Plural Generators Patents (Class 380/47)
  • Patent number: 5132986
    Abstract: The present invention provides new arrangements for various components of a CSK communication system: modulator, correlators, demodulator, carrier detection circuit, and synchronization control circuit. The various improvements provide more accurate demodulation of data from the received signal in the presence of noise and signal deterioration. A modulator configuration permits the CSK system to use two M series codes in which the second code is simply a phase shifted version of the first code. The PN correlators, via shift-registers, efficiently output two correlation signals. The demodulator accepts two correlation signals from the correlators, detects auto-correlation peaks in the correlation signals, and uses the peaks to accurately determine whether the received bit has a value of "1" or "0". The carrier detecting circuit detects the presence of data in the received signal.
    Type: Grant
    Filed: December 21, 1990
    Date of Patent: July 21, 1992
    Assignee: NEC Home Electronics Ltd.
    Inventors: Kaoru Endo, Naomichi Takahashi, Soichi Tsumura
  • Patent number: 5113444
    Abstract: A cipher system is disclosed in which each character of a plaintext alphabet has associated with it a randomly distributed collection of integers of a given length. These collections of integers are secretly shared by a sender and receiver pair. The plaintext characters of a message are sequentially coded by randomly selecting representatives from the integer collections corresponding to the plaintex characters. To this sequence of concatenated integers, regarded as a single integer, is added a random integer of length equal to that of the coded-for-message integer stiring. This random integer is taken from a random digits shared by the sender and receiver. The indexing of the random integer in the digit string is transmitted as part of the cryptogram. The summed random integer plus the coding integer string is transmitted as the body of the cryptogram.
    Type: Grant
    Filed: September 5, 1990
    Date of Patent: May 12, 1992
    Inventor: Arnold Vobach
  • Patent number: 5111504
    Abstract: A field upgradeable security system deciphers signals received from a communication network. An information processor includes a receptacle for receiving a replaceable security element. The replaceable security element generates a working key necessary to the operation of the information processor. The working key is communicated to the information processor encrypted under a secret key. The information processor decrypts the encrypted working key for use in deciphering a received communication signal. Additional layers of encryption can be added to the communications between the information processor and security element to increase the level of security.
    Type: Grant
    Filed: August 17, 1990
    Date of Patent: May 5, 1992
    Assignee: General Instrument Corporation
    Inventors: James N. Esserman, Paul Moroney
  • Patent number: 5091938
    Abstract: An audiovisual subscription system includes means for aperiodically inverting the lines of a transmitted video signal on a frame-by-frame basis and for decrypting encrypted PCM audio information which is transmitted along with the aperiodically inverted video information.
    Type: Grant
    Filed: August 6, 1990
    Date of Patent: February 25, 1992
    Assignee: NEC Home Electronics, Ltd.
    Inventors: John R. Thompson, C. J. Hunting, William L. Phipps, Steven J. Raynesford, Philip H. Rittmueller
  • Patent number: 5081676
    Abstract: A hardware device containing a first permanent key and a second key is plugged in a specified port of a computer to establish a communication path between the hardware device and computer. The first and second keys are presented with an access sequence from the computer in the software which is desired to be controlled generating outputs which are applied to an algorithm decoder which provides a control key which is used to protect the software from unauthorized use. The control key is the resultant of the algorithm decoder and the first and second keys. One of the keys is supplied with the hardware under the control of the developer whereas the second key may be supplied with the hardware device but is not restricted to the hardware device and may be entered through a separate port of the computer. The algorithm decoder can be included in any part of the software, the computer hardware or any combination thereof.
    Type: Grant
    Filed: October 4, 1990
    Date of Patent: January 14, 1992
    Inventors: Wayne W. Chou, Richard Erett, Joseph M. Kulinets
  • Patent number: 5068872
    Abstract: An improved short cycled sequencer of a P-code generator is disclosed for generating a ranging code in a Global Positioning System receiver. A shift register in the sequencer has a predetermined number of stage outputs exclusive-ored with a decoded outpout of the shift register stages and the exclusive-ored output is fed back to the serial input of the shift register. At the end of sequencing through a plurality of vectors, reinitialization of the shift register occurs without having to load an initialization vector from an external source.
