Air-gapped Signing Mechanism

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If a hardware wallet is offline, then how does it manage to sign a transaction? How does a hardware wallet work?

A hardware wallet is a kind of hardware device to keep the seed phrase in an offline and isolated environment. This means that a hardware wallet cannot access the internet, nor pull data from the blockchain or automatically update the balance.
In order to execute a transaction, a hardware wallet needs a secure way to interact with the external environment so that it can sign and approve a transaction and transfer the signature to the blockchain. Furthermore, users also need a user-friendly interface to view the most updated balance and manage crypto assets.
To realize these purposes, a lot of hardware wallets are connected with special external software for crypto management purposes. Some use desktop applications, some use web clients, and some use mobile Apps.
With the help of external software, a hardware wallet is able to receive an unsigned transaction from the software, sign the transaction, and then transmit the signature to the external software, so that the software can broadcast to the blockchains.
There are different ways to communicate between the hardware wallet and the software end, such as Bluetooth, NFC, USB connection, QRcode, etc. Radio-frequencies and USB connections are often considered not secure enough because they still potentially expose the connection with the hardware wallet to an internet-accessible environment. Air-gapped signing mechanism becomes a new option for a hardware wallet to communicate with the external environment without exposing the seed to any online environment.

What is the Air-gapped Signing Mechanism?

The Air-gapped signing mechanism is a technology to enable crypto transaction signing without using any radio-frequencies or physical connection. This type of signing is usually done through QRcode communication, which uses image recognition technology and thus does not rely on any internet or external signal.

How does SafePal S1 Hardware Wallet apply with Air-gapped signing technology?

Instead of radio-frequencies, antenna, or USB, SafePal S1 Hardware Wallet adopts air-gapped signing mechanism to keep the device 100% offline.
When a SafePal hardware wallet user needs to send crypto from the SafePal S1 Hardware Wallet to others, the user will create an unsigned transaction on the SafePal App first, and transfer the unsigned transaction details to the SafePal S1 device through encrypted QR code. Once the SafePal S1 hardware wallet receives the unsigned transaction, it can sign and approve the transaction in an offline secure environment. After the transaction is signed, the signature can be transferred back to the SafePal App through the encrypted QR code for further broadcasting. The following video shows how to transfer crypto from SafePal S1 wallet to others.

Can I view the balance on the SafePal S1 hardware wallet?

No, you don't need to. The SafePal S1 hardware wallet won't be able to detect the updated balance from the blockchain due to its nature of being completely offline. When you need to view balance of the seed phrase, simply pair your SafePal S1 with the SafePal App to view the balance and manage your assets. Here is a tutorial on how to set up a SafePal S1 in simple steps.

Do I need to send crypto from the SafePal App to the SafePal S1 hardware wallet for cold storage?

No, you don't need to. The SafePal App builds a connection with a SafePal S1 hardware wallet via encrypted QR code communications. Your crypto asset is actually locked on the blockchain, and managed through the SafePal App. A S1 hardware wallet is a tool to 1) keep your mnemonic phrase safely, and 2) approve any outflow transactions. They play different roles apart.
Since the S1 device is 100% offline, the balance won't be automatically synchronized to the S1 hardware wallet. It's not until the S1 device signs an out-flow transfer then it 'knows' the existence of this newly added token. To view the balance of your assets, please kindly use the SafePal App.
Hence you don't have to transfer your asset from SafePal App to the SafePal hardware device.

Can I use only the SafePal S1 hardware wallet without the App?

If you are a long-term holder without any demand for daily transactions, then the answer is yes. You can store your seed phrase in the SafePal S1 and store it in a secure location.
But if you are aiming for daily crypto management such as transactions, receiving funds, DApp access, then a SafePal App is the must way to go for simple and secure crypto management.
See how the App works with the S1 hardware wallet from the FAQ above.