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Class Information
Number: 380/40
Name: Cryptography > Communication system using cryptography > Having plural band pass filters
Description: Subject matter which divides the signal into a plurality of subbands by filtering prior to further encryption.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7310421 |
Particular plaintext detector |
Dec. 18, 2007 |
| 7277546 |
Methods and apparatus for multi-level dynamic security system |
Oct. 2, 2007 |
| 7236595 |
Integrated optics encryption device |
Jun. 26, 2007 |
| 7006634 |
Hardware-based encryption/decryption employing dual ported key storage |
Feb. 28, 2006 |
| 6898288 |
Method and system for secure key exchange |
May. 24, 2005 |
| 6823070 |
Method for key escrow in a communication system and apparatus therefor |
Nov. 23, 2004 |
| 6175639 |
Digital data encode system |
Jan. 16, 2001 |
| 5995629 |
Encoding device |
Nov. 30, 1999 |
| 5991416 |
Scrambling and descrambling circuit for a cordless telephone |
Nov. 23, 1999 |
| 5778073 |
Method and device for speech encryption and decryption in voice transmission |
Jul. 7, 1998 |
| 5528692 |
Frequency inversion scrambler with integrated high-pass filter having autozero to remove internal DC offset |
Jun. 18, 1996 |
| 5471531 |
Method and apparatus for low cost audio scrambling and descrambling |
Nov. 28, 1995 |
| 5446795 |
Universal decoder for television signal scramble systems |
Aug. 29, 1995 |
| 5235640 |
Master decoder for television signal scramble systems |
Aug. 10, 1993 |
| 5018198 |
Speech privacy processing method and apparatus therefor |
May. 21, 1991 |
| 5008937 |
Scrambled-communication system using adaptive transversal filters for descrambling received signals |
Apr. 16, 1991 |
| 4949378 |
Toy helmet for scrambled communications |
Aug. 14, 1990 |
| 4852166 |
Analogue scrambling system with dynamic band permutation |
Jul. 25, 1989 |
| 4817141 |
Confidential communication system |
Mar. 28, 1989 |
| 4723246 |
Integrated scrambler-encoder using PN sequence generator |
Feb. 2, 1988 |
| 4623918 |
Pay television system utilizing multi-frequency passive filters |
Nov. 18, 1986 |
| 4519083 |
Bilateral digital data transmission system |
May. 21, 1985 |
| 4228321 |
Privacy transmission system with remote key control |
Oct. 14, 1980 |
| 4221931 |
Time division multiplied speech scrambler |
Sep. 9, 1980 |
| 4206462 |
Secure communication and ranging system |
Jun. 3, 1980 |
| 4058677 |
Sound scrambling equipment |
Nov. 15, 1977 |
| 3967067 |
Secret telephony |
Jun. 29, 1976 |
| 3936749 |
Matched filter communication systems |
Feb. 3, 1976 |
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