US Patent 11074033 Access control and validation using sonic tones

Controlled access to a physical area or secured service is managed using sonic tones. A secret key is stored in a user device and in a security system, and then when access is desired, the secret key or a derivative thereof is encoded into a sonic tone which is transmitted. The sonic tone is received and decoded to obtain the encoded binary message, which is then compared to an expected binary message, and if there is a match, access is granted by the security system. In illustrated particular embodiments the secret key is used to generate a one-time password based upon the secret key and a randomizing factor, such as the current time.