# US 12,120,250 B2 · Method and system for reduced V2X receiver processing load using certificates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,250 B2 - Document ID: US12120250B2 - Status: Granted - Kind: B2 - Application number: 18/416,148 - Filed: 2024-01-18 - Published: 2024-05-09 - Granted: 2024-10-15 - Earliest claimed: 2018-06-06 - Assignees: BlackBerry Limited - Applicants: BlackBerry Limited - Inventors: Stephen John Barrett; John Octavius Goyo; James Randolph Winter Lepp - Web page: https://patentgrep.com/patent/US12120250B2 ## CPC - H04L 9/3268: {using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]} - H04W 12/10: Integrity - H04L 9/0825: {using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates} - H04L 9/321: {involving a third party or a trusted authority} - H04L 9/3247: {involving digital signatures} - H04L 9/3297: {involving time stamps, e.g. generation of time stamps} - H04L 63/062: {for key distribution, e.g. centrally by trusted party (cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party H04L9/0819)} - H04W 4/40: for vehicles, e.g. vehicle-to-pedestrians [V2P] - H04W 12/108: Source integrity - H04L 63/068: {using time-dependent keys, e.g. periodically changing keys (cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088)} - H04L 67/12: specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks - H04L 2209/84: Vehicles - H04W 4/44: for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H] - 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 A method at a computing device within an Intelligent Transportation System, the method comprising: determining, at the computing device, whether a short-term certificate is available to sign a message; if the short-term certificate is available, signing the message with a private key associated with the short-term certificate; if the short-term certificate is not available, signing the message with a private key associated with a long-term certificate; and sending the message to a recipient. ## Claims ### Claim 1 A method at a computing device installed within a first vehicle in an Intelligent Transportation System, wherein the Intelligent Transportation System is designed to enhance road safety and road efficiency, the method comprising: receiving, at the computing device, a message from a second vehicle; determining that the message is correctly signed with a private key of a certificate for the second vehicle and that a valid Online Certificate Status Protocol (OCSP) response is appended to the message; based on the determining, passing the message to an application layer at the computing device within the first vehicle. ### Claim 2 (depends on 1) The method of claim 1, wherein the certificate is a long-term certificate for the computing device. ### Claim 3 (depends on 1) The method of claim 1, wherein the OCSP response is valid if the OCSP response has a validity period that has not expired. ### Claim 4 (depends on 1) The method of claim 1, wherein the OCSP response is valid if the OCSP response is correctly signed. ### Claim 5 (depends on 1) The method of claim 1, wherein the valid OCSP response provides an indication that the certificate was recently checked against a certificate revocation list and that the certificate does not need to be checked by the computing device. ### Claim 6 (depends on 1) The method of claim 1, wherein the certificate with the appended OCSP response is received with the message. ### Claim 7 (depends on 1) The method of claim 1, further comprising assuming a validity period for the certificate has not expired based on the presence of the valid OSCP response. ### Claim 8 (depends on 1) The method of claim 1, further comprising: checking, prior to the determining, whether the message contains an OCSP response, and when the message contains no OCSP response, performing a CRL check on the message. ### Claim 9 (depends on 1) The method of claim 1, wherein the message is at least one of a European Telecommunications Standards Institute (ETSI) Cooperative Awareness Message (CAM); an ETSI Decentralized Environmental Notification Message (DENM); and a Dedicated Short Range Communications (DSRC)/Wireless Access In Vehicular Environments (WAVE) system Basic Safety Message. ### Claim 10 A computing device within an Intelligent Transportation System, the computing device comprising: a processor; and a communications subsystem, wherein the computing device is installed within a first vehicle and configured to: receive a message from a second vehicle; determine that the message is correctly signed with a private key of a certificate for the second vehicle and that a valid Online Certificate Status Protocol (OCSP) response is appended to the message; based on the determination, pass the message to an application layer at the computing device. ### Claim 11 (depends on 10) The computing device of claim 10, wherein the certificate is a long-term certificate for the computing device. ### Claim 12 (depends on 10) The computing device of claim 10, wherein the OCSP response is valid if the OCSP response has a validity period that has not expired. ### Claim 13 (depends on 10) The computing device of claim 10, wherein the OCSP response is valid if the OCSP response is correctly signed. ### Claim 14 (depends on 10) The computing device of claim 10, wherein the valid OCSP response provides an indication that the certificate was recently checked against a certificate revocation list and that the certificate does not need to be checked by computing device. ### Claim 15 (depends on 10) The computing device of claim 10, wherein the certificate with the appended OCSP response is received with the message. ### Claim 16 (depends on 10) The computing device of claim 10, wherein the computing device is further configured to assume a validity period for the certificate has not expired based on the presence of the valid OSCP response. ### Claim 17 (depends on 10) The computing device of claim 10, wherein the computing device is further configured to: check, prior to the determination, whether the message contains an OCSP response, and when the message contains no OCSP response, perform a CRL check on the message. ### Claim 18 (depends on 10) The computing device of claim 10, wherein the message is at least one of a European Telecommunications Standards Institute (ETSI) Cooperative Awareness Message (CAM); an ETSI Decentralized Environmental Notification Message (DENM); and a Dedicated Short Range Communications (DSRC)/Wireless Access In Vehicular Environments (WAVE) system Basic Safety Message. ### Claim 19 A non-transitory computer readable medium within an Intelligent Transportation System for storing instruction code, which, when executed by a processor of a computing device installed within a first vehicle cause the computing device to: receive a message from a second vehicle; determine that the message is correctly signed with a private key of a certificate for the second vehicle and that a valid Online Certificate Status Protocol (OCSP) response is appended to the message; based on the determination, pass the message to an application layer at the computing device. ### Claim 20 (depends on 19) The non-transitory computer readable medium of claim 19, wherein the certificate is a long-term certificate for the computing device.