| 5574785 |
Enciphered communication system |
| Nov-12-1996 |
An enciphered communication system is provided which has a plurality of cipher keys selectively used for enciphering data, wherein even when a cipher key number used at a transmitting side is not correctly... |
| 5533123 |
Programmable distributed personal security |
| Jul-2-1996 |
The present invention is embodied in a Secured Processing Unit (SPU) chip, a microprocessor designed especially for secure data processing. By integrating keys, encryption/decryption engines and algorithms... |
| 5533126 |
Key protection device for smart cards |
| Jul-2-1996 |
This invention concerns a key protection device for smart cards and is characterized by the fact that: each input user key is coded using a random key and stored; protection data that corresponds to each... |
| 5517568 |
Method of detecting unauthorized use of a wireless communication channel |
| May-14-1996 |
A method for detecting unauthorized use of a communication unit (102) in a secure wireless communication system includes monitoring (201) a wireless communication channel (103) presently supporting a secure... |
| 5509076 |
Apparatus for securing the integrity of a functioning system |
| Apr-16-1996 |
Apparatus is provided for securing the integrity of a functioning system. The apparatus comprises a primary device for performing a function having a first vulnerability and a secondary device having a... |
| 5442703 |
Method for identifying corrupt encryption keys within a secure communication system |
| Aug-15-1995 |
A resource allocator (108) receives, from a first communication unit, a request to establish secure communications with at least a second communication unit. A key identifier is retrieved by the resource... |
| 5432848 |
DES encryption and decryption unit with error checking |
| Jul-11-1995 |
An improved DES unit internally checks whether the DES algorithm is being performed without error. A standard DES algorithm performs an initial permutation of input data and then multiple rounds or iterations... |
| 5406625 |
Receiving apparatus and recording method |
| Apr-11-1995 |
A determination is made whether recording by a recording apparatus is or is not feasible. This determination is made on the basis of whether or not scrambled reception signals can be descrambled. Recording... |
| 5379342 |
Method and apparatus for providing enhanced data verification in a computer system |
| Jan-3-1995 |
A personal computer system compatible with application programs and operating system software. The personal computer system includes a microprocessor electrically coupled to a data bus, non-volatile memory... |
| 5375169 |
Cryptographic key management method and apparatus |
| Dec-20-1994 |
A system for the secure communication of a message from a transmitting user to a receiving user using a split key scheme. Each user generates a key component using a cryptographic engine. The key component... |
| 5365591 |
Secure cryptographic logic arrangement |
| Nov-15-1994 |
A secure cryptographic logic arrangement immediately halts the processing of its internal processors upon detection of a single fault. The cryptographic logic arrangement has an arithmetic logic unit,... |
| 5357572 |
Apparatus and method for sensitive circuit protection with set-scan testing |
| Oct-18-1994 |
A set/scan test capability is provided for a circuit that includes sensitive subcircuits, but that can be latched out to prevent reverse engineering the sensitive elements. A mechanism to inhibit set/scan... |
| 5347536 |
Multipath noise reduction for spread spectrum signals |
| Sep-13-1994 |
The invention includes the concepts of early-prompt delay tracking, multipath correction of early-prompt delay tracking from correlation shape and carrier phase multipath correction. In early-prompt delay... |
| 5307409 |
Apparatus and method for fault detection on redundant signal lines via encryption |
| Apr-26-1994 |
A fault detection apparatus and method combines each of a plurality of redundant digital data signals with a unique key signal for transmission over one of a plurality of signal lines and recombines each... |
| 5305382 |
Satellite broadcast receiver |
| Apr-19-1994 |
A satellite broadcast receiver comprise a demodulator for demodulating received signals, a mode changer for changing the voice output mode, and a control that prevents a voice output mode changing operation... |
| 5303293 |
Cryptographic device with a display means for identification of a defective function in the cryptographic device |
| Apr-12-1994 |
A cryptographic device for use with a data terminal in a data network contains here a transmission channel (S) and a reception channel (E) with associated cryptogenerators and data input and output equipment,... |
| 5265164 |
Cryptographic facility environment backup/restore and replication in a public key cryptosystem |
| Nov-23-1993 |