    Type: Grant
    Filed: November 27, 1989
    Date of Patent: November 26, 1991
    Assignee: Raytheon Company
    Inventor: John C. Schroter
  • Patent number: 5048052
    Abstract: The present invention is a spread spectrum communications system where the plural pseudonoise codes are switched such that one pseudonoise code represents binary "1" and another pseudonoise code represents binary "0" of the binary data to be transmitted. Further, in the receiver, a reference pseudonoise code is generated which is asynchronous with respect to the carrier and with respect to the pseudonoise codes of the transmitter. The reference pseudonoise code is used in a convolver to reproduce the transmitted information signal.
    Type: Grant
    Filed: February 2, 1990
    Date of Patent: September 10, 1991
    Assignee: Clarion Co., Ltd.
    Inventors: Masahiro Hamatsu, Shoichi Minagawa, Masaharu Mori
  • Patent number: 5022049
    Abstract: Apparatus for generating a complex composite code for fast acquisition by multiple access users is provided which comprises a composite code generator having an in-phase channel code generator and a quadrature channel code generator for generating two linear composite codes. The quadrature channel composite code is modulated onto a carrier which is 90.degree. out of phase with the in-phase carrier. The two linear composite codes are summed together and simultaneously transmitted to the receivers. Each receiver has a plurality of components code generators which generate replica component codes for fast acquisition of the composite code. A plurality of the components codes of the in-phase composite code are derived from the like components code generators in the quadrature channel to enhance speed of acquisition without acknowledgements by the receivers that any of the components codes have been acquired.
    Type: Grant
    Filed: November 21, 1989
    Date of Patent: June 4, 1991
    Assignee: Unisys Corp.
    Inventors: Curtis M. Abrahamson, John W. Zscheile, Jr., Vaughn L. Mower
  • Patent number: 5016276
    Abstract: A system for generating a cryptokey (k) to be shared among entities (A, B) engaged in communications, in particular one known as the key predistribution system. Indentifiers (y.sub.A, y.sub.S) for the entities engaging in communications under a center and a center algorithm (G) which only the center knows are generated, then secret algorithms (x.sub.A, X.sub.B) distinct to each entity are generated on added to IC cards or other cipher generation means (2, 3). A cipher generation means (2, 3) is provided for each entity. The identifiers (y.sub.B, y.sub.A) of the other entity are applied to compute a cryptokey, whereby a common cryptokey is generated.Also disclosed is a system for communications using the above shared cryptokey.
    Type: Grant
    Filed: May 7, 1990
    Date of Patent: May 14, 1991
    Assignee: Kabushiki Kaisha Advance
    Inventors: Tutomu Matumoto, Hideki Imai
  • Patent number: 5003598
    Abstract: A secure communication system comprising signal manipulation and inverse signal manipulation means at the sending and receiving locations respectively, the signal manipulation processes being controlled by keying signals derived according to predetermined operations from another, unrelated signal, said signal being readily and reliably available at both sending and receiving locations.
    Type: Grant
    Filed: January 23, 1989
    Date of Patent: March 26, 1991
    Inventor: George H. Kunstadt
  • Patent number: 4956863
    Abstract: A technique for use in a public key exchange cryptographic system, in which two user devices establish a common session key by exchanging information over an insecure communication channel, and in which each user can authenticate the identity of the other, without the need for a key distribution center. Each device has a previously stored unique random number Xi, and a previously stored composite quantity that is formed by transforming Xi to Yi using a transformation of which the inverse in computationally infeasible; then concatenating Yi with a publicly known device identifier, and digitally signing the quantity. Before a communication session is established, two user devices exchange their signed composite quantities, transform them to unsigned form, and authenticate the identity of the other user. Then each device generates the same session key by transforming the received Y value with its own X value.
    Type: Grant
    Filed: April 17, 1989
    Date of Patent: September 11, 1990
    Assignee: TRW Inc.
