# US 10,028,141 B2 · Method and system for determining that a SIM and a SIP client are co-located in the same mobile equipment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,028,141 B2 - Document ID: US10028141B2 - Status: Granted - Kind: B2 - Application number: 15/118,479 - Filed: 2015-02-10 - Published: 2017-07-20 - Granted: 2018-07-17 - Earliest claimed: 2014-02-12 - Assignees: IPCO Corporation - Applicants: Ipco AS - Inventors: Torbjoern Faller; Rolf Roesok - Web page: https://patentgrep.com/patent/US10028141B2 ## CPC - H04W 12/06: Authentication - H04L 65/1059: End-user terminal functionalities specially adapted for real-time communication - H04L 65/1073: Registration or de-registration - H04L 65/1104: Session initiation protocol [SIP] - H04W 4/60: Subscription-based services using application servers or record carriers, e.g. SIM application toolkits - H04W 8/10: between location register and external networks - H04W 12/04: Key management, e.g. using generic bootstrapping architecture [GBA] - H04W 12/08: Access security - H04W 60/005: {Multiple registrations, e.g. multihoming} - H04W 88/06: adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals - H04L 63/0853: {using an additional device, e.g. smartcard, SIM or a different communication terminal (cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234)} - H04L 2101/654: International mobile subscriber identity [IMSI] numbers - H04W 12/72: Subscriber identity - H04W 84/12: WLAN [Wireless Local Area Networks] - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method and system for determining that a SIM and a SIP client are co-located in the same ME. A SIP server, an SLR, and the ME are communicatively interconnected in the system. The SIM has an IMSI and is arranged in the ME. In the method and system, a security module, SLM-SM, included in SIM, encrypts, using a key, a variable derived from the IMSI, and provides a first password parameter as a result of the encrypting. Further, a SIP client location manager, SLM, included in the ME, receives the ME security code; performs an XOR operation of the ME security code and the identity of the ME, and provides a second password parameter as a result of the XOR operation. The SLR performs a process for SIP client presence and location update for mobile operators MSISDN, including receiving the second password parameter from the SLM via the SIP server, decrypting the second password parameter using the key, performing an XOR-operation of the decrypting result with a seed; comparing the result of the XOR-operation with the IMSI, and upon match, determining that the SIM and the SIP client are co-located in the same ME. ## Claims ### Claim 1 A method for determining that a SIM and a SIP client are co-located in the same mobile equipment, ME, wherein a SIP server, a SIP Location Register, SLR, and the ME are communicatively interconnected, the SIM being arranged in the ME, the SIM having an IMSI, the method comprising the following steps performed by a security module, SLM-SM, included in SIM: encrypting, using a key, a variable derived from the IMSI, providing a first password parameter as a result of the encrypting step; and calculating an ME security code by XOR operation of the password parameter and an identity of the ME; the method further comprising the following steps performed by a SIP client location manager, SLM, included in the ME: receiving the ME security code; performing an XOR operation of the ME security code and the identity of the ME, and providing a second password parameter as a result of the XOR operation; the method further comprising a process, performed by the SLR, for SIP client presence and location update for mobile operators MSISDN, the process including: receiving the second password parameter from the SLM via the SIP server; decrypting the second password parameter using the key; performing an XOR-operation of the decrypting result with a seed; comparing the result of the XOR-operation with the IMSI; and upon match, determining that the SIM and the SIP client are co-located in the same ME. ### Claim 2 (depends on 1) The method according to claim 1, wherein the encrypting step, performed by the SLM security module, includes deriving the variable from the IMSI by an XOR operation of the IMSI with a seed. ### Claim 3 (depends on 1) The method according to claim 1, wherein the variable equals the IMSI. ### Claim 4 (depends on 1) The method according to claim 1, wherein the identity of the ME is an IMEI or is derived from the IMEI. ### Claim 5 (depends on 1) The method according to claim 1, further comprising, by the SLR, receiving a request for sending routing information from a HLR; and initiating an alive request towards the SLM; and determining, based on a response from the SLM, if the ME is available or not available on Wi-Fi. ### Claim 6 (depends on 5) The method according to claim 5, further comprising, by the SLR, if the ME is available on Wi-Fi, sending to the HLR a response including a valid mobile subscriber roaming number. ### Claim 7 A mobile communication system, including: a mobile equipment, ME, a SIP server, a SIP Location Register, SLR, the ME, SIP server and SLR being communicatively interconnected, the ME including a SIM and a SIP client location manager, SLM, the SIM being arranged in the ME, the SIM having an IMSI, the SIM including a security module, SLM Security Module, which is configured to encrypting, using a key, a variable derived from the IMSI, providing a first password parameter as a result of the encrypting step, and calculating an ME security code by an XOR operation of the password parameter and an identity of the ME; the SLM being configured to: receiving the ME security code; performing an XOR-operation of the ME security code and the identity of the ME, and providing a second password parameter as a result of the XOR operation, wherein the SLR is configured to perform a process for SIP client presence and HLR update for mobile operators MSISDN, the process including: receiving the second password parameter from the SLM via the SIP server; decrypting the second password parameter using the key; performing an XOR-operation of the decrypting result with a seed; comparing the result of the XOR-operation with the IMSI; and upon match, determining that the SIM and the SIP client are co-located in the same ME. ### Claim 8 (depends on 7) The system according to claim 7, wherein the SLM security module is configured to, in the encrypting step, deriving the variable from the IMSI by an XOR operation of the IMSI with a seed. ### Claim 9 (depends on 7) The system according to claim 7, wherein the variable equals the IMSI. ### Claim 10 (depends on 7) The system according to claim 7, wherein the identity of the ME is an IMEI or is derived from the IMEI. ### Claim 11 (depends on 7) The system according to claim 7, further comprising a mobile operator core network including a HLR, wherein the SLR is further configured to transmitting a location update message to the HLR, the location update message containing an identity of the SLR as a VLR address, receiving an accept message from the HLR, and upon receipt, sending an access accept message to the SIP server. ### Claim 12 (depends on 11) The system according to claim 11, wherein the SLR is further configured to receiving a request for routing information from the HLR, and upon receipt, transmitting an alive request to the SLM, upon lack of response from the SLM within a predetermined timeout period, indicating that the ME is currently not available on WiFi. ### Claim 13 (depends on 11) The system according to claim 11, wherein the SLR is further configured to receiving a request for routing information from the HLR, and upon receipt, transmitting an alive request to the SLM, and upon receipt of an alive response from the SLM, indicating that the ME is currently available on WiFi. ### Claim 14 (depends on 7) The system according to claim 7, wherein the ME is a portable communication device which is enabled to communicate by mobile communication.