What would be the safest and most secure setup for a cold wallet? I am now unsure how to transfer from cold wallet to an online address without compromising security.
Would it be possible to transfer BTC from cold wallet to another cold wallet and then send from that secondary cold wallet to an online address? That way my original cold wallet isn't connecting to the internet or being directly exposed?
Years ago I used to use a USB stick between offline and online computer. Then I read somewhere that its not perfectly safe because if the online computer has some worm, it can jump onto the USB key, and then when you connect the USB key to the offline computer it can infect that computer and steal coins. This was far fetched but it made me worry. So I searched for a full proof method.
Basically my old laptop had a crappy camera. However this camera sucked and couldn't read large QR codes. It also had a SD card reader. So what I did was use an old camera from 1995. And I would take photos of the QR code on ONLINE computer, put that SD card into the OFFLINE computer and read it and sign it. That SD card NEVER was connected to the online computer.
Once I signed the transaction, you can take your iPhone, go to Camera and point at QR code and it will display the signed raw transaction that you can later just go to an online block explorer and push it.
This way there is an "AIR GAP". This is probably even safer than hardware wallets however its a ton of work.