Elementary School Language Explanation Offline Signature (Air-gapped Computer)～
🌟 Imagine a "Isolated Castle"
There is a computer (like your Bitcoin wallet computer) that is never connected to the internet, just like living in a castle without doors:
❌ No Wi-Fi connection
❌ No USB drives plugged in
❌ No touching anything from the internet
It only does one thing: securely signs (stamps) transactions, but hackers can’t touch it at all!
✨ How to use it? (Just like passing little notes)
1⃣ Online Computer: Write the transaction (for example, "Send 10 bucks to Xiaohong"), but don’t sign it (equivalent to not stamping it).
2⃣ Use USB drive/QR code: Manually pass the transaction to the offline computer like a little note (for example, scan the QR code).
3⃣ Offline Computer: Safely sign (stamp) in the castle, then manually pass the signed transaction back to the online computer.
4⃣ Online Computer: Send the stamped transaction to the blockchain～
🛡 Why is it safe?
Even if hackers control your online computer, they can’t steal the password of the offline computer (because the offline computer is completely untouched by the network!).
It’s like the emperor's seal placed deep in the palace, and the bad guys can't even touch it～
🌰 A Little Example
You want to transfer Bitcoin:
Phone (online) writes the transfer information → Generates a QR code.
Use another old phone that is always offline to scan the QR code → Securely sign → Generate a new QR code.
The phone then scans the QR code given by the offline phone → Transaction completed!
This method is called Air-gapped, because there is like an air wall between the computer and the network～ Bitcoin hardware wallets (like Coldcard) are designed like this!
