# US 11,443,028 B2 · Digital credential revocation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,443,028 B2 - Document ID: US11443028B2 - Status: Granted - Kind: B2 - Application number: 16/578,198 - Filed: 2019-09-20 - Published: 2020-04-02 - Granted: 2022-09-13 - Earliest claimed: 2018-09-27 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Matthias Lerch; Florian Galdo - Web page: https://patentgrep.com/patent/US11443028B2 ## CPC - G06F 21/45: Structures or tools for the administration of authentication - H04L 63/06: {for supporting key management in a packet data network (cryptographic mechanisms or cryptographic arrangements for key management H04L9/08)} - H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying} - H04L 9/3228: {One-time or temporary data, i.e. information which is sent for every authentication or authorization, e.g. one-time-password, one-time-token or one-time-key} - H04L 63/101: {Access control lists [ACL]} - H04W 12/068: {using credential vaults, e.g. password manager applications or one time password [OTP] applications} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - 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 device implementing a digital credential revocation system includes at least one processor configured to maintain a valid digital credential list, a revocation list, and a synchronization counter value. The at least one processor is configured to transmit a request to synchronize the valid digital credential list with an electronic device, the request including the valid digital credential list and the revocation list. The at least one processor is further configured to, in response to receipt of an updated valid digital credential list from the electronic device: clear the revocation list, replace the valid digital credential list with the updated valid digital credential list, and increment the synchronization counter value, and fulfill a received credential maintenance request when the received credential maintenance request comprises an other synchronization counter value that is greater than or equal to the incremented synchronization counter value, otherwise deny the received credential maintenance request. ## Claims ### Claim 1 A secure device comprising: a memory; and at least one processor configured to: maintain a valid digital credential list, a revocation list, and a synchronization counter value; transmit a request to synchronize the valid digital credential list with an electronic device, the request comprising the valid digital credential list and the revocation list; receive, from the electronic device, an updated valid digital credential list; in response to receipt of the updated valid digital credential list: clear the revocation list, replace the valid digital credential list with the updated valid digital credential list, and increment the synchronization counter value; and fulfill a received credential maintenance request when the received credential maintenance request comprises an other synchronization counter value that is greater than or equal to the incremented synchronization counter value. ### Claim 2 (depends on 1) The secure device of claim 1, wherein the valid digital credential list comprises one or more identifiers of one or more digital credentials that are authorized to access the secure device, and the revocation list comprises one or more identifiers of one or more digital credentials for which access to the secure device has been revoked. ### Claim 3 (depends on 2) The secure device of claim 2, wherein an expiration time is associated with at least one of the one or more identifiers of the one or more digital credentials in the revocation list and the at least one processor is further configured to: remove the at least one of the one or more identifiers of the one or more digital credentials in the revocation list when a current time is equal to or greater than the expiration time. ### Claim 4 (depends on 2) The secure device of claim 2, wherein the at least one processor is further configured to: facilitate provisioning, to the electronic device, a private key for conveying an access right with respect to the secure device. ### Claim 5 (depends on 1) The secure device of claim 1, wherein the at least one processor is further configured to, in one atomic transaction, clear the revocation list, replace the valid digital credential list with the updated valid digital credential list, and increment the synchronization counter value. ### Claim 6 (depends on 1) The secure device of claim 1, wherein the at least one processor is configured to fulfill the received credential maintenance request by adding a digital credential identifier to the valid digital credential list along with an indication of one or more access rights associated with the digital credential identifier. ### Claim 7 (depends on 1) The secure device of claim 1, wherein the at least one processor is configured to fulfill the received credential maintenance request by removing a digital credential identifier from the valid digital credential list and adding the digital credential identifier, or a corresponding identifier, to the revocation list. ### Claim 8 (depends on 1) The secure device of claim 1, wherein the at least one processor is further configured to: receive, prior to transmitting the request to synchronize the valid digital credential list, an other credential maintenance request, the other credential maintenance request comprising a second other synchronization counter value; and fulfill, prior to transmitting the request to synchronize the valid