ROTP - The Ruby One Time Password Library

Travis

A ruby library for generating one time passwords according to RFC 4226 and the HOTP RFC

This is compatible with Google Authenticator apps available for Android and iPhone, and now in use on GMail

Quick overview of using One Time Passwords on your phone

Dependencies

Installation

gem install rotp

Use

Time based OTP's

totp = ROTP::TOTP.new("base32secret3232")
totp.now # => 492039

# OTP verified for current time
totp.verify(492039) # => true
sleep 30
totp.verify(492039) # => false

Counter based OTP's

hotp = ROTP::HOTP.new("base32secretkey3232")
hotp.at(0) # => 260182
hotp.at(1) # => 55283
hotp.at(1401) # => 316439

# OTP verified with a counter
totp.verify(316439, 1401) # => true
totp.verify(316439, 1402) # => false

Generating a Base32 Secret key

ROTP::Base32.random_base32 # returns a 16 character base32 secret. Compatible with Google Authenticator

Google Authenticator Compatible

The library works with the Google Authenticator iPhone and Android app, and also includes the ability to generate provisioning URI's for use with the QR Code scanner built into the app.

totp.provisioning_uri("alice@google.com") # => 'otpauth://totp/alice@google.com?secret=JBSWY3DPEHPK3PXP'
hotp.provisioning_uri("alice@google.com", 0) # => 'otpauth://hotp/alice@google.com?secret=JBSWY3DPEHPK3PXP&counter=0'

This can then be rendered as a QR Code which can then be scanned and added to the users list of OTP credentials.

Working example

Scan the following barcode with your phone, using Google Authenticator

QR Code for OTP

Now run the following and compare the output

require 'rubygems'
require 'rotp'
totp = ROTP::TOTP.new("JBSWY3DPEHPK3PXP")
p "Current OTP: #{totp.now}"

Testing

bundle install
bundle exec rspec spec/*

Contributors

git shortlog -s -n

    47  Mark Percival
    6  David Vrensk
    1  Guillaume Rose
    1  Micah Gates
    1  Michael Brodhead & Shai Rosenfeld
    1  Nathan Reynolds
    1  Shai Rosenfeld
    1  Shai Rosenfeld & Michael Brodhead

Changelog

1.4.0

1.3.0

License

MIT Licensed

See also:

Python port PYOTP by Nathan Reynolds - https://github.com/nathforge/pyotp
PHP port OTPHP by Le Lag - https://github.com/lelag/otphp