Class 380/254 - By signal having discrete step amplitude variation

Subclass of Class 380 - Cryptography
No. of patents: 23
Last issue date: 02/26/2008

Number	Title	Issue Date
7336220	Method and apparatus for equalizing broadband chirped signal In order to generate a signal for canceling a chirped signal, a transmitter generates a cancellation signal along with the transmitted signal, using a single term variable complex gain multiplier adapted to cancel the chirped signal only at its instantaneous frequen...	02/26/2008
7317796	System and method for video stream encryption A system and method of video stream encryption. A storage device stores a first quantization scale and a second quantization scale. An encryption application receives video data, a first quantization scale and a second quantization scale, generating quantized data b...	01/08/2008
7113592	Method and device for loading input data into a program when performing an authentication A method for enhancing data security when chip cards are used for payment transactions and input data are loaded into an algorithm when performing an authentication. The security of the debit and credit data is enhanced by subdividing the data blocks and by switchin...	09/26/2006
7024175	System for masking microphonic voice signals in wired telecommunications equipment A system to thwart eavesdropping on microphonic audio signals generated by a powered telecommunications device connected to a communications line, comprising a noise generator for applying low level noise to the line, thereby masking microphonic audio signals, and a...	04/04/2006
7003118	High performance IPSEC hardware accelerator for packet classification An architecture for a high performance IPSEC accelerator. The architecture includes components for scanning fields of packets, programming an IPSEC services device according to the scanned fields, and modifying the scanned packet with an output from the IPSEC securi...	02/21/2006
6901514	Secure oblivious watermarking using key-dependent mapping functions A method for embedding a watermark into content is disclosed. The content contains content samples. The method including the steps of: receiving the content, creating a continuous watermark sequence from the watermark, and for each content sample in a first predeter...	05/31/2005
6889324	Digital measurement apparatus and image measurement apparatus A digital measurement apparatus measures a physical measurement object, provides a digital signature of public-key cryptography to measured data of a thus-measured physical quantity, and manages the measured data. The apparatus generates at least a pair of a public ...	05/03/2005
6330335	Audio steganography An identification code signal is hidden in a carrier signal (such as an electronic data signal or a physical medium) in a manner that permits the identification signal later to be discerned. The carrier signal can thereby be identified, or some machine re...	12/11/2001
6175627	Apparatus and method for embedding and extracting information in analog signals using distributed signal features Apparatus and methods are provided for embedding or embedding digital data into an analog host or cover signal. A distributed signal feature of the cover signal in a particular domain (time, frequency or space) is calculated and compared with a set of pre...	01/16/2001
5832057	Lockout device for preventing telephone eavesdropping from an extension device, and method Remote telephone coder 10R and local telephone coder 10L provide coding and decoding for voice communication between remote telephone set 11R and local telephone set 11L through telephone line 12. An eavesdropper listening in on a listening device such as...	11/03/1998
5613001	Digital signature verification technology for smart credit card and internet applications The presently used Asymmetric Digital Signature verification technologies, such as the system of RSA Data Security Corp., require complex mathematical operations for encryption and decryption. As a result, today's smart credit cards have built-in micropro...	03/18/1997
5422919	EMI suppression coding EMI suppression technique that pseudorandomizes the positive or negative going transitions that are used to represent one binary state in a transmitted digital signal such as in MLT-3 data format. By pseudorandomizing the selection of these transitions, s...	06/06/1995
5319708	System for the simultaneous coding of a number of television signals and for decoding thereof in radiofrequency A system for the simultaneous coding of a number of television signals and for decoding thereof in radiofrequency. The radiofrequency TV signal or signals to be distributed undergo remodulation on at least one channel by a signal which does not alter the ...	06/07/1994
5283807	EMI suppression coding EMI suppression technique that pseudorandomizes the positive or negative going transitions that are used to represent one binary state in a transmitted digital signal such as in an MTL-3 data format. By pseudorandomizing the selection of these transitions...	02/01/1994
5165098	System for protecting digital equipment against remote access System for protection against remote access to digital equipment (1) emitting stray electromagnetic radiation (2) and operating with digital signals under clock control and being based on the representation of a given set of characters, comprising means (...	11/17/1992
5029210	Cooperative communication system A cooperating communications system in which at least two stations and a connecting communications link form a cooperative communicating loop. Each station contains a plurality of amplification stages, which stages are selected by binary input messages. A...	07/02/1991
4932057	Parallel transmission to mask data radiation Aircraft often include a central memory which distributes data to a number of communication, navigational and other utilization devices. In order to achieve a high degree of security for data transmission from the memory to the utilization devices, data s...	06/05/1990
4737990	Unauthorized channel jamming signal applying method for CATV system In a jamming signal applying device connected between a cable and subscribers' terminal units in a CATV system, a signal for scrambling the video signal is produced in a time sharing mode, with the time sharing period being not uniform, and with sound dis...	04/12/1988
4644396	Gate circuit for central control of CATV system A gate circuit for use in switching an interference signal in a CATV system whereby the output impedance of the gate circuit is constant, independent of the switching state of the gate circuit. The inventive gate circuit includes input and output transfor...	02/17/1987
4636852	Scrambling and descrambling of television signals for subscription TV A scrambled TV signal is provided by adding thereto a signal having an amplitude which changes pseudorandomly in successive increments of time, the duration of each of which is much less than the horizontal line duration of the TV signal. This signal enco...	01/13/1987
4361729	Narrowband analog message privacy system A privacy system in which an analog information-bearing signal is linearly combined with a noiselike coding waveform to produce a composite waveform of unrecognizable, scrambled signal for transmission to an authorized system user at a remote receiving te...	11/30/1982
4208545	Secrecy system 1. In a system of secret telegraph communication, an incoming channel over which miscellaneous matter intelligence signals are periodically received, an outgoing channel susceptible of operating at a higher speed than said incoming channel, a cipher unit ...	06/17/1980
4188580	Secure communication system A secure communication system for transmitting and receiving an encoded information signal. The system generates at transmitting and receiving locations a predetermined unique pseudorandom code. A synchronized tracking signal is imposed on the information...	02/12/1980

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Class 380/254 - By signal having discrete step amplitude variation