Communication control section for facsimile equipment having a secure communication function

• US 5,241,595 A
• Filed: 06/25/1991
• Issued: 08/31/1993
• Est. Priority Date: 07/25/1990
• Status: Expired due to Term

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Kuno, Hiroshi
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US07/720,377
• Time in Patent Office: 798 Days
• Field of Search: 380/9, 380/10, 380/18, 380/21, 380/43, 380/49, 380/50, 380/20, 358/443, 358/468, 379/93, 379/95, 379/100
• US Class Current: 380/243
• CPC Class Codes: H04L 2209/12 Details relating to cryptographic hardware or logic circuitry
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04N 1/4486 using digital data encryption

Abstract

A facsimile equipment including a memory for storing a cipher key data, ten number keys for inputting the cipher key data, a DTMF signal receiving circuit for converting a DTMF signal received through a telephone line into the cipher key data, a controller for controlling the memory to selectively store the cipher key data input by means of the ten number keys or the cipher key data converted by the DTMF signal receiving circuit, a DTMF signal generating circuit for converting the cipher key data stored in the memory into a DTMF signal and generating this DTMF signal to the telephone line, and a controller for scrambling an image data to be transmitted with the cipher key data stored in the memory to provide the transmission data and for descrambling the scrambled image data received with the cipher key data stored in the memory to provide the reception data.

Claims

1. A communication control section for facsimile equipment, comprising:

memory means for storing cipher key data;

cipher key data registration means for converting a signal received through a telephone line into the cipher key data;

control means for controlling the memory means to store the cipher key data converted by the cipher data key data registration means;

means for inputting the cipher key data for storing in said memory means; and

transmission converting means for converting the cipher key data stored in the memory means into a DTMF signal and then generating the DTMF signal to a telephone lien.

2. The communication control section according to claim 1 further comprises scrambling means for scrambling an image data to be transmitted with the cipher key data stored in the memory means to provide a transmission data.

3. The communication control section as claimed in claim 1, wherein said received signal is dual tone multi-frequency (DTMF) signal.

4. The communication control section as claimed in claim 1, wherein said means for inputting the cipher key data comprises a key pad.

5. A communication control section for a facsimile machine, comprising:

mode selection means for selecting one of a scrambled mode and a plaintext mode;

memory means for storing a cipher key data set;

input means for inputting said cipher key data set into said memory means;

a communications interface for linking the facsimile machine to a communications medium;

a control means for executing one of scrambling or descrambling input image data with the cipher key data set stored in said memory means.

6. The communication control section as claimed in claim 5, wherein said input means comprises said control means inputting the cipher key data set into said memory means upon receipt from a remote facsimile machine.

7. The communication control section as claimed in claim 5, wherein said input means comprises:

a ten digit key pad for randomly inputting a predetermined number of digits when the facsimile machine is the transmitter.

8. The communication control section as claimed in claim 7, wherein said predetermined number of digits is sixteen.

9. The communication control section as claimed in claim 7, wherein said control means adds a parity code to said cipher key data set prior to transmitting data to a remote facsimile machine.

10. The communication controls section as claimed in claim 9, further comprising transmission converting means for converting the cipher key data set with added parity code into a DTMF signal and passing said DTMF signal to said communications interface.

11. The communication control section as claimed in claim 10, wherein said transmission converging means converts a received signal into said cipher key data set and parity code when the facsimile machine is in the scrambled mode.

12. The communication control section as claimed in claim 5, further comprising error detection means.

13. A communication control section for a facsimile machine, comprising:

a transmission/reception interface;

a signal generating circuit electronically connected to said transmission reception interface;

a signal receiving circuit electronically connected to said transmission/reception interface;

a mode selection key for selecting between scrambled and plaintext transmission/reception modes;

cipher key data input means for creating a set of cipher key data;

a memory for storing said cipher key data set; and

a control unit for electronically connecting said signal generating and receiving circuits, said mode selection key, said cipher key data input means and said memory wherein when the scrambled transmission/reception mode is selected by said mode selection key, said communication control section has the ability to do one of the acts consisting of sending and receiving a cipher key data set and scrambled message data.

14. The communication control section as claimed in claim 13, wherein said cipher key data set and a clear image data are integrated using an exclusive OR circuit in accordance with modulo-two addition during transmission to create the scrambled message data.

15. The communication control section as claimed in claim 13, wherein said signal generating circuit and said signal receiving circuit process dual tone multi-frequency (DTMF) signals.

16. The communication control section as claimed in claim 13, further comprising descrambling means for descrambling reception data using the cipher key data set stored in the memory to provide a descrambled copy from the scrambled message data received.