# US 2010/0166184 A1 · Method of handling security configuration in wireless communications system and related communication device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166184 A1 - Document ID: US20100166184A1 - Status: Published application - Kind: A1 - Application number: 12/558,605 - Filed: 2009-09-14 - Published: 2010-07-01 - Earliest claimed: 2008-12-29 - Assignees: HTC Corporation - Inventors: Chih-Hsiang Wu - Web page: https://patentgrep.com/patent/US20100166184A1 ## CPC - H04W 12/041: Key generation or derivation - H04W 12/0431: Key distribution or pre-distribution; Key agreement - H04W 12/106: Packet or message integrity - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method of handling security configuration for a mobile device using a mapped security context in a wireless communication system includes utilizing the mapped security context to derive ciphering and integrity keys when security configuration, indicating a key update based on a cached security context, is received. ## Claims ### Claim 1 A method of handling security configuration for a mobile device using a mapped security context in a wireless communication system, the method comprising: utilizing the mapped security context to derive ciphering and integrity keys when security configuration, indicating a key update based on a cached security context, is received. ### Claim 2 (depends on 1) The method of claim 1, wherein the security configuration is received via an intra-system handover or an inter-system handover. ### Claim 3 (depends on 2) The method of claim 2, wherein the security configuration is a keyChangeIndicator information element. ### Claim 4 (depends on 1) The method of claim 1, wherein the security configuration is a RRCConnectionReestablishment message of a radio resource control re-establishment procedure. ### Claim 5 (depends on 1) The method of claim 1, wherein using the mapped security context to derive the ciphering and integrity keys when the security configuration, indicating the key update based on the cached security context, is received comprises: deriving a mapped intermediate key from the mapped security context when the security configuration is received; deriving a base-station-level key from the mapped intermediate key; and using the base-station-level key to derive the ciphering and integrity keys. ### Claim 6 (depends on 1) The method of claim 1, wherein the ciphering and integrity keys comprise a radio resource control integrity protection key, a radio resource control encryption key, and a user plane encryption key. ### Claim 7 A method of handling security configuration for a mobile device in a wireless communication system, the method comprising: receiving security configuration associated with a key update based on a cashed security context via an inter-system handover; and determining whether to utilize the cashed security context to derive ciphering and integrity keys according to the security configuration. ### Claim 8 (depends on 7) The method of claim 7, wherein determining whether to utilize the cashed security context to derive the ciphering and integrity keys according to the security configuration comprises determining not to utilize the cashed security context to derive the ciphering and integrity keys and regarding that the inter-system handover is invalid when the security configuration is received and indicates that a base-station-level key shall be updated based on the latest available cashed intermediate key. ### Claim 9 (depends on 8) The method of claim 8 further comprising sending a handover failure message after regarding that the inter-system handover is invalid. ### Claim 10 (depends on 8) The method of claim 8, wherein the security configuration is a keyChangeIndicator information element that is set to TRUE. ### Claim 11 (depends on 7) The method of claim 7, wherein determining whether to utilize the cashed security context to derive the ciphering and integrity keys according to the security configuration comprises determining to utilize the cashed security context to derive the ciphering and integrity keys when the security configuration is received and indicates that a base-station-level key shall be updated based on the latest available cashed intermediate key. ### Claim 12 (depends on 11) The method of claim 11 further comprising: deriving a base-station-level key from a cached intermediate key of the cashed security context when determining to utilize the cashed security context to derive the ciphering and integrity keys; and using the base-station-level key to derive the ciphering and integrity keys. ### Claim 13 (depends on 12) The method of claim 12, wherein the security configuration is a keyChangeIndicator information element that is set to TRUE. ### Claim 14 (depends on 7) The method of claim 7, wherein the ciphering and integrity keys comprise a radio resource control integrity protection key, a radio resource control encryption key, and a user plane encryption key. ### Claim 15 A method of handling security configuration for a mobile device in a wireless communication system, the method comprising: determining whether to utilize a currently-used security algorithm associated with a security function to derive at least a security key according to a received handover when the received handover command does not include any security algorithm assigning configuration associated with the security function. ### Claim 16 (depends on 15) The method of claim 15, wherein determining whether to utilize the currently-used security algorithm associated with the security function to derive the security key according to the received handover when the received handover command does not include any security algorithm assigning configuration associated with the security function comprises: determining not to utilize the currently-used security algorithm to derive the security key and regarding that the handover command is invalid when the received handover command is received via a second generation wireless communication system; and determining to utilize the currently-used security algorithm to derive the security key when the received handover command is received via a wireless communication system other than the second generation wireless communication system. ### Claim 17 (depends on 16) The method of claim 16 further comprising sending a handover failure message when determining that the handover command is invalid. ### Claim 18 (depends on 15) The method of claim 15, wherein the security function is integrity protection, and the security key is a radio resource control integrity protection key. ### Claim 19 (depends on 15) The method of claim 15, wherein the security function is ciphering, and the security keys include a radio resource control encryption key and a user plane encryption key. ### Claim 20 (depends on 15) The method of claim 15 further comprising utilizing an security algorithm assigned by security algorithm assigning configuration to derive the security key when the received handover command includes the security algorithm assigning configuration associated with the security function. ### Claim 21 A communication device of a wireless communication system for accurately handling security