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4944006 |
Secure data packet transmission system and method
A bit packet communication system includes a head-end having a software implemented 16 bit shift register with a plurality of feed-forward taps and a different plurality of feedback taps for...
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4935961 |
Method and apparatus for the generation and synchronization of cryptographic keys
A method and apparatus for generating cryptographic keys for a postal manifest and for synchronizing cryptographic keys for transmitting postal data securely on a communication link is presented....
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4933971 |
Method for encrypting transmitted data using a unique key
The invention comprises a method for encrypting data for communication between a host computer and each of a plurality of remote terminals in a network. A method is provided for periodically...
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4926475 |
Data encryption key failure monitor
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...
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4897876 |
Method of and an arrangement for digital signal encryption
An improved arrangement for digital signal encrytion using a cipher algorithm in which a multi-bit key signal is used to produce a first keystream signal of coding bytes which are used in an...
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4888802 |
System and method for providing for secure encryptor key management
A system and method for storing encrypter keys in a secure manner to prevent a "debugger" or an unauthorized user of a user application from compromising the keys. A static RAM with a battery...
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4887296 |
Cryptographic system for direct broadcast satellite system
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...
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4878246 |
Method and apparatus for generating encryption/decryption key
An encryption/decryption key is generated from an identification number ID by first generating two sets of numbers from the identification number ID, based upon known expressions. The first set of...
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4860353 |
Dynamic feedback arrangement scrambling technique keystream generator
A keystream generator including at least two feedback shift register structures. Each structure has input, intermediate and output stages through which data bits are shifted serially in response to...
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4853962 |
Encryption system
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...
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4819267 |
Solid state key for controlling access to computer systems and to computer software and/or for secure communications
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...
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4809327 |
Encrtption of messages employing unique control words and randomly chosen encryption keys
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...
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4807290 |
Self-synchronizing scrambler
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...
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4803725 |
Cryptographic system using interchangeable key blocks and selectable key fragments
A cryptographic system is used for the secure transmission of digitized signals to a plurality of receivers. At the transmission end, a key consisting of two blocks, each including a plurality of...
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4797921 |
System for enciphering or deciphering data
A system for enciphering or deciphering wherein bit patterns in a binary number notation of a plurality of elements, which an irreducible polynomial in the Galois field GF (2 i ) has, are stored in...
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4797928 |
Encryption printed circuit board
An encryption printed circuit board (PCB) for use as an add on board to a host computer includes address registers, read/write controller, and data information transceiver adapted for connection to...
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4796297 |
Device for calculating a charge for a charged information signal with errors avoided in a report of the charge
The amount of money which should be charged upon reception of a pay television signal or a like information signal, is calculated by a charging device comprising a calculator (25) for calculating...
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4794644 |
Method of secured communications in a telecommunications system
The Telecommunications system includes at least two exchanges and a plurality of user equipments. Each equipment includes a store for holding a user variable data word particular to that user. Each...
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4782529 |
Decryption of messages employing unique control words and randomly chosen decryption keys
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...
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4780905 |
Computer data encryption system
There is disclosed a data encryption system for use in a computer system having at least one disc drive. A first memory is used for storing an encryption key and a second memory is used for storing...
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4771462 |
Communication port encryption/decryption method and apparatus
There is provided herein an apparatus and method of encryption/decryption which incorporates a microprocessor into security devices. A first such device is connected to the communication port of...
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4763357 |
Method and apparatus for providing secure electronic communications
A method and apparatus for providing secure electronic communications over a communications medium between first and second locations is disclosed. A data device for generating and/or receiving...
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4760599 |
Data encryptor
A data converter applicable to data communications protects messages against errors and modifications by a third party. What is required for the detection of errors and modifications is simply...
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4760600 |
Cipher system
In a cipher system used in transmission or storage of digital data, the encipherment section comprises a first modulo-2 adder for adding, bit by bit, the k-bit contents of a first shift register...
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4760598 |
Coded data transmission system
Disclosed is a scrambler/encryption system for randomizing an information-containing data signal for transmission and for reproducing the original information at a receiver. The...
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4759063 |
Blind signature systems
A cryptographic system allows, in one exemplary use, a supplier to cryptographically transform a plurality of messages responsive to secret keys; the transformed messages to be digitally signed by...
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4757535 |
System for encrypted information transmission
A system for encrypted information transmission is disclosed in which so-called recording interference is suppressed. Encryption is effected by means of a periodically recurring pseudo-noise...
