John Garcia
Senior HTF Member
This is part of the reason why his One Ring could control all the others, because the programming the Elvish used was supplied by a 3rd party and had a backdoor password that allowed Sauron to hack into their processes and use them for his own compiles.
So it is now, the Nine he has gathered to himself; the Seven also or they are destroyed. The Three are hidden still, but that no longer troubles him. He only needs the One; for he made that Ring himself, and he let a great part of his former power pass into it, so that he could rule all the others. If he recovers it, then he will command them all again, wherever they be, even the Three, and all that has been wrought with them will be laid bare and he will be stronger than ever.
With respect to the Three elven Rings:
The Three, fairest of all, the Elf-Lords hid from him, and his hand never touched or sullied them.