    Inventor: Kenneth C Goss
  • Patent number: 4941176
    Abstract: The invention is an apparatus and method for validating that key management functions requested for a cryptographic key by the program have been authorized by the originator of the key. The invention includes a cryptographic facility characterized by a secure boundary through which passes an input path for receiving the cryptographic service requests, cryptographic keys and their associated control vectors, and an output path for providing responses thereto. There can be included within the boundary a cryptographic instruction storage coupled to the input path, a control vector checking unit and a cryptographic processing unit coupled to the instruction storage, and a master key storage coupled to the processing means, for providing a secure location for executing key management functions in response to the received service requests. The cryptographic instruction storage receives over the input path a cryptographic service request for performing a key management function on a cryptographic key.
    Type: Grant
    Filed: August 11, 1988
    Date of Patent: July 10, 1990
    Assignee: International Business Machines Corporation
    Inventors: Stephen M. Matyas, Dennis G. Abraham, Donald B. Johnson, Ramesh K. Karne, An V. Le, Rostislaw Prymak, Julian Thomas, John D. Wilkins, Phil C. Yeh
  • Patent number: 4926475
    Abstract: An encryption key, required to encrypt and decrypt data according to a predefined algorithm is usually retained in a volatile memory device. Detection of loss of the key or corruption of the key is frequently possible only be means of the encryption circuit itself testing the key. Automated and repetitive testing of encryption keys by means of a processor or a control circuit periodically requesting the encryption circuit to test an encryption key minimizes data loss and system down time due to corrupted or lost keys.
    Type: Grant
    Filed: November 30, 1988
    Date of Patent: May 15, 1990
    Assignee: Motorola, Inc.
    Inventors: Mark G. Spiotta, Erling Bjerga
  • Patent number: 4926478
    Abstract: An authentication system in which communication between two locations is provided by a continuous full duplex bidirectional communications highway, which highway is a secure link between the two locations. Each location transmits information to the opposite location on a bit-by-bit basis, with a previously transmitted bit of information serving as a decoding key for the most recently received bit of information and said received bit in turn serving as the encoding key for the next bit to be transmitted. An authenticated transaction record is provided upon receipt of verified transactional data, and the reception of remotely received information may be authenticated to the sender of such data.
    Type: Grant
    Filed: December 30, 1988
    Date of Patent: May 15, 1990
    Inventor: Elliot L. Gruenberg
  • Patent number: 4914696
    Abstract: An intermediate scrambling device for a radiotelephone system is disclosed by which it is possible to establish and maintain scrambled communications between an originating scrambler terminal and the most distant companion scrambler on the circuit. The intermediate scrambler may establish and maintain the scrambled communications if it is the most distant scrambler, or it may become transparent to a more distant scrambler.
    Type: Grant
    Filed: August 15, 1988
    Date of Patent: April 3, 1990
    Assignee: Motorola, Inc.
    Inventors: Cary M. Dudczak, Mark W. McGuire, David T. Tennant
  • Patent number: 4912762
    Abstract: A method for simplifying key management in situations where unique cryptographic keying relationships are required end-to-end between pairs of parties and a symmetric encryption algorithm is to be used. It is useful in cases where the parties come from disjoint subsets of the total population of parties. The method provides some of the characteristics of a public key crypto system (PKS) utilizing the public identities of the parties as part of the key, but lacks the property of PKS which allows a party to independently generate a secret key which is known only to that party.
    Type: Grant
    Filed: April 18, 1988
    Date of Patent: March 27, 1990
    Assignee: International Business Machines Corporation
    Inventors: Stephen G. Lee, Peter R. Smith
  • Patent number: 4905277
    Abstract: A method for enciphering and deciphering instructions in a microcomputer and a microcomputer for effecting the same, in which, an instruction is coded into at least two types of instruction codes and stored in a storage unit and in which, under the control of discriminating circuit for discriminating the coded format, each instruction code is decoded by one of at least two decoders in accordance with one of at least two decoding formats, so that the stored software is prevented from being learned by third persons.
    Type: Grant
    Filed: April 17, 1989
    Date of Patent: February 27, 1990
    Assignee: Fujitsu Limited
    Inventor: Haruhiko Nakamura
  • Patent number: 4887296
    Abstract: A three key cryptographic system is used in the transmission of digitized signals to a plurality of receivers, each having a unique address number and a factory stored signature key which is a function of the address number. At the transmission end, a common key is generated and used to encrypt the signals to be transmitted. The signature key is generated for each receiver unit by encrypting the address number of the unit using a secret master key. The common key is then encrypted for use by each receiver using the generated signature key for that receiver. A data stream is inserted into the horizontal blanking intervals of the composite video signal. The data stream includes the encrypted signals receivable by all receivers and addressed portions, each receivable by a different receiver, containing the encrypted common key for that receiver. The receiver decrypts the common key with the stored signature key and uses it to decrypt the signals. Only a single master key must be stored and protected.
