Authentication method

• US 6,711,400 B1
• Filed: 10/14/1999
• Issued: 03/23/2004
• Est. Priority Date: 04/16/1997
• Status: Expired due to Fees

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Aura, Tuomas
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): Pan, Yuwen
• Application Number:
  US09/418,138
• Time in Patent Office: 1,622 Days
• Field of Search: 455/411, 455/433, 380/248, 380/249, 380/270, 380/255, 340/5.26, 340/5.74, 340/5.8, 713/169, 713/168, 713/170, 713/200, 713/171
• US Class Current: 455/411
• CPC Class Codes: H04L 63/0869 for achieving mutual authentication cryptographic mechanisms or cryptographic arrangements for mutual authentication H04L9/3273
• CPC Class Codes: H04W 12/069 using certificates or pre-shared keys

Abstract

In telecommunications systems, the traffic can be protected from eavesdropping and the use of a false identity can be prevented by verifying the authenticity of the terminal equipment by means of an authentication procedure. Verifying the authenticity of the terminal equipment is especially important in the mobile communications systems. In the authentication procedure, the network checks the authenticity of the identity stated by the subscriber device. Additionally, the subscriber device can check the authenticity of the network identity. In the systems in accordance with prior art, the secret information required for making the authentication must be transferred via unsecure transfer networks and given to the visited networks. The information makes it possible to make unlimited number of authentications in an unlimited time. In this case, an active eavesdropper may be able to acquire the information and make the authentication process without forming a connection to the subscriber'"'"'s authentication centre. The invention presents a method in which each individual authentication process is done between the mobile station and the authentication center. This means that the reliability of the network is checked in connection with every authentication, and not enough information is transferred between the network elements to make it possible to use a false identity.

Claims

1. A method for authenticating both a subscriber station and a communications network to establish a communication connection, the subscriber station having its own identity data, the method comprising:

generating a first random number in the subscriber station which is transferred along with the subscriber identity data to an authentication centre;

generating a second random number in the authentication centre which is transferred to the subscriber station,

calculating a first set of parameters in the authentication centre having first and second responses and calculating a second set of parameters in the subscriber station including first and second responses, wherein both sets of parameters are defined on the basis of the subscriber identity and at least one of said random numbers;

sending the first responses of the first set of parameters to the subscriber station;

comparing the first responses in the subscriber station, wherein if the first responses are equal then the communications network is authenticated by the subscriber station;

sending the second responses of the second set of parameters to the communications network;

comparing the second responses in the communications network, wherein if the second responses are equal then the subscriber station is authenticated by the communications network,

in which the home network has been defined for at least some subscribers, wherein

the identity data is divided into first and second parts in such a way that the first part contains the information for identifying the subscriber group and the second part identifies the subscriber within the subscriber group,

a third random number is generated in the subscriber station,

the second part of the subscriber identifier is ciphered by using a random input and a subscriber group specific key,

a message containing a partially ciphered identifier, consisting of the first part and the ciphered second part, and the used random input is sent to a network element of the communications network,

the message is routed from the communications network to the subscriber'"'"'s home network and

the identity is deciphered in the subscriber'"'"'s home network.

2. A method according to claim 1, wherein a third response, based on the subscriber identity and the random numbers is calculated both in the authentication centre and in the subscriber station, and this response is used as a cipher key in communications between the subscriber station and the communications network.

3. A method according to claim 1, wherein the second responses are compared in a network element belonging to the home communications network.

4. A method according to claim 1, wherein the second responses are compared in the authentication centre.

5. A method according to claim 1, wherein both the first and the second random numbers are used in defining the first and the second response.

6. A method according to claim 1, wherein the subscriber station is a mobile station of a mobile communications system and the communications network is a mobile communications network.

7. A method according to claim 1, in which the subscriber identity data comprises a part defining the subscriber'"'"'s home network and a part identifying the subscriber within the home network, wherein a subscriber group is a group of subscribers in one home network and the ciphered part of the identity data is the part of the identification data that defines the subscriber'"'"'s identity in the home network.

8. A method according to claim 1, in which the subscriber identity data comprises a part defining one home location register and a part identifying the subscriber within the home location register, wherein a subscriber group is a group of subscribers in one home location register and the ciphered part of the identity data is the part of the identification data that defines the subscriber'"'"'s identity in the home location register.

9. A method according to claim 1, in which the subscriber identity data comprises a part defining the subscriber group of one home location register and a part identifying the subscriber within the subscriber group, wherein the subscriber group is a defined subscriber group within one home location register and the ciphered part of the identity data is the part that defines the subscriber identity within the subscriber group.

10. A method according to claim 1, wherein the same random number generated by the subscriber station is used both for ciphering the identity and authenticating the identity.

11. A method according to claim 1, wherein the subscriber station subscribes to a home communication network which includes the at least one authentication centre and which is different to the communications network.

12. A method according to claim 1, wherein if either the subscriber station or the communications network are not authenticated, a communication connection is not established.