A free app for Android, by Quest Owl.

The Authenticator app generates and reads QR codes. You can use it to quickly and conveniently add tokens to your online accounts. It’s also perfect for creating and managing a list of accounts that require extra security, like your main email account, your online bank, and so on.

The app generates QR codes for you, which you can use to add the tokens directly to your online accounts, or to your mobile phone. It’s very easy to use, and you don’t need to have any coding knowledge to use it.

QR codes are a form of barcode, which is a specific type of discrete structure for storing data. They are an efficient, portable way of transferring data and information, and they are easy to use for both humans and machines.