Secure telecommunications

• US 5,434,920 A
• Filed: 08/27/1993
• Issued: 07/18/1995
• Est. Priority Date: 12/09/1991
• Status: Expired due to Fees

• Current Assignee: University of Colorado System
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Cox, Richard V., Kaplan, Michael M.
• Primary Examiner(s): BARRON JR, GILBERTO
• Application Number:
  US08/113,376
• Time in Patent Office: 690 Days
• Field of Search: 380/9, 380/41, 380/49, 380/50, 379/243, 379/258, 379/257
• US Class Current: 380/257
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04M 2203/609 Secret communication
• CPC Class Codes: H04M 3/16 with lock-out or secrecy provision in party-line systems
• CPC Class Codes: H04M 3/42 Systems providing special services or facilities to subscribers specially adapted for wireless communication networks H04W4/00
• CPC Class Codes: H04Q 3/0016 Arrangements providing connection between exchanges

Abstract

A security node disposed in the telecommunications network connecting calling and called parties transforms information (which can be voice, data, facsimile, video and other types of calls or messages) encrypted in a first format to (a) encrypted information in a different format or to (b) non-encrypted information, and vice-versa. The node is accessible from any location connected to the network. By routing calls or messages originated by the calling party and destined for the called party via the security node, and providing appropriate control signals to the node, the information may be encrypted only over a portion of the transmission path between the parties, and clear over the remainder of the transmission path. Alternatively, the information may be encrypted in different portions of the path using different encryption algorithms. This arrangement enables the parties to obtain relatively secure communications even if only one party has a security device at the originating or terminating end, or if the parties have security devices using different handshaking protocols and encryption algorithms.

Claims

1. A method of establishing a secure communication path through a network, the path for use in coupling premise equipment of a calling party with premise equipment of a called party with use of a network node, the premise equipment of the calling party and the network node having a cryptographic system, the method comprising the steps of:

the calling party'"'"'s premise equipment transmitting first signals to the network node, the first signals for use in establishing in the network a clear communication path between the calling party'"'"'s premise equipment and the network node;

the calling party'"'"'s premise equipment transmitting second signals to the network node, the second signals for use in converting the clear communication path between the network node and the calling party'"'"'s premise equipment to a secure communication path;

the calling party'"'"'s premise equipment transmitting third signals to the network node via the secure communication path, the third signals comprising a telephone number associated with the called party for use in establishing a communications path between the network node and the premise equipment of the called party.

2. The method of claim 1 wherein the calling party'"'"'s premise equipment comprises a telephone base, a telephone microphone, and a secure telephone device coupled between the base and the microphone.

3. The method of claim 2 wherein the secure telephone device includes a keypad and wherein the third signals are generated with use of the keypad.

4. The method of claim 1 wherein the step of transmitting second signals comprises the step of the calling party'"'"'s premise equipment performing a cryptographic key exchange with the network node.

5. The method of claim 4 wherein the step of performing a cryptographic key exchange is initiated by the calling party'"'"'s premise equipment.

6. The method of claim 1 wherein the premise equipment of the called party includes a cryptographic system and wherein the communication path between the premise equipment of the called party and the network node is a secure communication path.

7. A method of establishing a secure communication path through a network, the path for use in coupling premise equipment of a calling party with premise equipment of a called party with use of a network node, the premise equipment of the calling party and the network node having a cryptographic system premise equipment of the calling party coupled to the node by a clear communication path, the method comprising the steps of:

receiving at the network node first signals from the premise equipment of the calling party, the first signals for use in converting the clear communication path to a secure communication path;

receiving at the network node via the secure communication path second signals from tho calling party'"'"'s premise equipment, the second signals comprising a telephone number associated with the called party; and

establishing a communications path between the network node and the premise equipment of the called party based on the second signals.

8. The method of claim 7 wherein the calling party'"'"'s premise equipment comprises a telephone base, a telephone microphone, and a secure telephone device coupled between the base and the microphone.

9. The method of claim 7 wherein the step of converting comprises the step of performing a cryptographic key exchange between the calling party'"'"'s premise equipment and the network node.

10. The method of claim 9 wherein the step of performing a cryptographic key exchange is initiated by the network node.

11. The method of claim 7 wherein the premise equipment of the called party includes a cryptographic system and wherein the communication path between the premise equipment of the called party and the network node is a secure communication path.