    Type: Grant
    Filed: October 16, 1987
    Date of Patent: December 12, 1989
    Assignee: Ricoh Co., Ltd.
    Inventor: Donald R. Horne
  • Patent number: 4864615
    Abstract: A key security system provides for the reproduction of secure keys by using distributed key generation data and a distributed encrypted prekey. The system encrypts program key generation data with a program key prekey in accordance with a first encryption algorithm to produce the program key; processes the program key to produce a keystream; and processes an information signal with the keystream to produce a scrambled information signal. The program key prekey is encrypted with a category key in accordance with a second encryption algorithm to produce an encrypted program key prekey. The scrambled information signal, the program key generation data and the encrypted program key prekey are distributed to descramblers.
    Type: Grant
    Filed: May 27, 1988
    Date of Patent: September 5, 1989
    Assignee: General Instrument Corporation
    Inventors: Christopher J. Bennett, Michael V. Harding, Paul Moroney
  • Patent number: 4864616
    Abstract: A method of cryptographically labeling electronically stored data is provided as part of a security system for personal computers. In protecting sensitive files of data, the labeling method utilizes a plurality of key streams, which are long, relatively prime-length sequences of random-like bytes. The key streams are related in some way to individual user and machine identifiers. Protected files of data are encrypted and decrypted by combining the key streams with the data using a reversible function, such as Exclusive OR. Each protected file has a label prefixed to it as part of the file. The label contains information necessary for encrypting and decrypting the file, controlling access to the file, and verifying integrity of the label and file. The label is permanently prefixed to the protected file but is encrypted and decrypted separately from encryption and decryption of the file.
    Type: Grant
    Filed: October 15, 1987
    Date of Patent: September 5, 1989
    Assignee: Micronyx, Inc.
    Inventors: Eugene W. Pond, Jeffrey R. Rush, John D. Watson, Bruce A. Woodall, Walter M. Goode, George E. Goode
  • Patent number: 4853962
    Abstract: A method for encrypting signals utilizes the receiver serial number to generate an index number which is used in turn to select an encryption table from among a plurality of such tables. The index number used in conjuction with any given signal is modified for greater security by adding the units digit of the signal length. Further modification of the index number can be made by adding the units digit of the time of transmission. The index number is further modified by adding a shift number by which all data characters are shifted during encryption. In signals based on a defined protocol, the shift number and the units digit of the transmission time are hidden in unused protocol positions within the signal.
    Type: Grant
    Filed: December 7, 1987
    Date of Patent: August 1, 1989
    Assignee: Universal Computer Consulting, Inc.
    Inventor: Robert T. Brockman
  • Patent number: 4850017
    Abstract: A method for controlling the use of a cryptographic key at a using station by a generating station in a network of generating and using stations is disclosed. A control value specifying the use of the cryptographic key is transmitted with a generated cryptographic key to at least two designated using stations one of which may be the generating station. Each of the generating and using stations have cryptographic facilities that securely store a master key. Two techniques are described for controlling the use of the cryptographic key. In the first, the key and the control value are authenticated via a special authentication code before use by the using station. In the second, the key and control value are coupled during key generation such that the key is recovered only if a correct control value is specified. In addition, two techniques are described for controlling who may use the cryptographic key.
    Type: Grant
    Filed: May 29, 1987
    Date of Patent: July 18, 1989
    Assignee: International Business Machines Corp.
    Inventors: Stephen M. Matyas, Jr., Carl H. W. Meyer, Bruno O. Brachtl
  • Patent number: 4845749
    Abstract: A secure audio teleconferencing system is disclosed. The secure teleconferencing system comprises a centralized facility or bridge to which a plurality of participants is connected. The role of the bridge is to receive encrypted message signals from the participants and to add the encrypted message signals, modulo some known number. The result is then transmitted to the participants. Each participant is able to decrypt the modular sum of encrypted message signals, to obtain the desired ordinary sum of clear text message signals. In accordance with the invention, the message signals remain encrypted throughtout processing by the bridge. There are no non-encrypted messages.
