US 7,600,038 B2Granted

Method and apparatus for encoding security status information

AssigneeCerticom Corp.

InventorMarinus Struik

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Abstract

A method of transmitting messages from a sender to a recipient over a wireless channel, the messages including a sequence counter and a frame counter. The method comprises establishing initial values of the sequence counter and the frame counter at the sender. Initial values of the frame counter and the sequence counter are provided to the recipient. The sender sends compressed messages including the value of the sequence counter and not the frame counter and monitors for an acknowledgement of receipt by the recipient. When no acknowledgment is received, the sender sends uncompressed messages until an acknowledgement of receipt is received from the recipient. The sequence counter is incremented and the next value of the frame counter is established as the integer next larger than previous value of the frame counter which is congruent to the sequence counter modulo 256.

Claims19

Dependent claims

A method of transmitting a frame counter value from a first correspondent to a second correspondent in a data communication system, said first correspondent having a frame counter for generating said frame counter value, and said first correspondent further having a sequence counter for generating a sequence counter value, said frame counter value and said sequence counter value being stored in memory;

said method comprising steps being performed by said first correspondent and comprising:
transferring said frame counter value and said sequence counter value from said memory into a processing unit;
calculating in said processing unit a compressed representation of said frame counter value by removing from said frame counter value a component equal to said sequence counter value;
and
generating and transmitting a message over a communication link to said second correspondent in said data communication system, said message comprising said sequence counter value and said compressed representation of said frame counter value;
whereby upon receipt of said message by said second correspondent, said second correspondent may uniquely recover said frame counter value from said sequence counter value and said compressed representation of said frame counter value in said message.

3 more elements

A method of transmitting frame counter values from a first correspondent to a second correspondent in a data communication system, said first correspondent having a frame counter for generating said frame counter values, and said first correspondent further having a sequence counter for generating sequence counter values, said method comprising steps being performed by said first correspondent and comprising:

transmitting over a communication link to said second correspondent in said data system an initial frame counter value and an initial sequence counter value;
subsequently generating and transmitting messages to said second correspondent, each of said messages comprising a sequence counter value, but not a frame counter value;
whereby upon receipt of each of said messages by said second correspondent, said second correspondent may recover said frame counter value from said sequence counter value in said message and from a previously stored frame counter value;
periodically generating and transmitting to said second correspondent a message comprising both a frame counter value and a sequence counter value, the periodicity being defined by a predefined criteria.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 10/726,493Filed 4 Dec 2003 · us provisional application
Priority: 4 Dec 2002
Published: US 2004/0136527 A115 Jul 2004
Granted: 6 Oct 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification21 codes

H04L 63/0428
For providing a confidential data exchange among entities communicating through data packet networks: wherein the data content is protected, e.g.…
H04L 1/1803
Automatic repetition systems, e.g. Van Duuren systems: stop-and-wait protocols
H04L 1/1812
Automatic repetition systems, e.g. Van Duuren systems: hybrid protocols; Hybrid automatic repeat request [HARQ]
H04L 1/1867
Automatic repetition systems, e.g. Van Duuren systems: arrangements specially adapted for the transmitter end