If you properly configure the security of mail / wallets / exchanges, you must install two-factor protection (Google Authenticator). During the configuration process, you need to scan the QR code so that the Authenticator application starts to generate unique 6-digit codes. And you scanned it, you added the key to the application, and everything seems fine.
BUT there is a moment - but what if your phone / tablet breaks, or you lose it, as on the new device to restore the codes Google Authenticator ?
1. You can make screenshots of QR codes when attaching two-factor codes, and hide printouts in the storage room (why not)
2. Use the online version of Google Authenticator, but if you break the laptop / PC, everything will go into oblivion (a bad option)
3. After losing the device, make a million tickets on all exchanges / wallets / mails, and spend months with technical support (very long, and not always efficiently)
4. And you can use special official programs that will help you decrypt the QR code and show you a unique secret key (a set of numbers and letters) that you can enter with the pens on the new device, thereby restoring access to Google Authenticator codes
For Android device ownersApplication: QR Droid
Play Market: https://goo.gl/o8d9BHHow to use: run, scan the QR code when connecting two-factor protection. Next, you will see a text consisting of numbers and letters, eg secret=twwolj564uf7x4se6ft7t2hhfjh1c33v&issuer=Google
When setting up Gmail, all that's in the text after "secret=" and up to the mark "&", and there is your secret key.
When setting up other services: everything in the text after "secret=" and there is your secret key.
For Apple OwnersApplication: QR-Code Reader
App Store: https://goo.gl/5VuLxhHow to use: run, scan the QR code when connecting two-factor protection. Next, you will see a text consisting of numbers and letters, eg secret=twwolj564uf7x4se6ft7t2hhfjh1c33v&issuer=Google
When setting up Gmail, all that's in the text after "secret=" and up to the mark "&", and there is your secret key.
When setting up other services: everything in the text after "secret=" and there is your secret key.
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Keep your keys separate from passwords, always have multiple backups, both on physical media and in print. In this case, in case of force majeure (loss of your electronic equipment), you can quickly restore access to your accounts on different services
P.S. Who helped to understand, you can click on +Merit