    Type: Grant
    Filed: December 21, 1987
    Date of Patent: July 4, 1989
    Assignee: Bell Communications Research, Inc.
    Inventors: Ernest F. Brickell, Pil J. Lee, Yacov Yacobi
  • Patent number: 4827507
    Abstract: An analog frequency inversion scrambler employing an exchange of random number seeds between an originating scrambler and an answering scrambler to create two pseudo-random frequency hopping rolling codes has been disclosed. The rolling code used in one direction of a duplex channel is different than the rolling code in the opposite direction and each code is synchronized by periodic synchronization signals.
    Type: Grant
    Filed: June 19, 1987
    Date of Patent: May 2, 1989
    Assignee: Motorola, Inc.
    Inventors: Patrick J. Marry, Gregory P. Wilson, Michael W. Houghton
  • Patent number: 4819267
    Abstract: A semiconductor device that functions as a key to control access to a computer or a software program resident in a computer or provides for secure communications is disclosed. The device executes an algorithm that combines a root and a seed to produce a password. The password is input to the computer. The computer uses an equivalent algorithm to produce a password within the computer. Comparison or other methods are employed to allow access to the computer or computer program or to allow for secure communications. The computer can be coded to produce on a video display thereof a time-space stimulus pattern which can be received by sensors of the key. Alternatively, a keypad can be employed to input the stimulus output from the computer into the access key. Further the present system allows for secure communication using algorithms between different computers and between distant locations.
    Type: Grant
    Filed: June 9, 1987
    Date of Patent: April 4, 1989
    Assignee: Thumbscan, Inc.
    Inventors: William P. Cargile, Richard D. Freeman, James M. Lyon
  • Patent number: 4817145
    Abstract: A generator for generating ciphering sequences, including plural clocked subgenerators (.GAMMA., .psi., .PSI.) which, in turn, generate binary sequences at one or several outputs. To achieve high cryptographic security of the ciphering sequence (.omega..sub.t) generated by the generator, n+1, at least three subgenerator are used in an arrangement in which the clock of n of these subgenerators (.psi., .PSI.) is controlled in each case by at least one of the outputs of the (n+1)th subgenerator (.GAMMA.) either directly or via function generators (.DELTA.f(t), .DELTA.f (t)) wherein the sequences (.mu.f(t), .mu. f(t)) generated by the n sub generators are logically combined by at least one function, which function assumes both binary states with approximately the same frequency when its arguments pass through all possible values.
    Type: Grant
    Filed: October 15, 1986
    Date of Patent: March 28, 1989
    Assignee: BBC Brown, Boveri & Company, Limited
    Inventor: Christoph-Georg Gunther
  • Patent number: 4809295
    Abstract: Apparatus and a method of generating very very long pseudonoise (PN) spread spectrum codes is provided where the code is so long that it need never repeat itself during actual use. The transmitter is adapted to start to transmit one set of a plurality of component codes as a composite code having correlation properties with the component codes. When the first set of component codes are acquired at the receiver the composite code is then transmitted as a component of a different composite code which contains the previous composite code and a second new set of component codes which have correlation properties with the new set of component codes. When the second set of component codes are acquired by the receiver the composite code is then transmitted as a third new and different composite code which contains a third new set of component codes which have correlation properties with third new set of component codes.
    Type: Grant
    Filed: April 20, 1987
    Date of Patent: February 28, 1989
    Assignee: Unisys Corporation
    Inventors: John W. Zscheile, Jr., Alan E. Lundquist, Bellie M. Spencer
  • Patent number: 4809327
    Abstract: In a communication network, a transmitting station sends encrypted messages for selective decryption in any one of several receiving stations. To that end, the transmitting station stores a single set of several encryption keys, each of which is for encrypting messages to all of the receiving stations. Also, for each message that is sent for decryption in a particular receiving station, the transmitting station (a) automatically selects at random any encryption key from the single set, (b) receives, from an input terminal, a control word which is a series of bits that uniquely identifies the particular receiving station, (c) encrypts both the message and the control word with the randomly selected key, and (d) transmits the result of step (c) to all of the receiving stations.
