| 6970561 |
Encryption and decryption with endurance to cryptanalysis |
| Nov-29-2005 |
An encrypting apparatus includes an encrypting operation section, a determining section and a control section. The encrypting operation section carries out an encrypting operation to a plaintext using... |
| 6873707 |
Hardware-based encryption/decryption employing cycle stealing |
| Mar-29-2005 |
A system for the encryption and decryption of data employing cycle stealing to accelerate data processing operations. The cycle stealing is employed by using level sensitive latches in a microcode controller... |
| 6393126 |
System and methods for generating trusted and authenticatable time stamps for electronic documents |
| May-21-2002 |
A trusted time infrastructure system provides time stamps for electronic documents from a local source. The system comprises a trusted master clock, a trusted local clock, and a network operations center.... |
| 6320965 |
Secure watermark method and apparatus for digital signals |
| Nov-20-2001 |
Watermark data is encoded in a digitized signal by forming a noise threshold spectrum which represents a maximum amount of imperceptible noise, spread-spectrum chipping the noise threshold spectrum with... |
| 6249583 |
On-line signal processing method |
| Jun-19-2001 |
A method for encryption and decryption of analog signal, wherein encryption and decryption are performed in analog domain. The transmitter creating digital representations with unique behavior; producing... |
| 6182214 |
Exchanging a secret over an unreliable network |
| Jan-30-2001 |
Threshold cryptography (secret sharing) is used for exchanging a secret between a server and a client over an unreliable network. Specifically, a secret is computationally divided into N shares using a... |
| 6072873 |
Digital video broadcasting |
| Jun-6-2000 |
In order to implement the Digital Video Broadcasting descrambling algorithm in the context of MPEG compressed data streams containing interleaved sections of scrambled and unscrambled data, at a data rate... |
| 6032258 |
Apparatus and methods for transmission security in a computer network |
| Feb-29-2000 |
A method for validating a message packet communicated from a source node to a destination node in a computer network is disclosed. The source node and destination node have access to a clock mechanism... |
| 5999566 |
Method and apparatus for providing error-tolerant communication of information |
| Dec-7-1999 |
The device and method according to the present invention permute the order of signals representing information intended for transmission over a communication medium. The signal ordering is permuted prior... |
| 5933431 |
Frame-based modulus interleaver |
| Aug-3-1999 |
The frame based modulus interleaver is used in a digital communications system. The interleaver uses an algorithm which insures that all of the data blocks which are present in the each input frame are... |
| 5892899 |
Tamper resistant methods and apparatus |
| Apr-6-1999 |
In accordance with a first aspect of the present invention, a security sensitive program that operates with a secret is made tamper resistant by distributing the secret in space as well as in time. In... |
| 5892775 |
Method and apparatus for providing error-tolerant storage of information |
| Apr-6-1999 |
The device and method according to the present invention permute the order of signals representing information intended for storage in a memory. The signal ordering is permuted prior to or at the time... |
| 5818934 |
Method and apparatus for providing a cryptographically secure interface between the decryption engine and the system decoder of a digital television receiver |
| Oct-6-1998 |
A method for providing a secure interface between a decryption engine and a system decoder of a digital receiver, e.g., an MPEG-2 digital television receiver. The system decoder receives an encrypted bitstream... |
| 5535275 |
Apparatus and method for producing scrambled digital video signals |
| Jul-9-1996 |
Unauthorized copying of a video signal is prevented by means of a compression encoding circuit that selectively applies scrambling to the encoded signal. The compression encoding circuit is of the type... |
| 5335275 |
Television scrambler |
| Aug-2-1994 |
A video encryption/decryption system in which lines of video information are stored in digitised form in a block of RAM memory, and are typically shuffled in groups of 32 lines by pivot reading information... |
| 5303302 |
Network packet receiver with buffer logic for reassembling interleaved data packets |
| Apr-12-1994 |
A network controller receives encrypted data packets in the form of interleaved streams of cells, and stores the received cells in a buffer until the end of each packet is received, at which time the complete... |
| 5253296 |
System for resisting interception of information |
| Oct-12-1993 |
