gauth: replace Google Authenticator

Installation

With a Go environment already set up, it should be as easy as go get github.com/pcarrier/gauth.

Eg, with GOPATH=$HOME/go, it will create a binary $HOME/go/bin/gauth.

Usage

• In web interfaces, pretend you can't read QR codes, get a secret like hret 3ij7 kaj4 2jzg instead.

• Store one secret per line in ~/.config/gauth.csv, in the format name:secret. For example:

    AWS:   ABCDEFGHIJKLMNOPQRSTUVWXYZ234567ABCDEFGHIJKLMNOPQRSTUVWXYZ234567
    Airbnb:abcd efgh ijkl mnop
    Google:a2b3c4d5e6f7g8h9
    Github:234567qrstuvwxyz
  

• Restrict access to your user:

    $ chmod 600 ~/.config/gauth.csv
  

• Run gauth. The progress bar indicates how far the next change is.

    $ gauth
               prev   curr   next
    AWS        315306 135387 483601
    Airbnb     563728 339206 904549
    Google     453564 477615 356846
    Github     911264 548790 784099
    [=======                      ]
  

• gauth is convenient to use in watch.

    $ watch -n1 gauth
  

• Remember to keep your system clock synchronized and to lock your computer when brewing your tea!

Encryption

gauth supports password-based encryption of gauth.csv. To encrypt, use:

    $ openssl enc -aes-128-cbc -md sha256 -in gauth.csv -out ~/.config/gauth.csv
    enter aes-128-cbc encryption password:
    Verifying - enter aes-128-cbc encryption password:

gauth will then prompt you for that password on every run:

    $ gauth
    Encryption password: 
               prev   curr   next
    LastPass   915200 479333 408710

Note that this encryption mechanism is far from ideal from a pure security standpoint. Please read OpenSSL's notes on the subject.

Compatibility

Tested with:

• Airbnb
• Apple
• AWS
• DreamHost
• Dropbox
• Evernote
• Facebook
• Gandi
• Github
• Google
• LastPass
• Linode
• Microsoft
• Okta (reported by Bryan Baldwin)
• WP.com
• bittrex.com
• poloniex.com

Please report further results to pierre@gcarrier.fr.

Rooted Android?

If your Android phone is rooted, it's easy to "back up" your secrets from an adb shell into gauth.

# sqlite3 /data/data/com.google.android.apps.authenticator2/databases/database \
          'select email,secret from accounts'

Really, does this make sense?

At least to me, it does. My laptop features encrypted storage, a stronger authentication mechanism, and I take good care of its physical integrity.

My phone also runs arbitrary apps, is constantly connected to the Internet, gets forgotten on tables.

Thanks to the convenience of a command line utility, my usage of 2-factor authentication went from 3 to 10 services over a few days.

Clearly a win for security.