Embodiments of the invention provide methods for key fob to control unit verification, retention, and revocation. After an initial pairing between a key fob and a control unit, the devices share a secret operation key (OpKey). For verification, the key fob sends the 8 lowest-order bits of a 128-bit counter and some bits of an AES-128, OpKey encrypted value of the counter to the control unit. For key revocation and retention, the control unit is prompted to enter an OpKey retention and revocation mode. Subsequently, each of the remaining or new key fobs is prompted by the user to send a verification message to the control unit. When the control unit is prompted to exit the OpKey retention and revocation mode, it retains the OpKeys of only the key fobs that sent a valid verification message immediately before entering and exiting the OpKey retention and revocation mode.