Patent ID: 8855308

Claim:
A wireless device comprising: one or more processors configured to: store a local value of a frame counter, wherein the local value of the frame counter was used to decrypt data in a first message; receive a second message after the first message over a wireless network, the second message including a sequence counter value and data encrypted by a correspondent using a secret key and a new value of the frame counter as input to the encryption, the new value of the frame counter being different from the sequence counter value and the local value of the frame counter and identifying the second message relative to other messages in a stream of messages; determine the new value of the frame counter from the local value of the frame counter and the sequence counter value in the second message; decrypt the second message based on the new value of the frame counter; detect a decryption error based on a loss of synchronization of the frame counter with the correspondent; and; set an error flag based on the detecting of the decryption error, the error flag indicating the loss of synchronization of the frame counter with the correspondent.