Parity Signer is a mobile application that allows any smartphone to act as an air-gapped crypto wallet. This is also known as "cold storage".
You can create Substrate (Polkadot) and Ethereum accounts, sign messages/transactions, and transfer funds to and from these accounts without any sort of connectivity enabled on the device.
You must turn off or even physically remove the smartphone's Wifi, Mobile Network, and Bluetooth to ensure that the mobile phone containing these accounts will not be exposed to any online threat.
Disabling the mobile phone's networking abilities is a requirement for the app to be used as intended
With Parity Signer, you keep your private keys secure and sign transactions easily. Turn your old smartphone into a hardware wallet for Ethereum and Ethereum-like blockchains. All data is transmitted over the air via QR-codes.
Start by taking your old smartphone, restoring it to factory settings, then turn off all wifi and bluetooth by going into airplane mode once and for all.
Use your network-connected laptop or tablet to enter the amount and recipient, then verify and sign with Parity Signer.
Scan the QR code provided by Parity Signer to release your transaction to the blockchain and send your funds.
Any data transfer from or to the app happens using QR code. By doing so, the most sensitive piece of information, the private keys, will never leave the phone. The Parity Signer mobile app can be used to store any Polkadot or Ethereum account, this includes KSM, ETH, ETC as well as Ether from various testnets (Kovan, Ropsten...).
Parity Signer is built to be used offline. The mobile device used to run the app will hold important information that needs to be kept securely stored. It is therefore advised to:
- Get a separate mobile device.
- Make a factory reset.
- Enable full-disk encryption on the device, with a reasonable password (might not be on by default, for example for older Android devices).
- Do not use any kind of biometrics such as fingerprint or face recognition for device decryption/unlocking, as those may be less secure than regular passwords.
- Once the app has been installed, enable airplane mode and make sure to switch off Wifi, Bluetooth or any connection ability of the device.
- Only charge the phone on a power outlet that is never connected to the internet. Only charge the phone with the manufacturer's charging adapter.
- Do not charge the phone on public USB chargers.