Generation of encryption key

• US 5,930,362 A
• Filed: 10/09/1996
• Issued: 07/27/1999
• Est. Priority Date: 10/09/1996
• Status: Expired due to Term

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Wireless Services Incorporated (AT&T, Inc.)
• Inventors: Daly, Brian Kevin, Owens, Leslie Dale
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/731,105
• Time in Patent Office: 1,021 Days
• Field of Search: 380/30, 380/21, 380/23, 380/25
• US Class Current: 380/277
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority

Abstract

A set of Diffie-Hellman data encryption values is generated prior to receiving a request for the data encryption values. The data encryption values are then stored in a database. The generating and storing steps are performed repeatedly thus creating a stored table of data encryption values in the database. When a new user calls to activate a mobile station, a cellular network can select from among precalculated Diffie-Hellman data encryption values immediately transmit the values to the mobile station.

Claims

1. A process for creating a plurality of Diffie-Hellman data encryption values for subsequent transmission, the process comprising the steps of:

(a) generating a set of data encryption values, prior to receiving a request for said data encryption values, said set of data encryption values including at least one value from the group consisting of a public modulus value N, a secret key y, and a primitive element g; and

(b) storing said set of data encryption values in a databases;

wherein step (a) and step (b) are performed repeatedly, thus creating a stored table of sets of said data encryption values in said database.

2. The process according to claim 1, wherein:

step (a) further includes the step of calculating a partial key Y based on said public modulus N, said secret key y, and said primitive element g; and

step (b) includes the step of storing said public modulus N, said primitive element g, and said partial key Y.

3. The process according to claim 1, wherein said database is part of a cellular network.

4. The process according to claim 3, wherein said cellular network transmits data to and receives data from a mobile station, and wherein said process is used in over the air activation of said mobile station.

5. The process according to claim 3, wherein said cellular network transmits data to and receives data from a mobile station, and wherein the process further comprises the steps of:

(c) receiving a request for activation of said mobile station;

(d) selecting a current set of data encryption values from said database; and

(e) transmitting said current set of data encryption values from said cellular network to said mobile station.

6. The process according to claim 5,

further comprising the step of generating a partial key Y based on said current set of data encryption values selected in step (e);

and

wherein step (e) includes the step of transmitting said partial key Y from said cellular network to said mobile station.

7. The process according to claim 5, further comprising the steps of:

(f) receiving said current set of data encryption values from said cellular network at said mobile station;

(g) generating a secret value x at said mobile station;

(h) generating a partial key X based on said secret value x at said mobile station; and

(i) transmitting said partial key X from said mobile station to said cellular network.

8. The process according to claim 7, further comprising the step of:

(j) generating an A-key at said mobile station based on said secret key x and said current set of data encryption values.

9. The process according to claim 8, further comprising the steps of:

(k) receiving said partial key X at said cellular network; and

(l) generating an A-key at said cellular network based on said partial key x and said current set of data encryption values.

10. The process according to claim 9, further comprising the step of:

(m) comparing said A-key at said mobile station to said A key at said cellular network.

11. The process according to claim 9, wherein said mobile station includes a memory, and wherein said A-key is stored in said memory in said mobile station and in said database in said cellular network for subsequent authentication of said mobile station to said cellular network.

12. The process according to claim 7, wherein said current set of data encryption values is erased from said database after said mobile station is authenticated to said cellular network.

13. An apparatus for precalculating Diffie Hellman data encryption values, comprising:

a processor executing software instructions and generating Diffie-Hellman data encryption values prior to receiving a request for said data encryption values; and

a database coupled to said processor for storing said Diffie-Hellman data encryption values; and

a base station having an RF stage, coupled to said microprocessor, for transmitting said Diffie-Hellman data encryption values to a mobile station.

14. The apparatus according to claim 13, further comprising an encoding block, coupled to said processor, for encrypting data based on an A-Key.