# US 7,466,976 B2 · Method for securing data traffic between mobile radio network and IMS network

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 7,466,976 B2
- Document ID: US7466976B2
- Status: Granted
- Kind: B2
- Application number: 10/575,884
- Filed: 2004-10-13
- Published: 2007-06-21
- Granted: 2008-12-16
- Earliest claimed: 2003-10-14
- Assignees: Siemens Aktiengesellschaft
- Inventors: Dirk Kröselberg
- Web page: https://patentgrep.com/patent/US7466976B2

## CPC

- H04L 63/0435: {wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06)}
- H04L 63/06: {for supporting key management in a packet data network (cryptographic mechanisms or cryptographic arrangements for key management H04L9/08)}
- H04L 63/08: {for authentication of entities (cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32)}
- H04L 63/0807: {using tickets, e.g. Kerberos (cryptographic mechanisms or cryptographic arrangements for entity authentication using tickets or tokens H04L9/3213)}
- H04W 12/041: Key generation or derivation
- H04W 12/06: Authentication
- H04L 63/083: {using passwords (cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226)}
- H04L 65/1016: IP multimedia subsystem [IMS]
- H04W 8/26: Network addressing or numbering for mobility support
- H04W 80/10: adapted for {application} session management, e.g. SIP [Session Initiation Protocol] {(connection management H04W76/00; arrangements for session management H04L67/14)}
- H04W 92/02: Inter-networking arrangements
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Data traffic between a mobile radio network and an IMS network is secured by first authenticating a mobile subscriber in the mobile radio network and in the IMS network. Next, an examination is carried out to check whether the identity of the mobile subscriber authenticated in the IMS network corresponds to the identity of the subscriber authenticated in the mobile radio network. If so, a confirmation message is sent from the IMS network to the mobile subscriber in the even of corresponding identities and a data exchange is carried out between the mobile subscriber and the IMS network by a security protocol protected by a common key derived from the confirmation message.

## Claims

### Claim 1

A method for user authentication and securing data traffic between a mobile radio network and an Internet protocol-based multimedia subsystem network, comprising:
authenticating a mobile subscriber in the mobile radio network;
authenticating the mobile subscriber in the Internet protocol-based multimedia subsystem network;
determining whether a first identity of the mobile subscriber authenticated in the Internet protocol-based multimedia subsystem network corresponds to a second identity of the mobile subscriber authenticated in the mobile radio network;
sending, if the first and second identities correspond, a confirmation message from the Internet protocol-based multimedia subsystem network to the mobile subscriber; and
exchanging data between the mobile subscriber and the Internet protocol-based multimedia subsystem network using a security protocol protected by a common key derived from the confirmation message for the security protocol.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the key is the confirmation message.

### Claim 3 (depends on 2)

A method according to claim 2, wherein the key is a common secret between the Internet protocol-based multimedia subsystem network and the mobile subscriber.

### Claim 4 (depends on 2)

A method according to claim 2, wherein the key is a password which can be entered by the mobile subscriber.

### Claim 5 (depends on 4)

A method according to claim 4, wherein the confirmation message is a random value.

### Claim 6 (depends on 5)

A method according to claim 5, wherein said authenticating of the mobile subscriber in the Internet protocol-based multimedia subsystem network uses at least one of a session initiation protocol and a hypertext transfer protocol.

### Claim 7 (depends on 6)

A method according to claim 6, wherein the security protocol is hypertext transfer protocol digest.

### Claim 8

A data network, comprising:
a mobile radio network authenticating a mobile subscriber therein to obtain a first identity of the mobile subscriber;
an Internet protocol-based multimedia subsystem network authenticating the mobile subscriber to obtain a second identity of the mobile subscriber, said networks securing data traffic between the mobile subscriber and the Internet protocol-based multimedia subsystem network by determining whether the first and second identities of the mobile subscriber correspond and, if the first and second identities correspond, sending a confirmation message from the Internet protocol-based multimedia subsystem network to the mobile subscriber and exchanging data between the mobile subscriber and the Internet protocol-based multimedia subsystem network using a security protocol protected by a common key derived from the confirmation message for the security protocol.

### Claim 9 (depends on 8)

A data network according to claim 8, wherein the mobile radio network is at least one of a General Packet Radio Service and a Universal Mobile Telecommunication System network.