Secure transmission over satellite phone network

• US 8,913,989 B2
• Filed: 02/11/2011
• Issued: 12/16/2014
• Est. Priority Date: 03/17/2004
• Status: Expired due to Fees

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Best, Fiona S., McClintock, Dorothy A., Lee, William Jeremy, Hartwell, Wesley R., Reed, Eric
• Primary Examiner(s): GESESSE, TILAHUN
• Application Number:
  US12/929,728
• Publication Number:
  US 20110237247A1
• Time in Patent Office: 1,404 Days
• Field of Search: 455/410, 455/411
• US Class Current: 455/410
• CPC Class Codes: H04B 7/18565 Arrangements for preventing unauthorised access or for providing user protection arrangements for secret or secure communication H04L9/00
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04L 63/0485 Networking architectures for enhanced packet encryption processing, e.g. offloading of IPsec packet processing or efficient security association look-up
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/30 for supporting lawful interception, monitoring or retaining of communications or communication related information circuit switched telephony call monitoring H04M3/2281
• CPC Class Codes: H04L 9/00 Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
• CPC Class Codes: H04L 9/3013 involving the discrete logarithm problem, e.g. ElGamal or Diffie-Hellman systems
• CPC Class Codes: H04M 1/2535 adapted for voice communication over an Internet Protocol [IP] network Voice over Internet Protocol (VoIP) network equipment and services H04M7/006; implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP] H04L69/16
• CPC Class Codes: H04M 1/72502 with one base station connected to a single line
• CPC Class Codes: H04M 2250/06 including a wireless LAN interface
• CPC Class Codes: H04W 12/02 Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]

Abstract

A reach back secure communications terminal includes a modem to satellite interconnect board that captures DTMF tones, demodulates encrypted modem information, and converts both into an ASCII string for presentation to a data port of a satellite phone, allowing out-of-band control of a non-secure satellite system (e.g., AT command control of a data port) by a user on a secure side of an encryption device, by including the ability to interpret control signals and control the satellite system appropriately. A false dial tone is presented to the encryption device, and the data stream coming from the encryption device is monitored for the presence of dual-tone, multi-frequency (DTMF) tones representing control signals, the DTMF tones are converted to ASCII characters, which are in turn received as control signals by the satellite phone, allowing control of the functions of the satellite system directly from the secure side of the encryption device.

Claims

1. A secure communications terminal,

comprising:

a modem interface to accept an in-band encrypted dual tone multi-frequency (DTMF) signal directed to a controlled unsecure device, and to decrypt and demodulate said DTMF signal;

a DTMF to ASCII converter module to receive a data stream from said modem interface, to convert DTMF tone to ASCII by removing in-band control signaling from said data stream; and

a data port to present said ASCII control string out-of-band to said controlled unsecure device.

2. The secure communications terminal according to claim 1, wherein:

said unsecure device is a satellite phone; and

said ASCII control string is presented to a data port of said satellite phone.

3. The secure communications terminal according to claim 1, further comprising:

an encryption device to encrypt said encrypted DTMF signal presented to said modem interface.

4. The secure communications terminal according to claim 1, wherein:

said encrypted DTMF signal is V.34 encrypted information.

5. The secure communications terminal according to claim 1, further comprising:

an unsecure satellite phone interfaced to said data port.

6. The secure communications terminal according to claim 1, wherein:

said modem interface is formed in a programmable integrated circuit (PIC).

7. A method of providing unsecure communications over a secure data network, comprising:

directing an encrypted, in-band, dual-tone multi-frequency (DTMF) signal to a secure communications terminal;

decrypting and demodulating said in-band DTMF signal;

converting said DTMF signal into an ASCII control string; and

presenting said ASCII control string out-of-band to a controlled unsecured device.

8. The method of providing unsecure communications over a secure data network according to claim 7, further comprising:

presenting said ASCII control string to a data port of a satellite phone.

9. The method of providing unsecure communications over a secure data network according to claim 7, further comprising:

producing, via an encryption device, said encrypted DTMF signal.

10. The method of providing unsecure communications over a secure data network according to claim 7, wherein:

said encrypted DTMF signal is V.34 encrypted information.

11. The method of providing unsecure communications over a secure data network according to claim 7, wherein:

said controlled unsecure device is an unsecure satellite phone, said unsecure satellite phone being controlled from a secure side of an encryption device.

12. The method of providing unsecure communications over a secure data network according to claim 7, wherein:

said unsecure device is an unsecure satellite phone, a function of said unsecure satellite phone being controlled directly from a secure side of an encryption device.