Abstract: The present invention teaches a method and system of encrypting a set of data having a test bit. The method comprises the step of generating a first and a second data string from the set of data. Once generated, the test bit is tested, and should it comprises a first value, the first data string is shifted in a first direction to transfer a carry over bit from a carry over register into the first data string while transferring a first bit of the first data string to said carry over register. This shifting step is followed by the step of shifting the second data string in a second direction to transfer a first bit of the second data string to the carry over register while transferring the carry over bit from the carry over register into the second data string. However, if the test bit comprises a second value, a first logic operation is executed on the first data string with a first number, and a second logic operation is executed on the second data string with a second number.

Abstract: The present invention teaches a method and system for resynchronizing a remote keyless entry receiver having received a new encrypted message transmitted by the transmitter which does not match a previous encrypted message, also transmitted by the transmitter, and stored in memory. The method comprises a first step of transmitting and receiving a first new follow up encrypted message. Subsequently, the received new encrypted message is re-encrypted, and that result is tested against the received first new follow up encrypted message to determine whether there is a match. In the event both match, a second new follow up encrypted message transmitted and received. At this point, the received re-encrypted new encrypted message is re-encrypted a second time, and that result is tested against the received second new follow up encrypted message to determine whether there is a further match.