Crypto Concepts & FAQs
Typically, hardware wallets are not responsible for directly querying the blockchain or broadcasting transactions. The networking work is completed by the wallet client or blockchain node on the mobile phone or computer; The hardware device is mainly responsible for protecting the private key, displaying the information to be confirmed, and generating a signature after the user confirms it.
Core differences:Connecting a hardware wallet to an Internet-connected device does not mean that the hardware wallet itself directly accesses the Internet. Just because the device remains offline for signing does not mean that the incoming transaction content is necessarily safe.
What are the responsibilities of the client and the hardware wallet?
Participants | Main responsibilities | Is an Internet connection usually required? |
Mobile or computer client | Query balance and on-chain status, estimate network fees, construct transactions and broadcast results | usually required |
hardware wallet | Receive data to be signed, display key information on the device screen and complete the signature | No. Signing itself does not require an internet connection. |
A typical transaction can be simplified into four steps:
The client obtains the latest on-chain status and constructs the transaction to be signed;
Transaction data is transferred to the hardware wallet;
The user checks the device screen and the device generates a signature after confirmation;
The signature result is returned to the client and broadcast to the blockchain by the networked device.
The client usually needs to be connected to the Internet to obtain the latest information such as balance, Nonce, UTXO or fees. Signing can be done offline, but the transaction still needs to be broadcast by a networked device or node.
Are USB, Bluetooth, NFC and QR codes considered connected?
These methods are mainly used to transfer data between devices and do not automatically mean that the hardware wallet can directly access the Internet:
USB, Bluetooth and NFC:Establish local wired or short-range wireless data channels;
QR code or memory card:No persistent connection is established, but the data to be signed and the signature result will still be delivered;
Wi-Fi, cellular, or internet client:Used to exchange data with remote services or blockchain nodes.
Air-Gap mode can reduce the attack surface posed by a specific connection channel, but the QR code itself can still carry errors or malicious transaction data. UKey Core 26 For detailed procedures, seeHow to connect to UKey Core 26 via QR code (Air-Gap mode) and sign a transaction?.
The dimensions described by "hardware wallet", "cold wallet" and "offline wallet" are not exactly the same. For specific differences, seeAre hardware wallets, cold wallets and offline wallets the same thing?.
What else can you do when your device is offline?
Receive assets:Yes. Payment occurs on the blockchain address and does not require the hardware device to be powered on.
View balance:The network client queries the on-chain information of the public address.
Generate signature:Yes, but the signature result still needs to be broadcast to the network client or node.
Why do offline signatures still need to be checked against the device screen?
Transactions to be signed are usually constructed by networked clients. If the phone, computer, website, or client is tampered with, the address, amount, network, or authorization content passed into the device may be different than the user originally intended. Hardware wallets do not automatically determine whether an address, DApp or smart contract is trustworthy.
Before confirmation, the information actually displayed by the device should be used as an independent verification basis; if it is incomprehensible, incompletely displayed, or inconsistent with the client, the signature should be rejected. See the division of responsibilities and security boundaries of transaction signatures.How does a UKey hardware wallet secure transaction signing?.