A time segment scrambling information encoding and decoding system wherein a multiplicity of scrambling algorithms are stored in a memory such as a ROM for use during transmission via a chosen medium and... |
| 5208857 |
Method and device for scrambling-unscrambling digital image data |
| May-4-1993 |
A method and device are disclosed for scrambling-unscrambling digital image data. The data is subjected to processing for extracting the colorimetric components of the pixels forming the image, the components... |
| 5206906 |
Video scrambling system |
| Apr-27-1993 |
At least one new video signal is created by using portions taken from each signal of a plurality of original video signals to create at least one new video signal, with the sequencing of the assignments... |
| 5161191 |
Encryption system for time division multiplexed networks |
| Nov-3-1992 |
An encryption system is provided for interfacing a time division multiplexing (TDM) telecommunications arrangement with an encryption device for the scrambling of data received by the telecommunications... |
| 4965827 |
Authenticator |
| Oct-23-1990 |
An authenticator for digital data is derived by generating a numerical array, using a secret key to controllably shift the relative positions of the elements of the array, and applying the scrambled array... |
| 4937867 |
Variable time inversion algorithm controlled system for multi-level speech security |
| Jun-26-1990 |
A method for scrambling speech such as in a mobile land based communication system is disclosed. Essentially, variable length time samples of digitized speech are stored and time inversion scrambled. The... |
| 4905278 |
Scrambling of analogue electrical signals |
| Feb-27-1990 |
In a system in which an audio signal is scrambled by being divided into blocks each comprising a plurality of segments, and the segments are re-ordered within the blocks to provide the scrambled signal,... |
| 4852166 |
Analogue scrambling system with dynamic band permutation |
| Jul-25-1989 |
An analogue scrambling system with dynamic band permutation in which the speech signal is filtered (1), sampled (2) at the rate f.sub.e, digitized (3), transformed by means of an analysis filter bank (4)... |
| 4827513 |
Communications system |
| May-2-1989 |
A communications scrambler operates on a digital basis in which digital or digitized incoming and outgoing signals are merged (60) into a single bit stream for application to a binary bit store (12) and... |
| 4811394 |
Variable starting state scrambling circuit |
| Mar-7-1989 |
PN sequence generators used in the scrambling and descrambling circuits at remote locations are periodically preset to the same value in order to maintain synchronism, with the preset value being also... |
| 4773092 |
Speech scramblers |
| Sep-20-1988 |
A band scrambler which processes only time domain samples is described. The band scrambler has the effect of dividing the input signal spectrum into N sub-bands. The N sub-bands are permuted such that... |
| 4771455 |
Scrambling apparatus |
| Sep-13-1988 |
The present invention relates to a scrambling apparatus and particularly to a scrambling apparatus in which a scrambling signal is inserted into a main signal in a predetermined period (period of duration... |
| 4750205 |
Frequency or time domain speech scrambling technique and system which does not require any frame synchronization |
| Jun-7-1988 |
The present invention relates to speech scrambling techniques and systems and in particular to a frequency or time domain speech scrambling technique and system which does not require any frame synchronization.... |
| 4731839 |
Method for coding and de-coding audio and video information |
| Mar-15-1988 |
There is described a method for coding and de-coding in an information-transmission system, particularly for pay-television, which comprises for coding, converting the input analog signal into a digital... |
| 4683586 |
Scrambling system for an audio frequency signal |
| Jul-28-1987 |
A scrambling system for an audio frequency signal is disclosed which employs a timebase-compressing and/or expanding system to measure the compressed and/or expanded amount of a segment time length caused... |
| 4600941 |
Scrambling system for audio frequency signals |
| Jul-15-1986 |
A scrambling system for an audio frequency signal in which an audio signal is divided into blocks, each block being formed of a plurality of frames, the plurality of frames are rearranged on a timebase... |
| 4598169 |
System for detecting a marker signal inserted in an information signal |
| Jul-1-1986 |
A system for detecting a marker signal with a predetermined pattern inserted periodically in an information signal comprises a circuit which repetitively generates window signals and successively shifts... |
| 4551580 |
Time-frequency scrambler |
| Nov-5-1985 |
