| 5060265 |
Method of protecting a linear feedback shift register (LFSR) output signal |
| Oct-22-1991 |
The present invention discloses a method of protecting a pseudorandom (PN) signal generated by a linear Feedback Shift Register (LFSR) from cryptographic attack. This is accomplished by first receiving... |
| 5054069 |
Apparatus for scrambling/descrambling data by word-by-word processing |
| Oct-1-1991 |
A scrambling/descrambling apparatus has a data memory for storing a data word, a bit invert flag, and numerical data. A bit shift operating section performs, on receiving a bit of data to be outputted... |
| 5054067 |
Block-cipher cryptographic device based upon a pseudorandom nonlinear sequence generator |
| Oct-1-1991 |
A block-cipher cryptographic device that processes plaintext/encrypted input data with a key signal to provide encrypted/decrypoted output data. Such device includes a shift register for receiving input... |
| 5008938 |
Encryption apparatus |
| Apr-16-1991 |
An encryption circuit that operates with substantially zero delay. Using programmable keys and polynomials, the encryption algorithm can be constantly changed to thwart any unintended receiving parties... |
| 4965881 |
Linear feedback shift registers for data scrambling |
| Oct-23-1990 |
A linear feedback shift register for use as a SONET data scrambler, operating in accordance with a generating polynomial of order n corresponding to an n by n transition matrix T, comprises k storage cells,... |
| 4860353 |
Dynamic feedback arrangement scrambling technique keystream generator |
| Aug-22-1989 |
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 a clock... |
| 4817145 |
Generator for generating binary ciphering sequences |
| Mar-28-1989 |
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... |
| 4815130 |
Stream cipher system with feedback |
| Mar-21-1989 |
A cipher system in which a key is initially inserted into a shift register and the serial output of the shift register is added to the plain text message and the sum is fed back into the serial input of... |
| 4760598 |
Coded data transmission system |
| Jul-26-1988 |
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 information-containing... |
| 4531022 |
Device for generating binary digit pseudo-random sequences |
| Jul-23-1985 |
The device is associated with a logic apparatus thereto four lines are coupled for transmitting logic data having a predetermined frequency and supplying at the output thereof a multiplexed signal having... |
| 4434322 |
Coded data transmission system |
| Feb-28-1984 |
A scrambler/encryption system for randomizing an information-containing data signal for transmission and for reproducing at the receiver the information-containing data signal. The information-containing... |
| 4431865 |
Digital signal enciphering and deciphering apparatus and system |
| Feb-14-1984 |
A digital signal of n-bit words N.sub.i is enciphered into an enciphered signal of n-bit words R.sub.i. In an enciphering unit, a logic circuit delivers each enciphered word R.sub.i through a logic operation... |
| 4404426 |
Cryptographic telegraphy programming system |
| Sep-13-1983 |
1. Apparatus for producing multiple combinations of parallel output binary signals for controlling an anti-jam or other form of telegraphy system comprising four parallel feedback shift registers, a pair... |
| 4274085 |
Flexible mode DES system |
| Jun-16-1981 |
A DES (Data Encryption Standard) system utilizing an input register, control logic and output register to provide for a selection from a multiplicity of operable modes on a single chip or family of chips. |
| 4255749 |
Apparatus for converting code signal to visual display |
| Mar-10-1981 |
Apparatus for converting a train of code signals representative of a letter, number, or symbol to a visual display of such corresponding letter, number, or symbol. The train of signals includes individual... |
| 4211891 |
Method for setting code text generators in ciphering devices |
| Jul-8-1980 |
In a procedure in which data is ciphered at a transmitter by being linked with key data generated by a code text generator and is deciphered at a receiver by appropriate linkage of the ciphered data with... |
| 4195196 |
Variant key matrix cipher system |
| Mar-25-1980 |
This is a cipher system for enciphering a stream of binary data by means of a product cipher. A clear message represented in a binary data format is transformed into a cipher message by operating on each... |
| 4181816 |
Devices for combining random sequences, using one or more switching operations |
| Jan-1-1980 |
In a circuit for producing pseudo-random sequences of digits, using at least one switch to the inputs of which sequences of digits are applied, the control signals determining the connections established... |
| 4165444 |
Apparatus for electronic encypherment of digital data |
| Aug-21-1979 |
Apparatus and methods are described for finding the coefficients of minimum polynominals in a Galois field GF(2.sup.m). Such coefficients are useful in selecting tap connections for a shift register, the... |
| 4152545 |
Pulse position modulation secret communication system |
| May-1-1979 |
This invention relates to method and apparatus in accordance with which a PPM signal can be encrypted with minimum complexity, involving converting the PPM signal to an encrypted PCM signal, and converting... |
| 4034156 |
Apparatus for the identification of feedback tapes in a shift register generator |
| Jul-5-1977 |
A shift register generator feedback tap identification system in which a received code is fed to a register which detects when the code contains all 1's at which time a bit position counter and a variable... |
