thanks, 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 verifie

thanks, 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...