Moving 2FA from GAuth

Google Authenticator (GAuth) is a simple and useful app to deal with 2FA, but its simplicity comes at a cost: if you got your device stolen or kind of it, then you lose access to the accounts stored there, unless you have other means to access the accounts, like keywords or authentication through email.

GAuth does not provide easy ways to backup its contents, on the contrary: it makes difficult to export data, but it can be accomplished and this text explains how to do it instead of having to enroll the 2FA for those accounts again.

GAuth

The first thing to do here is to access the GAuth app and extract the accounts enrolled. Start by exporting the accounts through: Options > Transfer Accounts > Export Accounts. GAuth will require the credentials, and after that, select all accounts and click on Next.

As said previously, GAuth does not provide an easy way to migrate accounts, so here it's necessary to use a workaround: using a trusted device, scan the QR code using any trusted app. This QR code has all credentials encoded, so after scanning it, copy the chunk of characters and paste them into a plain text file on your trusted machine --let's call it dump.txt for instance. This chunk will look like this:

otpauth-migration://offline?data=ijEK4ngAIPwDm0BZuqJk6Qvmbi2NpqyAkEgl...

Decoding

Having the encoded accounts, it's needed to decode them to retrieve the secret from each account. Download the extract_otp_secrets script and follow the instructions to install it. The installation is quite easy and as per today, it goes like this:

unzip extract_otp_secrets-master.zip
cd extract_otp_secrets-master
python3 -m venv; source venv/bin/activate
pip install -U -r requirements.txt

With the script ready to run, execute it passing the file with the encoded accounts as parameter:

python src/extract_otp_secrets.py dump.txt

If everything worked as expected, the account list will be shown on the screen, listing for each exported account:

From now, just copy-and-paste the secrets in the new app, so it'll be able to generate the OTPs valid to each service. I highly recommend everyone to test all accounts before removing GAuth. Also, make sure to delete all evidences GAuth data in the machine, like the file with the QR code data and any picture of the QR code itself: remember that if this data leaks, your security will be severely compromised.