Revision as of 02:56, 17 August 2016 edit BillMGreenblatt (talk \| contribs) 55 edits →Rolling code vs. fixed code RF remote control: that ← Previous edit		Revision as of 00:44, 8 November 2016 edit undo Neloshaneal (talk \| contribs) 1 edit No edit summary Next edit →
Line 24: The Microchip HCS301 was once the most widely used system on garage and gate remote control and receivers. The chip uses the KeeLoq algorithm. The HCS301 KeeLoq system transmits 66 data bits. * 34 bits are not encrypted : a 28-bit serial number, 4 bits of button information, and 2 status bits (repeat and low battery indicators). * 32 bits are encrypted (the rolling code) : 4 bits of button information, 2 bits of OVR (used to extend counter value), 10 bits of DISC (discrimination value; often the low 10 bits of the serial number), and a 16-bit counter.<ref>{{Citation \|last=Microchip \|title=HC301 KeeLoq Code Hopping Encoder \|year=2001 \|id=DS21143B \|publisher=Microchip Technology Inc. \|___location= \|url=http://ww1.microchip.com/downloads/en/devicedoc/21143b.pdf}}[http://a1garage.com/]. Retrieved 2015-08-11.</ref> In a resyncing situation, the encrypted 32 bits are replaced with a 32-bit seed value. == Vulnerabilities ==

Rolling code: Difference between revisions