Method and system for selecting encryption keys from a plurality of encryption keys

• US 7,254,232 B2
• Filed: 02/14/2001
• Issued: 08/07/2007
• Est. Priority Date: 02/14/2001
• Status: Expired due to Fees

• Current Assignee: Anixa Biosciences, Inc. (f/k/a ITUS Corporation)
• Original Assignee: Anixa Biosciences, Inc. (f/k/a ITUS Corporation)
• Inventors: DiSanto, Frank J., Krusos, Denis A.
• Primary Examiner(s): Barron; Gilberto
• Assistant Examiner(s): Nalven; Andrew L.
• Application Number:
  US09/782,860
• Publication Number:
  US 20020146118A1
• Time in Patent Office: 2,365 Days
• Field of Search: 380/274, 380/43, 380/262, 380/37
• US Class Current: 380/37
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation

Abstract

A method and system of alternatively selecting an encryption key used to transmit a known number data bits and providing sufficient information to inform the receiving part of the selected encryption key is presented. In one embodiment of the invention, a plurality of encryption keys are available to the parties of the communication network. The transmitting party selects an encryption key used to encrypt a message block based on the data content of a previously transmitted message block. The receiving party, having received, and decrypted, a previously transmitted message block has sufficient information to determine the encryption key used to encrypt a subsequent data block and is able to decrypt the subsequently transmitted message.

Claims

1. A method to encrypt a data message having a plurality of message data blocks prior to transmitting said message data blocks over a network, said method comprising:

extracting data values from at least two of said message data blocks;

selecting encryption keys from among a plurality of encryption keys dependently upon said extracted data values, respectively; and

,

encrypting subsequent ones of said message data blocks using said selected encryption keys, respectively.

2. The method of claim 1, wherein said extracted data value is determined using a known number of bits.

3. The method of claim 2, wherein said known number of bits are distributed among at least one data byte of said one of said message blocks.

4. The method of claim 2, wherein said known number of bits are located in a first byte of said one of said message blocks.

5. The method of claim 2, wherein said known number of bits are located in a last byte of said one of said message blocks.

6. The method of claim 1, wherein said step of extracting further comprises limiting said extracted data value to a known range.

7. The method of claim 6, wherein said known range is determined using modulo-arithmetic.

8. The method of claim 6, wherein said known range is associated with a number of said stored encryption keys.

9. A method to encrypt a data message having a plurality of message data blocks prior to transmitting said message data block over a network, said method comprising:

extracting a data value from at least one of said message data blocks;

selecting an encryption key from among a plurality of encryption keys dependently upon said extracted data value; and

encrypting at least a subsequent one of said message data blocks using said selected encryption key;

wherein said extracting, selecting and encrypting are iteratively repeated for others of said message data blocks.

10. The method of claim 9, further comprising:

receiving each of said encrypted message data blocks;

decrypting each said received, encrypted message data block using a key based on a prior received message data block;

extracting a data value from each said decrypted massage data block.

11. The method of claim 10, wherein each said received message block corresponds to at least one unencrypted message data block.

12. The method of claim 10, wherein said received message data block corresponds to a synchronizing indicator.