    Type: Grant
    Filed: September 14, 1987
    Date of Patent: February 28, 1989
    Assignee: Unisys Corporation
    Inventor: George T. Shima
  • Patent number: 4807290
    Abstract: A self-synchronizing scrambler for high bit rates comprises a plurality of scrambler stages operating in parallel and which respectively represent the series connection of a first modulo-2 adder and a second modulo-2 adder and a shift register stage, whereby the output of the shift register stage is fed back to the input of the first modulo-2 adder of its own scrambler stage and the other input of the first modulo-2 adder is connected to a further scrambler stage.
    Type: Grant
    Filed: September 25, 1985
    Date of Patent: February 21, 1989
    Assignee: Siemens Aktiengesellschaft
    Inventor: Reginhard Pospischil
  • Patent number: 4805216
    Abstract: The method and apparatus of the invention described herein provide confidential communications between two or more stations whereby the exchanged messages themselves provide the necessary enciphering keys for the messages to be encrypted and transmitted from each respective station. A full duplex communications loop is utilized between stations and the messages are exchanged substantially simultaneously.
    Type: Grant
    Filed: January 8, 1987
    Date of Patent: February 14, 1989
    Assignee: CompFax Corporation
    Inventor: Elliot L. Gruenberg
  • Patent number: 4802217
    Abstract: A security unit is disclosed for controlling access to a main computer system. The security unit provides a comprehensive mechanism for detecting and inhibiting sophisticated attackers. A method of operation and special purpose hardware for implementing this operation are disclosed.
    Type: Grant
    Filed: November 23, 1987
    Date of Patent: January 31, 1989
    Assignee: Siemens Corporate Research & Support, Inc.
    Inventor: John R. Michener
  • Patent number: 4802215
    Abstract: A conditional access system for over-air transmission and reception of scrambled television signals improves the reliability of the reception by transmitting a key signal for use in descrambling the television signal in a block of information which is itself encyphered by the key signal. On reception, the receiver after decyphering of the block of information compares the key signal recovered from the block with the key signal provided at the receiver for decyphering the block. Descrambling will only be allowed if comparison shows the two key signals to be the same. The system also provides for information relating to the credit status of each user to be transmitted over-air. In order to ensure rapid operation, the credit status signal is sent repeatedly and a further signal is appended which is used at the receiver to prevent repeated accumulation of credit.
    Type: Grant
    Filed: March 15, 1985
    Date of Patent: January 31, 1989
    Assignee: Independent Broadcasting Authority
    Inventor: Arthur G. Mason
  • Patent number: 4797672
    Abstract: A voice network security system is disclosed which provides improved security aspects in transmitting voice messages between remote locations for use in a business environment. The security aspects of the present invention serve to prevent unauthorized access to the transmitted messages.A microfiche appendix (A) of one microfiche and 41 frames is included as part of the specification (3 CFR 1.96b).
    Type: Grant
    Filed: September 4, 1986
    Date of Patent: January 10, 1989
    Assignee: Octel Communications Corp.
    Inventor: Paavo T. Kousa
  • Patent number: 4794643
    Abstract: A scrambling method for TV pictures avoids deterioration of the reproduced picture by level compressing only selected horizontal flyback portions according to a randomly selected pattern to prevent synchronization at the receiver. Key signals are added repetitively to a plurality of horizontal synch signals in one frame so as to enable descrambling of the picture at the decoder, even if noise or data error interferes with one or more of the signals.
    Type: Grant
    Filed: June 30, 1983
    Date of Patent: December 27, 1988
    Assignee: Pioneer Electronic Corporation
    Inventors: Yoshifumi Saeki, Shigeru Watanabe, Ryuichi Todoroki
  • Patent number: 4791669
    Abstract: An encryption/decryption system for a communication channel increases the number of values for the encryption key variable without increasing the length of a cipher feedback register. This is done by providing a selector to select one from many local and prestored keys for each frame. The transmitting end has a first storage register, a first memory, a first selector, and an encrypting circuit. The encrypting circuit combines a randomized signal with the input signal to form an encrypted signal. As cipher feedback, the first storage register provides bits of the encrypted signal as addresses to the first memory, which outputs corresponding random numbers. The first selector selects from the random number data to form the coding randomized signal fed to the encrypting circuit. The receiving end has a second storage register, a second memory, a second selector, and a digital signal decoding circuit. The second storage register stores bits of a received encrypted signal and outputs them in parallel as addresses.
