A method and an apparatus for decrypting encrypted data transmitted wirelessly by updating a key-table comprises a receiver in wireless communication with a sender. The method includes receiving an encrypted data from the sender; searching a key-table of the receiver for a decryption key corresponding to the encrypted data; if the decryption key is not stored in the key-table, driving the receiver for searching a master list of the receiver for the decryption key and transferring the decryption key from the master list to the key-table to update the key-table; and decrypting the encrypted data through utilizing the decryption key stored in the key-table. The method also includes the option of disabling the sending of an acknowledgement message from the receiver to the sender after having received data from the sender.