Cold bitcoin wallets are supposed to be malware proof. If you have a piece of logic on a machine that never connects to the internet you have no way of stealing

Cold bitcoin wallets are supposed to be malware proof. If you have a piece of logic on a machine that never connects to the internet you have no way of stealing the private keys. Similarly you can't just modify the message because the user can verify the destination address before committing it. This is a method of sending out the private key within a normal looking message that no one else can detect (not even the person doing the offline transition).