    Type: Grant
    Filed: November 24, 1986
    Date of Patent: December 13, 1988
    Assignee: NEC Corporation
    Inventor: Kouzou Kage
  • Patent number: 4782529
    Abstract: In a communication network, a transmitting station sends encrypted messages to several receiving stations. Each receiving station stores one and the same set of decryption keys; and it stores a control word which is a series of bits that is unique to that station. Also, each receiving station identifies an encrypted message as being sent to it by -- (a) automatically selecting a decryption key at random from the set, (b) performing a decrypt operation on the same portion of the encrypted message from the transmitting station using the selected key, (c) comparing the result of the decrypt operation to its stored control word, and (d) repeating steps (a) thru (c) until either a match occurs or all keys in the set have been selected.
    Type: Grant
    Filed: September 14, 1987
    Date of Patent: November 1, 1988
    Assignee: Unisys Corporation
    Inventor: George T. Shima
  • Patent number: 4755940
    Abstract: An electronic funds transfer system (EFT) is described in which retail terminals located in stores are connected through a public switched telecommunication system to card issuing agencies data processing centers. Users of the system are issued with intelligent secure bank cards, which include a microprocessor, ROS and RAM stores. The POS includes a personal key (KP) and an account number (PAN) stored on the card when the issuer issues it to the user. Users also have a personal identity number (PIN) which is stored or remembered separately.A transaction is initiated at a retail terminal when a card is inserted in an EFT module connected to the terminal. A request message including the PAN and a session key (KS) is transmitted to the issuers data processing center. The issuer generates an authentication parameter (TAP) based upon its stored version of KP and PIN and a time variant parameter received from the terminal.
    Type: Grant
    Filed: January 6, 1987
    Date of Patent: July 5, 1988
    Assignee: International Business Machines Corporation
    Inventors: Bruno Brachtl, Christopher J. Holloway, Richard E. Lennon, Stephen M. Matyas, Carl H. Meyer, Jonathan Oseas
  • Patent number: 4747050
    Abstract: An electronic funds transfer system (EFT) is described in which retail terminals located in stores are connected through a public switched telecommunication system to card issuing agencies data processing centers. Users of the system are issued with intelligent secure bank cards, which include a microprocessor, ROS and RAM stores. The ROS includes a personal key (KP) and an account number (PAN) stored on the card when the issuer issues it to the user. Users also have a personal identity numbe (PIN) which is stored or remembered separately.A transaction is initiated at a retail terminal when a card is inserted in an EPT module connected to the terminal. A request message including the PAN and a session key (KS) is transmitted to the issuers data processing center. The issuer generates an authentication parameter (TAP) based upon its stored version of KP and PIN and a time variant parameter received from the terminal.
    Type: Grant
    Filed: August 28, 1987
    Date of Patent: May 24, 1988
    Assignee: International Business Machines Corporation
    Inventors: Bruno Brachtl, Christopher J. Holloway, Richard E. Lennon, Stephen M. Matyas, Carl H. Meyer, Jonathan Oseas
  • Patent number: 4723283
    Abstract: This invention relates to a data transmission system in which information data is shuffled and the data service is received by those who paid the charges.According to this data transmission system, a service data and a key code transmitted from a data base station are received by a decoder provided at the side of a subscriber, in which only when these data are decoded and the key code transmitted coincides with a key code at the receiving side, a particular data service transmitted from the data base station can be received by the subscriber.In the data transmission system of the invention, a control data portion transmitted is shuffled by changing a shuffling pattern by a synchronizing code inserted as part of the control data portion and by arranging the code length of the control data portion to be variable so that the content of data can not be decoded easily.
