Before revision: A rolling code (or sometimes called a hopping code) is used in keyless entry systems to prevent replay attacks , where an eavesdropper records the transmission and replays it at a later time to cause the receiver to 'unlock'.
After revision: A rolling code (or sometimes called a hopping code) is used in keyless entry systems to prevent a simple form of replay attack , where an eavesdropper records the transmission and replays it at a later time to cause the receiver to 'unlock'.