configuration, the communication device comprising: a computer readable recording medium for storing mapped security context, cached security context, and program code corresponding to a process; and a processor coupled to the computer readable recording medium, for processing the program code to execute the process; wherein the process comprises: utilizing the mapped security context to derive ciphering and integrity keys when the mapped security context is in use and security configuration, indicating a key update based on the cached security context, is received. ### Claim 22 (depends on 21) The communication device of claim 21, wherein the security configuration is received via an intra-system handover or an inter-system handover. ### Claim 23 (depends on 22) The communication device of claim 22, wherein the security configuration is a keyChangeIndicator information element. ### Claim 24 (depends on 21) The communication device of claim 21, wherein the security configuration is a RRCConnectionReestablishment message of a radio resource control re-establishment procedure. ### Claim 25 (depends on 21) The communication device of claim 21, wherein using the mapped security context to derive the ciphering and integrity keys when the security configuration, indicating the key update based on the cached security context, is received comprises: deriving a mapped intermediate key from the mapped security context when the security configuration is received; deriving a base-station-level key from the mapped intermediate key; and using the base-station-level key to derive the ciphering and integrity keys. ### Claim 26 (depends on 21) The communication device of claim 21, wherein the ciphering and integrity keys comprise a radio resource control integrity protection key, a radio resource control encryption key, and a user plane encryption key. ### Claim 27 A communication device of a wireless communication system for accurately handling security configuration, the communication device comprising: a computer readable recording medium for storing cached security context and program code corresponding to a process; and a processor coupled to the computer readable recording medium, for processing the program code to execute the process; wherein the process comprises: receiving security configuration associated with a key update based on the cashed security context via an inter-system handover; and determining whether to utilize the cashed security context to derive ciphering and integrity keys according to the security configuration. ### Claim 28 (depends on 27) The communication device of claim 27, wherein determining whether to utilize the cashed security context to derive the ciphering and integrity keys according to the security configuration comprises determining not to utilize the cashed security context to derive the ciphering and integrity keys and regarding that the inter-system handover is invalid when the security configuration is received and indicates that a base-station-level key shall be updated based on the latest available cashed intermediate key. ### Claim 29 (depends on 28) The communication device of claim 28, wherein the process further comprises sending a handover failure message after regarding that the inter-system handover is invalid. ### Claim 30 (depends on 28) The communication device of claim 28, wherein the security configuration is a keyChangeIndicator information element that is set to TRUE. ### Claim 31 (depends on 27) The communication device of claim 27, wherein determining whether to utilize the cashed security context to derive the ciphering and integrity keys according to the security configuration comprises determining to utilize the cashed security context to derive the ciphering and integrity keys when the security configuration is received and indicates that a base-station-level key shall be updated based on the latest available cashed intermediate key. ### Claim 32 (depends on 31) The communication device of claim 31, wherein the process further comprises: deriving a base-station-level key from a cached intermediate key of the cashed security context when determining to utilize the cashed security context to derive the ciphering and integrity keys; and using the base-station-level key to derive the ciphering and integrity keys. ### Claim 33 (depends on 32) The communication device of claim 32, wherein the security configuration is a keyChangeIndicator information element that is set to TRUE. ### Claim 34 (depends on 27) The communication device of claim 27, wherein the ciphering and integrity keys comprise a radio resource control integrity protection key, a radio resource control encryption key, and a user plane encryption key. ### Claim 35 A communication device of a wireless communication system for accurately handling security configuration, the communication device comprising: a computer readable recording medium for storing program code corresponding to a process; and a processor coupled to the computer readable recording medium, for processing the program code to execute the process; wherein the process comprises: determining whether to utilize a currently-used security algorithm associated with a security function to derive at least a security key according to a received handover when the received handover command does not include any security algorithm assigning configuration associated with the security function. ### Claim 36 (depends on 35) The communication device of claim 35, wherein determining whether to utilize the currently-used security algorithm associated with the security function to derive the security key according to the received handover when the received handover command does not include any security algorithm assigning configuration associated with the security function comprises: determining not to utilize the currently-used security algorithm to derive the security key and regarding that the handover command is invalid when the received handover command is received via a second generation wireless communication system; and determining to utilize the currently-used security algorithm to derive the security key when the received handover command is received via a wireless communication system other than the second generation wireless communication system. ### Claim 37 (depends on 36) The communication device of claim 36, wherein the process further comprises sending a handover failure message when determining that the handover command is invalid. ### Claim 38 (depends on 35) The communication device of claim 35, wherein the security function is integrity protection, and the security key is a radio resource control integrity protection key. ### Claim 39 (depends on 35) The communication device of claim 35, wherein the security function is ciphering, and the security keys include a radio resource control encryption key and a user plane encryption key. ### Claim 40 (depends on 35) The communication device of claim 35, wherein the process further comprises utilizing an security algorithm assigned by security algorithm assigning configuration to derive the security key when the received handover command includes the security algorithm assigning configuration associated with the security function.