Sequence number calculation and authentication in a communications system

• US 20030069003A1
• Filed: 06/20/2002
• Published: 04/10/2003
• Est. Priority Date: 10/10/2001
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Morgan, Anne
• Granted Patent: US 7,570,764 B2
• Time in Patent Office: Days
• US Class Current: 455/411
• CPC Class Codes: H04L 9/3228 One-time or temporary data, i.e. information which is sent for every authentication or authorization, e.g. one-time-password, one-time-token or one-time-key
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 12/06 Authentication

Abstract

In a mobile communications system, a batch of sequence numbers is generated via an algorithm wherein each sequence number comprises a suffix and a prefix. The method comprises; calculating a new sequence number suffix from an existing sequence number suffix, calculating a prefix of a first new sequence number of the batch by addition to the prefix of the existing sequence number if the new suffix is not equal to a predetermined value or by a randomising process if the new suffix is equal to said predetermined value, and calculating prefixes for the other sequence numbers of the batch by modular addition of integers to the prefix of said first new sequence number. The sequence numbers are used in the authentication procedure.

Claims

1. A method of sequence number generation in a communications system wherein each sequence number comprises a suffix and a prefix, the method comprising calculating a new sequence number suffix from an existing sequence number suffix, calculating a new sequence number prefix by a randomising process if the new suffix is equal to a predetermined value, and calculating a new sequence number prefix by an algorithmic process from the prefix of the existing sequence number if the new suffix differs from said predetermined value.

2. A method as claimed in claim 1 wherein the algorithmic process comprises modular addition of an integer to the prefix of the existing sequence number.

3. A method as claimed in claim 2, wherein the integer comprises unity.

8. A home location register arranged to calculate sequence numbers via a method as claimed in claim 1.

11. Software in machine readable form on a carrier arranged to perform a method as claimed in claim 1.

4. A method of sequence number generation in a communications system wherein each sequence number comprises a suffix and a prefix, the method comprising;

calculating a new sequence number suffix from an existing sequence number suffix, calculating a new sequence number prefix by addition to the prefix of the existing sequence number if the new suffix is non-zero, and calculating a new sequence number prefix by a randomising process if the new suffix is equal to zero.

5. A method of generating a batch of sequence numbers in a communications system wherein each sequence number comprises a suffix and a prefix, the method comprising;

calculating a new sequence number suffix from an existing sequence number suffix, calculating a prefix of a first new sequence number of the batch by addition to the prefix of the existing sequence number if the new suffix is not equal to a predetermined value or by a randomising process if the new suffix is equal to said predetermined value, and calculating prefixes for the other sequence numbers of the batch by modular addition of integers to the prefix of said first new sequence number.

10. An authentication centre arranged to generate sequence numbers by a method as claimed in claim 5.

6. A set of authentication vectors constructed from a batch of sequence numbers generated by a method as claimed in claim 6.

7. An authentication signal incorporating a set of authentication vectors as claimed in claim 6.

9. A mobile handset arranged to respond to an authentication signal as claimed in claim 7.