A computer apparatus, program and method function in a data processing system to replicate a cryptographic facility. The system includes a first cryptographic facility containing a portable part which... |
| 5257311 |
System for monitoring ATM cross-connecting apparatus by inside-apparatus monitoring cell |
| Oct-26-1993 |
A system for monitoring an ATM cross-connecting apparatus by inputting a test cell through a path for a main signal into the ATM cross-connecting apparatus, and examining the cell after the cell passed... |
| 5243651 |
Diagnostic method and apparatus for a cable television interdiction system |
| Sep-7-1993 |
A diagnostic method and apparatus for a cable television interdiction system is provided. One or more diagnostic modes each corresponding to a particular problem or state associated with the interdiction... |
| 5214694 |
Scramble signal transmission system for earth station of communication satellite |
| May-25-1993 |
A system for transmitting a scramble signal for a sky port scramble system including an organization center for organizing data relating to customers etc. and first and second control units each having... |
| 5199069 |
Automatic encryption selector |
| Mar-30-1993 |
A radio (100) capable of automatically selecting an encryption algorithm from among a plurality of algorithms (122 and 124) is disclosed. The method for automatically selecting the proper encryption hybrid... |
| 5181243 |
System and method for communications security protection |
| Jan-19-1993 |
A system and method are disclosed for preventing intelligible interception of information signals transmitted over a two-direction line. A masking signal is applied through a hybrid circuit at the receiving... |
| 5179592 |
Data scrambler and descrambler capable of preventing continuous bit zeros or ones |
| Jan-12-1993 |
A data scrambler, which transmits a data sequence, includes circuitry to suppress consecutive occurrences of a predetermined number of data sequence bits having the same value. The number of consecutive... |
| 5177785 |
Method and system for secure telecommunications |
| Jan-5-1993 |
There is disclosed a method and system for injecting a number of different signal patterns onto a tone encoded telecommunications line for the purpose of preventing unauthorized eavesdropping. The system... |
| 5161186 |
System for secure and private communication in a triple-connected network |
| Nov-3-1992 |
An apparatus and method for secure and private communications in a triple-connected processor network. Communication of a message over at least three data paths is achieved by transmitting the message... |
| 5144664 |
Apparatus and method for upgrading terminals to maintain a secure communication network |
| Sep-1-1992 |
A secure communication network serves a plurality of terminals grouped into different security categories. Each terminal includes a replaceable security element containing a security algorithm specific... |
| 5099515 |
Secrecy device for wiretapping prevention and detection |
| Mar-24-1992 |
A secrecy device connected between a telephone handset and a telephone body, which comprises a secrecy circuit for modulating a voice signal received from the handset on a predetermined modulation system... |
| 5077791 |
Method and apparatus for preventing unauthorized transmissions |
| Dec-31-1991 |
Each subscriber unit (108) operating on a communication system (100) selects either encrypted or unencrypted transmission mode as a current transmission mode. Before participating in a communication, each... |
| 5063595 |
Optical communications network |
| Nov-5-1991 |
A passive, all optical communications network is provided in which a single optical source in a central station serves many outstations (e.g., telephones in customers' premises). Time division multiplexed... |
| 5029184 |
Low probability of intercept communication system |
| Jul-2-1991 |
A low probability of intercept communication system (CCSK)--modulates information signals onto an inverse fast Fourier transformation of a large number of simultaneous frequencies that have been determined... |
| 5022076 |
Redundant encryption processor arrangement for use in an electronic fund transfer network |
| Jun-4-1991 |
An improved fault tolerant processor arrangement is described. In accordance with this invention, redundant processors are coupled in parallel in a master/slave configuration wherein means are provided... |
| 4997288 |
Power supply arrangement for fault-tolerant operation in a microcomputer-based encryption system |
| Mar-5-1991 |
An improved fault-tolerant arrangement for use in a multichannel data encryption unit is disclosed. In accordance with the teachings of this invention, a data encryption system includes a plurality of... |
| 4987594 |
Stand-alone utility device with antitheft code with method for its use |
| Jan-22-1991 |
A stand-alone utility device for perceptible reproduction of signals, for example a radio receiver or a TV receiver, is protected from theft because the reproduction quality of the signals is disturbed... |
