For this to work they have to have the correct key in the first place. If I encrypt something with my key and send it down the wire and they intercept it and tr

For this to work they have to have the correct key in the first place. If I encrypt something with my key and send it down the wire and they intercept it and try it on a machine they own they wouldn't be able to decrypt it. This requires them to be hooked to my machine while I am decrypting to get at the key.