OTPHP - A PHP One Time Password Library
This is compatible with Google Authenticator apps available for Android and iPhone, and now in use on GMail
This is a port of the rotp ruby library available at https://github.com/mdp/rotp
Quick overview of using One Time Passwords on your phone
- OTP's involve a shared secret, stored both on the phone and the server
- OTP's can be generated on a phone without internet connectivity(AT&T mode)
- OTP's should always be used as a second factor of authentication(if your phone is lost, you account is still secured with a password)
- Google Authenticator allows you to store multiple OTP secrets and provision those using a QR Code(no more typing in the secret)
clone this repository and include lib/otphp.php in your project.
Time based OTP's
$totp = new \OTPHP\TOTP("base32secret3232"); $totp->now(); // => 492039 // OTP verified for current time $totp->verify(492039); // => true //30s later $totp->verify(492039); // => false
Counter based OTP's
$hotp = new \OTPHP\HOTP("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
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(); // => 'otpauth://firstname.lastname@example.org?secret=JBSWY3DPEHPK3PXP' $hotp->provisioning_uri(); // => 'otpauth://email@example.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.
Scan the following barcode with your phone, using Google Authenticator
Now run the following and compare the output
<?php require_once('otphp/lib/otphp.php'); $totp = new \OTPHP\TOTP("JBSWY3DPEHPK3PXP"); echo "Current OTP: ". $totp->now();
This software is release under MIT licence.