Subband signals are formed each corresponding to a portion of an input signal frequency spectrum. The subband signals are partitioned into subband time segments. The subband time segment signals are permuted.... |
| 4547802 |
TV Scrambler/descrambler using serial memories |
| Oct-15-1985 |
Apparatus for scrambling and descrambling the video portion of TV signals is disclosed. The video portion of the TV signal is stored in a serial memory such as a charge coupled device. Scrambling is accomplished... |
| 4459611 |
Image conversion system |
| Jul-10-1984 |
The image converting system including an image input step or apparatus for converting an original document information into electric image signals an inputting them, an image processing step or apparatus... |
| 4443660 |
System and method for encrypting a voice signal |
| Apr-17-1984 |
A system and method are disclosed for encrypting a voice signal. The input signal is filtered to provide a signal in a first path with components in a higher frequency band and a signal in a second path... |
| 4433211 |
Privacy communication system employing time/frequency transformation |
| Feb-21-1984 |
A privacy communication system digitizes a voice signal and divides the signal into different frequency bands or time segments and shifts the bands or segments in frequency and/or time under control of... |
| 4318125 |
Solid state digital audio scrambler system for teletransmission of audio intelligence through a television system |
| Mar-2-1982 |
An audio scrambler digitally samples a continuous audio signal, scrambles the derived samples and inserts at least one scrambled sample in the unoccupied region of the video signals of a video system for... |
| 4268720 |
Scrambler speech transmission and synchronization system |
| May-19-1981 |
A system is provided for time segment scrambling speech encoding, wherein an internal key code is provided for control thereof. The scrambling and reset units are synchronized by start and reset clock... |
| 4266243 |
Scrambling system for television sound signals |
| May-5-1981 |
An audio scrambler operates on segments of audio divided from a continuous audio signal to rotate head-to-tail the string of information contained in the segment by an amount which is at pseudo-random... |
| 4232193 |
Message signal scrambling apparatus |
| Nov-4-1980 |
In a message signal scrambling apparatus, the signal is divided into elements, each of one time slot duration, and the elements are re-arranged in order so as to produce a signal scrambled in time. Each... |
| 4223182 |
Transmission of signals with privacy |
| Sep-16-1980 |
In a speech transmission system, a first privacy apparatus for making reversible alterations in speech message waves for rendering unauthorized reception of the message difficult, a second privacy apparatus... |
| 4221931 |
Time division multiplied speech scrambler |
| Sep-9-1980 |
A privacy communication system in which increased security is provided in the scrambling of speech signals. Input speech is separated into a high frequency band and a low frequency band, and each band... |
| 4217469 |
Coding and decoding apparatus for the protection of communication secrecy |
| Aug-12-1980 |
Apparatus for coding and decoding of electrical signals within a pre-established frequency band and useful for providing communication secrecy. A transmission and coding circuit and a reception and decoding... |
| 4206319 |
Tune delay scramble equipment |
| Jun-3-1980 |
1. A time-delay scramble equipment comprising, a drive motor, a combined ut commutator element and brush element, one of said input elements being mechanically coupled to said motor, said input commutator... |
| 4157453 |
Cryptographic telegram transmission system |
| Jun-5-1979 |
1. In a communication system including the representation of different characters by normally dissimilar groups of impulses, the method of enciphering a message which includes transposing the impulses... |
| 4149035 |
Method and apparatus for enciphering and deciphering audio information |
| Apr-10-1979 |
A method of, and apparatus for, enciphering and deciphering audio information which is subdivided into partial blocks along a time axis, the partial blocks being mutually interchangeable according to key... |
| 4100374 |
Uniform permutation privacy system |
| Jul-11-1978 |
A privacy communication arrangement temporally rearranges an intelligence signal to produce an uncorrelated scrambled signal. The intelligence signal is sampled at a predetermined rate and the samples... |
| 4071707 |
Process and apparatus for improving the utilization of transmisson channels through thinning out sections of the signal band |
| Jan-31-1978 |
The known process for transmitting two or more audio signals over a single transmission channel by eliminating alternate small segments from a first signal and filling the gaps with alternate small segments... |
