wait I just thought of something, what if you made it so you can only use someones address in which device it was created from or certain devices you allowed. Like if I tried to make a trillion^22 addresses and got someones on my wallet.dat it still would not work even if I had there private key and public address because It was not the device that created the address. Like a picture of satoshi pops up and gives you the finger or something. I mean something needs to be done. I dunno I am a not a coder man guy dude.
Anyone who has access to the private key can autonomously reassign any funds associated with that key. There's no way for the "rightful" owner to block any transactions which did not originate from his/her device. All that is needed is a transaction signed by the private key.
Sidechain solutions like Lightning complicate things, but in general, if someone possesses a private key, they can do whatever they like with the funds. The key itself is the authorization.
The chances of any individual, or even a collaborative effort like LBC, ever finding a
properly generated key (not one which is deliberately weak), are so small as to be effectively 0.00000. In fact if someone were to do the calculations of the probability, 0.00000 (rounded up to 5 decimals) would probably be accurate.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
You would be more likely to lose funds due to some event somewhat within your control, like a hard drive dying, or a trojan stealing your wallet.dat file, rather than someone on the other side of the world brute force cracking your private key.