Cryptography – Particular algorithmic function encoding – Nbs/des algorithm
Patent
1992-09-09
1994-04-19
Swann, Tod R.
Cryptography
Particular algorithmic function encoding
Nbs/des algorithm
380 28, 380 31, 380 33, H04K 100
Patent
active
053053842
ABSTRACT:
An encryption/decryption device, system and method for providing secure communication over a communication channel. The encryption device includes a radio interface unit connected to a conventional radio, wherein the interface unit selectively couples a codec, signal processor and modem to the transmit and receive path during secure operation. The codec digitally encodes non-secure analog signals and places them in pulse code modulated format. The signal processor then compresses the pulse code modulated signals into voice coded and then digitally encrypted NRZ signals which are then input into the conventional radio for modulating a carrier frequency on an occupied bandwidth approved for 15 KHz to 25 KHz, or as little as 11.4 KHz, spaced channels. The modem can input the digitally encrypted signals using modified frequency modulation to place the modified digitally encrypted signals substantially within the voice passband of 300 Hz to 3200 Hz. The device, system and method incorporates a master prologue sent prior to voice information at a BPS rate different from that of the voice BPS rate. The voice information is sent in blocks with a plurality of resynchronization data frames of bits interlaced between a plurality of voice frames of bits to allow highly reliable late entry and re-entry access. A conventional repeater system can be selectively controlled by a controller device of the present invention for demodulating, error correcting and recompressing the master prologue without descrambling the digitally encoded voice information.
REFERENCES:
patent: 4167700 (1979-09-01), Coe et al.
patent: 4757536 (1988-07-01), Szczutkowski et al.
patent: 4817146 (1989-03-01), Szczutkowski et al.
patent: 4981371 (1991-01-01), Gurak et al.
patent: 5007050 (1991-04-01), Kasparian et al.
patent: 5028922 (1991-07-01), Huang
patent: 5150401 (1992-09-01), Ashby et al.
Ashby James C.
Burkhart Clark
Favors Frankie
Krause Lothar A.
Tiemann Roy G.
Chips International, Inc.
Swann Tod R.
LandOfFree
Apparatus, system and method for transmitting secure signals ove does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus, system and method for transmitting secure signals ove, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus, system and method for transmitting secure signals ove will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-26563