Secure messaging communication system

• US 7,023,997 B1
• Filed: 12/21/2000
• Issued: 04/04/2006
• Est. Priority Date: 12/21/2000
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Schier, John E.
• Primary Examiner(s): Morse, Gregory
• Assistant Examiner(s): Ho, Thomas
• Application Number:
  US09/745,461
• Time in Patent Office: 1,930 Days
• Field of Search: 713/166, 380/277, 380/280, 380/28, 380/29, 380/30, 380/228, 380/262
• US Class Current: 380/277
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation

Abstract

A secure telecommunication system 10 is provided that allows for communication between a device 14 and a receiving device 16 of encrypted data messages through a data communications network 12. The device 14 utilizes an encryption decryption engine 30 which is operable to execute a plurality of encryption algorithms. The encryption algorithms can be accessed using a key value that is used to access an encryption selection table 28. The encryption selection table 28 can indicate a number of encryption algorithms to be applied in sequence.

Claims

1. A method for communicating a data message, comprising:

selecting a table key value in an encryption selection table based on an index that is a function of a periodic key value and a public variable key value, the encryption selection table specifying at least one of a plurality of encryption methods to be used to encrypt a data message, the table key value associated with at least one of the plurality of encryption methods;

encrypting the data message using the encryption method associated with the table key value; and

transmitting the encrypted data message over a data communication network.

2. The method of claim 1 and further comprising:

receiving a periodic key value and a public variable key value at a communication device storing the encryption selection table; and

calculating the index from the public variable key value and the periodic key values.

3. The method of claim 1 and further comprising:

selecting a second encryption method also specified by the table key value from the encryption selection table; and

encrypting the data message a second time using the second encryption method prior to transmitting the encrypted message.

4. The method of claim 1 wherein the periodic key value comprises a predetermined number agreed upon between a transmitter and a recipient of the data message.

5. The method of claim 1 wherein the public variable key value comprises a numeric value which is variable and which is available to both the recipient and the transmitter of the data message.

10. The method of claim 1, wherein selecting the table key value comprises determining which table key value in the encryption selection table is approximately equal to the index.

11. The method of claim 2, wherein calculating the index comprises using a pre-determined mathematical function to calculate the index.

12. The method of claim 1, further comprising encrypting the data message with at least two encryption methods in a specific sequence as provided in the encryption selection table.

13. The method of claim 12, further comprising decrypting the data message by executing the encryption methods in an opposite sequence as provided in the encryption selection table.

6. A data communication device operable to transmit and receive data messages to and from a data communication network, the device comprising:

a central processing unit operable to interface with a user of the device through a user interface;

an encryption decryption engine under the control of the central processing unit and operable to execute a plurality of encryption programs, each of the encryption programs being different than the remainder of the plurality and each of the encryption programs operable to receive a message and to output an encrypted message;

an encryption selection table accessible using a key value, the encryption selection table specifying at least one of the plurality of encryption programs associated with each key value, wherein the key value comprises a table key value and further comprising a user interface operable to prompt a user of the device and to receive a public variable key value and a periodic key value, the table key value calculated as a function of at least one or both of the public variable key value and the periodic key value; and

a communication interface operable to transmit an encrypted message to the user of the device, the encrypted message encrypted using the at least one encryption program specified in the encryption selection table.

7. The device of claim 6 wherein the encryption selection table specifies a plurality of encryption methods to be used in sequence for each of the key values and wherein the encryption engine is operable to encrypt a data message using each of the plurality of encryption programs in sequence prior to transmitting the encrypted data message.

8. The device of claim 6 wherein the public variable key value comprises a numeric value which is variable and which is available to both the recipient and the transmitter of the data message.

9. The device of claim 6 wherein the periodic key value comprises a predetermined number agreed upon between a transmitter and a recipient of the data message.

14. A method for communicating a data message, comprising:

receiving a periodic key value and a public variable key value at a communication device storing an encryption selection table;

calculating an index from the public variable key value and the periodic key values using a pre-determined mathematical function;

selecting a table key value in the encryption selection table based on the calculated index, the encryption selection table specifying at least one of a plurality of encryption methods to be used to encrypt a data message, the table key value associated with at least one of the plurality of encryption methods;

encrypting the data message using the encryption method associated with the table key value; and

transmitting the encrypted data message over a data communication network.

15. The method of claim 14, further comprising:

selecting a second encryption method also specified by the table key value from the encryption selection table; and

encrypting the data message a second time using the second encryption method prior to transmitting the encrypted message.

16. The method of claim 14, wherein the periodic key value comprises a predetermined number agreed upon between a transmitter and a recipient of the data message.

17. The method of claim 14, wherein the public variable key value comprises a numeric value which is variable and which is available to both the recipient and the transmitter of the data message.

18. The method of claim 14, wherein selecting the table key value comprises determining which table key value in the encryption selection table is approximately equal to the calculated index.

19. The method of claim 14, further comprising encrypting the data message with at least two encryption methods in a specific sequence as provided in the encryption selection table.

20. The method of claim 14, further comprising decrypting the data message by executing the encryption methods in an opposite sequence as provided in the encryption selection table.