How to obviate loosing access when using two-factor-authentication

Question

Sorry if this question is a duplicate. I searched some hours but could not find any satisfying solution for the following problem.

I am using a two-factor-authentication-app (in my case Google Authenticator) for advanced security. This works well.

But I am afraid: what can I do if I lose my smartphone or my smartphone is broken? How can I restore the access to the several websites/services/etc that require two-factor-authentication-app? Is there any "seed" I can backup (and "import" in the two-factor-authentication-app on my new phone) to restore login-access to all sites/services where I am using two-factor-authentication?

Let's think about the following case:

I am using a two-factor-authentication for login to example.com. Now I have not access to my smartphone anymore and can not disable two-factor-authentication for my example.com-account because I can not login and example.com does not provide alternative login-options. I can not see any possibility to login to example.com.

The issue that someone else may get access to my two-factor-authentication-app is not a part of my question because if my smartphone is stolen the thief does not know my regular password.

Answer 1

You can use a TOTP-compliant app that will share your logins across multiple devices, such as Authy or 1Password and store them in the cloud. Of course, that's also a bit less secure, since it gives you another way that your logins can leak. I personally use Authy to share my two-factor logins across four different devices.

Answer 2

Now, after some years, i have found a way to go. For everyone else who has the same question i write it here as possible solution:

Always when we enable 2FA anywhere we copy the qr-code-value. In this qr-code-uri there is always a "secret" key. This is the important part for the backup, but we can simply do a backup of the entire qr-code-uri on a secure place (for example in a password-manager). When the 2fa-device is lost or broke then we simply re-enter the secret-key from the qr-code-uri stored in the password-manager. Obviously it is also possible to use a (offline-)qr-code-generator to recreate the qr-code to be able to simply scan the qr-code like we have done it first time.

Nevertheless thanks to Mike Scott for the alternative solution.