[gmaslov]

The way I understand master keys work is that the lock has two "breaks" in each pin, instead of just one. So each pin has two positions that allow the lock to open, and you don't know which one belongs to the master key.

I think at least two locks would be required, and depending on how many pins and possible positions there are, more might be needed in case of a collision.

[brianwawok]

I mean a lock comes with 1 key right? If you make a second key that opens it, but shares nothing with the default key - you may have a winner.