| 4977593 |
Optical communications network |
| Dec-11-1990 |
A passive, all optical communications network is provided in which a single optical source in a central station serves many outstations (e.g. telephones in customers' premises). Time division multiplexed... |
| 4972478 |
Soft logic cryptographic circuit |
| Nov-20-1990 |
A soft logic cryptographic circuit that can be reprogrammed with various cipher algorithms. The cryptographic circuit can be manufactured in a non-secure environment because a security sensitive cipher... |
| 4972469 |
System and method for communications security protection |
| Nov-20-1990 |
A system and method are disclosed for preventing intelligible interception of information signals transmitted over a two-direction line. A masking signal is applied through a hybrid circuit at the receiving... |
| 4961221 |
Communication method and system with encryption of information |
| Oct-2-1990 |
An information encryption method particularly intended for a communication system in which bidirectional multiplexed communications of the point-to-multipoint type are derived between a switching exchange... |
| 4937861 |
Computer software encryption apparatus |
| Jun-26-1990 |
Data security is provided using an encryption/decryption algorithm which attaches at the primitive BIOS level of the operating system automatically during the power-on self-test routines. The encryption/decryption... |
| 4926475 |
Data encryption key failure monitor |
| May-15-1990 |
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... |
| 4910772 |
Video scrambling apparatus and method based on space filling curves |
| Mar-20-1990 |
A method of encrypting a video signal employing a pseudo-random Space Filling Curve having a highly irregular scanning pattern for scanning the pixel addresses of a video picture stored in a frame buffer.... |
| 4864612 |
Method of avoiding accidental actuation of maintenance equipment in a communications network |
| Sep-5-1989 |
A technique for avoiding accidental actuation of communications system devices which respond to a predetermined pattern of signals. In accordance with the present invention, data to be transmitted through... |
| 4803351 |
IC card system with control of data-writing process |
| Feb-7-1989 |
An IC card system comprises an IC card terminal and an IC card which is inserted into the terminal, the terminal including a power-supply circuit for supplying data-writing power to a memory provided in... |
| 4802216 |
Interrogator and transponder test equipment |
| Jan-31-1989 |
Test equipment is described for testing a transponder and an interrogator positioned in close proximity to one another to cause suppression of its receivers while either transponder or interrogator is... |
| 4776010 |
Power supply control circuit in subscriber's terminal for control unit in subscriber's communication system |
| Oct-4-1988 |
A subscriber's terminal is connected by a cable to a control unit, which is connected to a central station by a cable. The subscriber's terminal has a voltage supply source for supplying power to the control... |
| 4760586 |
Spread spectrum communication system |
| Jul-26-1988 |
Disclosed is a spread spectrum communication system realized by using the frequency hopping coherent detection system wherein such an offset voltage pattern is predetermined by a polynomial is applied... |
| 4752954 |
Upstream signal control apparatus in bidirectional CATV system |
| Jun-21-1988 |
A CPU in a subscriber terminal generates upstream data and a transmission request signal as an enable signal for sending the upstream data to a broadcast center. An oscillator generates a carrier wave... |
| 4673976 |
Cable television system data verification apparatus |
| Jun-16-1987 |
In a cable television system in which the individual subscriber's converter/tuner is located outside the subscriber's premises in an external control unit ("ECU") and controlled remotely via a subscriber... |
| 4645871 |
Non-interfering in-band protocol-independent diagnostic scanning in a digital multipoint communication system |
| Feb-24-1987 |
In a system in which data between a master and remote location is encrypted by using the DES algorithm, the status of security devices at the remote location is monitored from a centralized security station.... |
| 4639548 |
Digital communication system including an error correcting encoder/decoder and a scrambler/descrambler |
| Jan-27-1987 |
An error correction code data communication system scrambles and descrambles both non-coded data and coded data by using substantially the same code process at the opposite ends of a transmission path.... |
| 4635223 |
Fail safe protection circuitry for a commerical microprocessor in encryption equipment |
| Jan-6-1987 |
In conjunction with a commercial microprocessor controlled by a program stored in a ROM, a second microprocessor, similar to the first microprocessor, is connected into the system so as to operate similar... |
