3 ms·
There is a fuse-antifuse pair most likely. Think of it this way: You burn the bits "0001" into some fuse bank, which is mirrored in an anti-fuse bank that now
by Ristovski 8y ago
There is a fuse-antifuse pair most likely.
Think of it this way:
You burn the bits "0001" into some fuse bank, which is mirrored in an anti-fuse bank that now equals "1110".
You can burn the unburned fuses in the normal bank, but can't unburn them in the antifuse bank.
- DoctorOetker 8y agothanks, I actually thought of that, but it seems rather inefficient compared to a single fuse, unblown before writing a key, blown after written key is verified as correctly written, once blown no fuses for this key can be blown... But I don't know if they actually use such a system, or perhaps they simply assume the attackers never get fuseblowing privilege, and perhaps they assume that a key in a blown set of fuses is no longer rewritable...