	US 7,526,274 B2
	Authentication method in data communication and smart card
Eddy Bernard, Montrouge (France); and Stéphanie Salgado, Montrouge (France)
Assigned to Axal to S.A, Meudon Cedex (France)
Appl. No. 10/571,216 PCT Filed Aug. 30, 2004, PCT No. PCT/IB2004/002815 § 371(c)(1), (2), (4) Date Mar. 08, 2006, PCT Pub. No. WO2005/025178, PCT Pub. Date Mar. 17, 2005.
Claims priority of application No. 03292219 (EP), filed on Sep. 09, 2003.
Prior Publication US 2007/0005986 A1, Jan. 04, 2007
Int. Cl. H04M 1/66 (2006.01); H04M 1/68 (2006.01); H04M 3/16 (2006.01)

U.S. Cl. 455—411

4 Claims

1. An authentication method for use in a system including a first entity and a second entity mutually communicating by way of a network, wherein said first entity is adapted to authenticate said second entity and data received from said second entity, and wherein both first and second entities store the same secret key, said authentication method comprising the steps of:

receiving by said first entity a message authenticating code and authentication function parameters, said message authenticating code being a function of said secret key and said authentication function parameters;

determining by said first entity, from a sequence number included in said authentication function parameters, whether said message authenticating code and authentication function parameters have already been received by said first entity, wherein authentication is aborted without updating a failure counter in said first entity when said sequence number indicates that said message authenticating code and authentication function parameters have already been received by said first entity;

computing by said first entity an expected code as a function of said authentication function parameters which have been received and said secret key stored in said first entity;

comparing by said first entity said message authenticating code received and said expected code;

aborting authentication when the message authenticating code received and the expected code do not match; and

updating in said first entity said failure counter every time the message authenticating code received and the expected code do not match upon comparison by said first entity.