Saw this earler, but wasn’t in a place I could reply. Got some serious mulling done as a result. There’s alot of possibilities here, and I’m gonna divide them into two camps.
Camp Funky Variables.
I can think of a bunch of scenarios that fit this. For instance there could be some kind of floating input on the unused pins that triggered a master key event. The eeprom being corupted is another. All of these scenarios share the common theme of an unlikely psuedo random happenstance that caused a triggering event.
Camp Secret Knock
In this camp I put all the scenarios that are based around an unkown combination activating an enrolling process. Could be an on - off cycle bink code, could be something else. The point is there is a repeatable process that got stumbled upon.
At this point we need to totally renounce Camp Funky Variables and all it’s inhabitants. Why? Cause they’re non repeatable within any reasonable time frame. It would take the proverbial million monkeys pounding away for a million years. It’s not that Camp Funky Variables is invalid, it’s just pointless to waste effort on. That lets us concentrate all our effort on what we can solve for, the answers in Camp Secret Knock.
We have some Secret Knock clues.
The power was intermittent, and / or being cycled.
Compgeek was presenting his implant during this process.
Comes from human nature. People tend to repeat what works for them. For example, were Amal to introduce a new implant, better than average odds that it’s name would start with x. If Pilgrimaster builds something, it’ll be measured in mm, and the components will be spaced accordingly. So if you try to guess the distance to the next piece, take an educated guess in a nice round metric number. If I designed it, that would be in decimal inches.
We don’t have any other products from the designer of the xAC, but he did leave us two processes that we can examine. To enroll a new tag, hold the master for 5 seconds, and then present the new tag. To erase all tags, hold the master for 10 seconds. Clearly he uses tag presentation and timing in design work. It’s VERY reasonable to assume any secret knock would as well.
Unfortunately it’s gonna take guess work to figure it out.
Using the clues we have, I’d start by hazarding a guess that the secret knock involves presenting a tag to the reader at power up, and holding it there for a set period of time. 5 seconds perhaps.
Compgeek may be able to narrow the field down if he can be more specific as to what was / was not going on during the time that the master key got re-written / swapped.
1 Was the power cycled while your tag was presented?
2 Was the original Master key in play in any way?
3 Was your implant held on the reader for a period of time? If so, how long?
4 Did you at anytime experience a short circuit?
5 Don’t let all the questions fluster you, but details are gonna be super helpful. Watchya got?