Configures a Google Authenticator TOTP in slot 2 on a yubikey for use on linux.

linux-onetime-setup.py

#!/usr/bin/env python

# Ubuntu Installation
# - Install the ubuntu yubico ppa: sudo add-apt-repository ppa:yubico/stable
# - Update your apt cache: sudo apt update
# - Install the package for ykcalresp: sudo apt install yubikey-personalization
# - Copy the secret key below the qr code.
# - Run the gist and enter the secret key when prompted.

import base64
import binascii

def decode_secret(secret):
    secret = secret.replace(' ', '')
    secret = secret.upper()
    secret = secret.encode('ascii')
    secret = base64.b32decode(secret)
    return secret
    
def get_input():
    return raw_input('Google key: ')

def main():
    secret = decode_secret(get_input())
    encoded_key = binascii.hexlify(secret).decode('ascii').ljust(40, '0')
    print('run the following command to update your yubikey')
    print("ykpersonalize -2 -o chal-resp -o chal-hmac -o hmac-lt64 -o chal-btn-trig -a %s") % encoded_key

if __name__ == '__main__':
    main()