| 7006634 |
Hardware-based encryption/decryption employing dual ported key storage |
| Feb-28-2006 |
A system for the encryption and decryption of data employing dual ported RAM for key storage to accelerate data processing operations. The on-chip key storage includes a dual-ported memory device which... |
| 6898288 |
Method and system for secure key exchange |
| May-24-2005 |
A method for secure transmission of a data message locks, at the sender, the data message using a first lock. The locked data message is transmitted to the receiver. Next, the locked data message is double-locked,... |
| 6175639 |
Digital data encode system |
| Jan-16-2001 |
A digital data encode system for inserting water mark data into digital data signals having a series of field data by use of a water mark data inserting device, the digital data encode system has a field... |
| 5991416 |
Scrambling and descrambling circuit for a cordless telephone |
| Nov-23-1999 |
A scrambling and a descrambling circuit for cordless telephone provides a higher security level than current phone scrambling circuitry. The higher security level is accomplished by separating an audio... |
| 5778073 |
Method and device for speech encryption and decryption in voice transmission |
| Jul-7-1998 |
A digitized real voice signal is converted via complex filtering into a complex signal that is subjected to sampling rate reduction, the bandwidth of the respective complex filter corresponding to the... |
| 5528692 |
Frequency inversion scrambler with integrated high-pass filter having autozero to remove internal DC offset |
| Jun-18-1996 |
A frequency inversion scrambler in a cordless telephone utilizes an integrated high-pass filter (14) between a first stage low-pass filter (12) and modulator (16) to reduce the filter order while maintaining... |
| 5471531 |
Method and apparatus for low cost audio scrambling and descrambling |
| Nov-28-1995 |
Audio signals are descrambled by double sideband modulating the scrambled audio signal with a modulation carrier having a carrier frequency slightly above the highest audio signal present in the scrambled... |
| 5446795 |
Universal decoder for television signal scramble systems |
| Aug-29-1995 |
A universal decoder for scrambled television signals in which the signals are processed in a circuit by converting them to other frequencies and then removing the scrambling signal. One method uses one... |
| 5235640 |
Master decoder for television signal scramble systems |
| Aug-10-1993 |
A master decoder for scrambled television signals in which the signals are processed in a circuit by converting them to other frequencies and then removing the scrambling signal. One method uses one or... |
| 5018198 |
Speech privacy processing method and apparatus therefor |
| May-21-1991 |
A speech privacy processing apparatus is disclosed including: a unit for obtaining the number of coefficients commonly included in a set of coefficients obtained by Fourier transformation and corresponding... |
| 5008937 |
Scrambled-communication system using adaptive transversal filters for descrambling received signals |
| Apr-16-1991 |
In a scrambled-communication system, a transmitting station generates a scrambling noise having a periodically-recurrent series of noise patterns and scrambles an information signal by simply summing the... |
| 4949378 |
Toy helmet for scrambled communications |
| Aug-14-1990 |
A toy helmet that permits the wearer to speak as to generate unintelligible noise so far as bystanders are concerned but which can be understood by another child wearing an identical helmet. Each helmet... |
| 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)... |
| 4817141 |
Confidential communication system |
| Mar-28-1989 |
The respective feature parameters extracted from a speech signal is converted into the corresponding line spectrum data in a first frequency band obtained by dividing the speech signal frequency band.... |
| 4723246 |
Integrated scrambler-encoder using PN sequence generator |
| Feb-2-1988 |
Simplified method and apparatus for performing integrated scrambling and encoding or descrambling and decoding of block code digital transmissions is disclosed. The method involves setting the scrambling... |
| 4623918 |
Pay television system utilizing multi-frequency passive filters |
| Nov-18-1986 |
Selected interference frequency signals are inserted into the video or RF signal at the transmitter for scrambling purposes, either singly or in pairs. At the receiving end the signals are decoded by use... |
| 4519083 |
Bilateral digital data transmission system |
| May-21-1985 |
A digital data transmission system for transmitting digital data from digital data handling hardware over a transmission line by analog signal representation and for receiving analog signal representation... |
| 4228321 |
Privacy transmission system with remote key control |
| Oct-14-1980 |
In the prior art key control signals are produced at a scrambling location, used at that location for scrambling and then transmitted along with the scrambled message to the unscrambling location. In accordance... |
| 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... |
| 4206462 |
Secure communication and ranging system |
| Jun-3-1980 |
15. In a secure communication system a transmitter comprising first means to modulate a carrier wave with a sub-carrier wave and a desired signal, a code generator synchronized to said sub-carrier wave,... |
| 4058677 |
Sound scrambling equipment |
| Nov-15-1977 |
Intelligence, such as voice signals, is scrambled for secrecy communication by translating the frequency spectrum of the intelligence by mixing the signals within the frequency spectrum with a local oscillator... |
| 3967067 |
Secret telephony |
| Jun-29-1976 |
1. In a system of secret transmission of speech, means to subdivide speech waves constituting a message into a plurality of narrow frequency bands, means to integrate the energy in each band, means individual... |
| 3936749 |
Matched filter communication systems |
| Feb-3-1976 |
In a wideband matched filter communication system for transmitting digital nformation identified by initial sharp pulses from a transmitter thru a communication channel to a receiver, a filter network... |