digital credential list, the other credential maintenance request when the second other synchronization counter value is greater than or equal to the incremented synchronization counter value. ### Claim 9 (depends on 1) The secure device of claim 1, wherein the at least one processor is further configured to: receive a request to access the secure device, the request comprising a digital credential identifier; and grant the request when the digital credential identifier is stored in the valid digital credential list and the digital credential identifier, or a corresponding identifier, is not stored in the revocation list. ### Claim 10 (depends on 1) The secure device of claim 1, wherein the at least one processor is configured to receive the updated valid digital credential list directly from the electronic device via a peer-to-peer connection. ### Claim 11 (depends on 1) These secure device of claim 1, wherein the at least one processor is configured to receive the updated valid digital credential list from the electronic device via a server. ### Claim 12 (depends on 1) The secure device of claim 1, wherein the secure device comprises, or is included in, a vehicle. ### Claim 13 A method comprising: receiving a synchronization request from a secure device, the synchronization request comprising a secure device valid credential list and a secure device revocation list; updating a primary valid credential list based at least in part on the secure device revocation list, the updating comprising: removing a first credential identifier from the primary valid credential list when the first credential identifier is included in the secure device revocation list and is included in the primary valid credential list; and adding a second credential identifier to the primary valid credential list when the second credential identifier is included in the secure device valid credential list and is not included in the primary valid credential list; incrementing a synchronization counter value; and providing the updated primary valid credential list to the secure device. ### Claim 14 (depends on 13) The method of claim 13, further comprising: receiving a request to revoke a digital credential that is used by an other device to access the secure device; and transmitting, to the secure device, a revocation request corresponding to the digital credential, wherein the revocation request comprises the synchronization counter value. ### Claim 15 (depends on 14) The method of claim 14, wherein the revocation request is relayed to the secure device via a server. ### Claim 16 (depends on 14) The method of claim 14, wherein an expiration time is associated with the digital credential and the request to revoke the digital credential is received prior to the expiration time. ### Claim 17 (depends on 14) The method of claim 14, further comprising: transmitting an other revocation request to the other device that indicates a subject digital credential; and receiving, responsive to the other revocation request and from the other device, a revocation attestation data item that confirms that the subject digital credential has been removed from the other device. ### Claim 18 (depends on 13) The method of claim 13, further comprising: receiving, by an electronic device, a request to assign, to a digital credential, one or more access rights with respect to the secure device; and providing, by the electronic device to the secure device, an attestation data item that identifies the digital credential along with the synchronization counter value, and an indication of the one or more access rights. ### Claim 19 (depends on 18) The method of claim 18, wherein the attestation data item is signed with a private key of the electronic device. ### Claim 20 A system comprising: an electronic device comprising: a memory configured to store a primary valid credential list comprising one or more credential identifiers, and a primary synchronization counter value; and at least one processor configured to: receive, wirelessly from a secure device, a request to synchronize the primary valid credential list with a secure device valid credential list, wherein the request comprises the secure device valid credential list and a secure device revocation list; update the primary valid credential list by removing a credential identified in the secure device revocation list and by adding a credential identifier included in the secure device valid credential list; and transmit the updated primary valid credential list to the secure device; and the secure device, wherein the secure device is physically disconnected from the electronic device, the secure device comprising: a memory configured to store the secure device valid credential list, the secure device revocation list, and a secure device synchronization counter value; and at least one processor configured to: receive the updated primary valid credential list from the secure device; responsive to receipt of the updated primary valid credential list, and in a single atomic transaction: replace the secure device valid credential list with the updated primary valid credential list, clear the secure device revocation list, and increment the secure device synchronization counter value; and fulfill a received credential maintenance request when the received credential maintenance request includes an other synchronization counter value that is greater than or equal to the secure device synchronization counter value. ### Claim 21 (depends on 13) The method of claim 13, wherein the secure device comprises, or is included in, a vehicle.