2-factor Authenication usiing Google Authenticator

Download the OATH-toolkit

$ http://download.savannah.gnu.org/releases/oath-toolkit/
$ tar -zxvf oath-toolkit-1.12.5.tar.gz
$ ./configure
$ make

Assume the the secret key is JBSWY3DPEHPK3PXP. Run the command on linux will give you the code. Google uses 30 seconds time step and 16 chars base32 secret key.

$ ./oathtool --totp -s 30s -b JBSWY3DPEHPK3PXP
431234

Finally, we need to generate the QR code for Google Authenticator

https://dan.hersam.com/tools/gen-qr-code.html

Fire up Google Authenticator or 1Password, scan the QR code on the screen and you are all set.