Hardware wallets are more expensive than you might think, and most hardware wallets connect to USB. This is a security concern for me. So I added the QR code function to the Ethereum Smallet app so that I can use my Android phone as a hardware wallet.
Learn how to do it.
Install the Ethereum Smallet App on your current Android phone. Please refer to this document for detailed installation instructions.
Install Smallet Key Vault on old Android Phone. Once installed, the phone sets airplane mode to block all external connections. While using as a hardware wallet, this phone does not need to be connected to the network, and it is recommended that you do not turn off airplane mode for security reasons.
Open Smallet Key Vault App in your old android phone, and generate new master key or import your master seed.
Once you have entered the master seed, you can create a new Ethereum Public Address using the “Add Account” menu as shown above.
If you touch the added account, QR code is generated and displayed as shown in the above screen. This QR code is the public address of the account you touched.
Now, on another phone with Ethereum Smallet installed, open the menu as shown below and execute the QR code scan to read the QR code displayed in the Smallet Key Vault.
When the QR code is recognized, a new account is registered as shown in the above screen. Verify that the address is the address you chose in the key vault. Accounts read with QR code will display [QR] in the account name.
Now try sending Ethereum.
Enter the address to receive, quantity, gas price, etc. and press the SIGN + TRANSFER button. Then the QR code appears on the screen as above. This time, this QR code is read from the smart phone equipped with Smallet Key Vault using QR code reading menu.
If you read it successfully, it will appear as above. Click “Confirm”. Then the QR code appears again as shown on the right side of the above screen. Rereading this QR code in the Ethereum Smallet App will start the transfer.
The Smallet Key Vault, which stores the private key, can not be hacked using any type of network because all connections are blocked in airplane mode and only the QR code is used to send and receive data between the wallet and the key bolt. The method of using QR code is superior to the existing hardware wallet using USB.
Smallet Key Vault source code can be found here.