    Type: Grant
    Filed: June 20, 1986
    Date of Patent: February 2, 1988
    Assignee: Sony Corporation
    Inventors: Fumihiro Nagasawa, Kuniharu Onozuka
  • Patent number: 4707839
    Abstract: In a spread spectrum communications system employing cyclic code shift keying as its primary modulation, the transmission waveform is spread for transmission security by modulo-2 adding a pseudo-noise sequence to the CCSK data symbols prior to phase modulating onto a carrier signal for transmission. If the transmission modulation is minimum shift keying (MSK) the two components of the data stream are applied to the carrier with a differential encoding step implicit in the modulation scheme. This differential encoding characteristic makes stripping of the PN spread function prior to CCSK demodulation difficult at the receiving end. In order to demodulate this waveform in an optimum manner, an array correlator, the adjacent correlator stages of which have one chip relative time displacements of their CCSK reference waveform, is employed. In effect the array correlator becomes a parallel array of matched filters matched to each cyclic shift of the incoming waveform.
    Type: Grant
    Filed: September 26, 1983
    Date of Patent: November 17, 1987
    Assignee: Harris Corporation
    Inventors: Carl F. Andren, David A. Olaker
  • Patent number: 4688250
    Abstract: Messages sent from an earth station to a satellite by a command link are authenticated within the satellite before being executed. Authentication is accomplished by comparing a codeword appended to the message to a codeword generated within the satellite. This codeword is a cryptographic function of the message data and a secret operating key. A key change command from the earth station causes the satellite authenticator to generate a new operating key based a secret master key, a supplemental private code, and a publicly available initialization vector. The codeword appended to the key change command is encrypted in the new key and, if it agrees with a codeword generated by the satellite authenticator, the new key becomes the operating key and the key change function is complete.
    Type: Grant
    Filed: January 29, 1986
    Date of Patent: August 18, 1987
    Assignee: RCA Corporation
    Inventors: Donald G. Corrington, Stephen D. Hawkins, Daniel M. Sable
  • Patent number: 4669118
    Abstract: For the purpose of suppressing DC components and high energy components at different frequencies, digital signals are frequently transmitted in scrambled form. The realization of corresponding scramblers and descramblers is involved and difficult at high transmission rates. A self-synchronizing descrambler is provided which, due to parallel processing of the digital signals to be descrambled, has a relatively low working speed and is easy to manufacture in integrated technology. The descrambler employs a plurality of descrambler stages each including first and second modulo-2 adders and a shift register stage.
    Type: Grant
    Filed: September 25, 1985
    Date of Patent: May 26, 1987
    Assignee: Siemens Aktiengesellschaft
    Inventor: Reginhard Pospischil
  • Patent number: 4663500
    Abstract: A cryptographic system comprises a modulo-2 adder having a first input receptive of a sequence of binary digits to be scrambled and a second input receptive of a sequence of scrambling binary digits for generating a sequence of scrambled binary digits. A function generator having a memory is provided for storing a predeterminable sequence of binary digits in addressible storage locations and reading the stored binary digits in response to an address code represented by combined first and second patterns of binary digits which are generated respectively by a random pattern generator and a shift register which is connected to the output of the modulo-2 adder. The output of the function generator is the scrambling binary digits applied to the modulo-2 adder.
    Type: Grant
    Filed: June 23, 1986
    Date of Patent: May 5, 1987
    Assignee: NEC Corporation
    Inventors: Eiji Okamoto, Katsuhiro Nakamura
  • Patent number: RE33189
    Abstract: In a secure communications system, a key number which is changed periodically, e.g. monthly, and a random number from a random number generator are combined and used as a seed to reset a PN sequence generator, with the output of the generator being used to control encryption of transmission data in a signal processor. The key is also provided to a first encipherer to encipher the random number for transmission with the encrypted data. At the receiver, the key is provided on common to a decipherer for deciphering the random number and a PN sequence generator which is periodically reset by the combination of the key and random number in the same manner as in the transmitter. The PN sequence is then used to decrypt the information. User identification codes are stored in the transmitter and are used to encipher the key, with each employing its ID code to decipher the key. The user ID codes are known only to the system operator, so that not even a particular user can know the key.
    Type: Grant
    Filed: September 18, 1989
    Date of Patent: March 27, 1990
    Assignee: Communications Satellite Corporation
    Inventors: Lin-nan Lee, Russell J. Fang