers to another, and that a subset of these define equations having an additive relationship when viewed as vectors. This allows the simple changing of the transformation on a frequent basis. Then the equations are nonlinearized, also in an orderly and readily variable manner, so that the remainder of the set equations may no longer be generated from a limited subset of the equations. Various properties of the transformations and methods of using the same are disclosed.
    Type: Grant
    Filed: August 5, 1991
    Date of Patent: May 25, 1993
    Assignee: Teledyne Industries, Inc.
    Inventor: Lothrop Mittenthal