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4747139 |
Software security method and systems
Encrypted digital information in a data processing system is decrypted using a key which is a word sequence. The key is generated in a hardware module which is a single chip microprocessor....
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4723283 |
Data transmission system
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...
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4712238 |
Selective-subscription descrambling
A system in a subscriber television network for enabling descrambling of a received scrambled signal on a prepaid basis and/or an impulse-purchase basis. A received mask signal uniquely related to...
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4703503 |
Cryptographic system using pseudocomplements of vector Boolean algebra
By using properties of pseudocomplements of vector Boolean algebra defined herein, a vector Boolean value which represents a plaintext of a message is converted to an enciphered text. The...
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4688250 |
Apparatus and method for effecting a key change via a cryptographically protected link
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...
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4679236 |
Identification verification method and system
A secure system provides identification verification by transmission of an access number, preferably a random number, from a central processor to a remote terminal. The system provides portable...
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4677670 |
Paired-secure message identification controller for computers and the like
A paired-secure message identification controller for computers and the like is provided which yields secure communications between two computers with the invention installed. The message...
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4675477 |
Electronic device providing automatic permutations of a Vigenere Square
This invention relates to cryptographic teletypewriter systems and more picularly to an electronic device for use in such systems which automatically provides permutations of a Vigenere Square.
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4669089 |
Suppressed clock pulse-duration modulator for direct sequence spread spectrum transmission systems
In the disclosed digital circuit, a digital direct sequence modulation signal is converted to a suppressed clock pulse-duration modulation signal to thereby suppress the clock feature in the...
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4669118 |
Self-synchronizing descrambler
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...
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4668103 |
Polygraphic encryption-decryption communications system
A public-key system for encoding, or encrypting, digital data wherein at least two singular matrices of binary bits provide separate encrypting factors. Each matrix is a product of a common...
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4654704 |
Analog television with regenerable and encryptable signals
Novel means are disclosed for conditioning a standard color-television composite signal, such as the NISC composite, so that pictorial information is represented according to Nyquist samples which...
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4649549 |
Apparatus for synchronizing linear PN sequences
A system and method are disclosed for synchronizning the linear PN sequences contained in a received spread spectrum signal, characterized by the provision of a resident PN generator that is...
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4633037 |
Generation of identification keys
Commercial transactions conducted over a telecommunications link are verified using a transaction key available at both ends of the link. The transaction key is produced by combining (1) data...
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4555591 |
Integrated circuit devices for secure data encryption
The present invention relates to apparatus for placing digital words or a private key into a register in an integrated circuit in such a manner that it cannot be later read or modified from outside...
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4549308 |
Secure mobile radio telephony
An arrangement for generating an encryption key for use in encrypting communications between a mobile radio telephone unit and a base station is disclosed which can be readily changeable in real...
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4531020 |
Multi-layer encryption system for the broadcast of encrypted information
A method of controlling the simultaneous broadcast of enciphered digital information signals, for example in a radio or television broadcast environment, to a plurality of subscribers provides...
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4447672 |
Device for encrypting each input data bit by at least one keying bit decided by a code pattern and a bit pattern of a predetermined number of preceding encrypted bits
An encrypting device for an input data bit sequence comprises a shift register for producing a bit pattern represented by successive encrypted bits for the data bits preceding a current bit. A bit...
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4434323 |
Scrambler key code synchronizer
A method for synchronizing the scrambling sequences of communicating scrambler units of a privacy communications system in a reliable and secure manner. The method is particularly adapted for use...
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4431865 |
Digital signal enciphering and deciphering apparatus and system
A digital signal of n-bit words N i is enciphered into an enciphered signal of n-bit words R i . In an enciphering unit, a logic circuit delivers each enciphered word R i through a logic...
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4429180 |
Apparatus for simultaneous generation of key at two locations
An apparatus for simultaneously generating identical cipher key at two remote terminals in a manner which prohibits interception of the key by unauthorized persons. A circuit comprising three...
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4424414 |
Exponentiation cryptographic apparatus and method
A cryptographic system transmits a computationally secure cryptogram that is generated from a secret transformation of the message sent by the authorized transmitter; the cryptogram is again...
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4417338 |
Cryptographic key sharing circuit and method using code correction
A circuit and method for sharing a key among n individuals by distributing a secondary key to each of the n individuals such that only k of the n secondary keys are required in order to reconstruct...
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