Patent ID: 11895251
Assignee: ASSA ABLOY AB
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. A verifier device of an authentication system, the verifier device comprising:
physical layer circuitry; and
processing circuitry operatively coupled to the physical layer circuitry and configured to:
encode an authentication command for sending to a credential device to authenticate the credential device;
decode a response communication received from the credential device in response to the authentication command, wherein the response communication includes a first random number determined the credential device using a counter value and updating the counter value for each communication session between the verifier device and the credential device;
in response to decoding the response communication that includes the first random number, determining the receiver device keying material using the first random number, a second random number and verifier device keying material specific to the verifier device;
encrypt the first random number, the second random number, and the verifier device keying material for sending to the credential device;
decrypt encrypted information received from the credential device, wherein the encrypted information includes the first random number, the second random number, and the receiver device keying material according to a script included in the verifier device, wherein the receiver device keying material is produced using a static encryption key specific to the credential device and the first random number and includes a third random number predictable by the verifier device; and
calculate a session encryption key using the static encryption key, the verifier device keying material and the receiver device keying material.