A method includes receiving, at an access point, an access request from a first device after an expiration of a first passcode. The access request is encrypted based on the first passcode. The method includes making a determination by the access point before an expiration of a usage time of a first passcode usage list that an identifier of the first device is included in the first passcode usage list. The method also includes, in response to making the determination, generating, at the access point, data representing a second passcode by encrypting the second passcode using the first passcode; and sending the data representing the second passcode from the access point to the first device.