US Patent 11924188 Systems and methods for cryptographic authentication of contactless cards

Example embodiments of systems and methods for data transmission between a contactless card, a client device, and one or more servers are provided. The memory of the contactless card may include one or more applets and a counter. The client device may be in data communication with the contactless card and one or more servers, and the one or more servers may include an expected counter value. The client device may be configured to read the counter from the contactless card and transmit it to the one or more servers. The one or more servers may compare the counter to the expected counter value for synchronization. The contactless card and the one or more servers may resynchronize the counter, via one or more processes, based on one or more reads of the one or more applets. The one or more servers may authenticate the contactless card based on the resynchronization.