120 lines
3.9 KiB
PHP
120 lines
3.9 KiB
PHP
<?php
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/*
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* Copyright (c) 2011 Le Lag
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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namespace OTPHP {
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/**
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* One Time Password Generator
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*
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* The OTP class allow the generation of one-time
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* password that is described in rfc 4xxx.
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*
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* This is class is meant to be compatible with
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* Google Authenticator.
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*
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* This class was originally ported from the rotp
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* ruby library available at https://github.com/mdp/rotp
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*/
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class OTP {
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/**
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* The base32 encoded secret key
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* @var string
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*/
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public $secret;
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/**
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* The algorithm used for the hmac hash function
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* @var string
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*/
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public $digest;
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/**
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* The number of digits in the one-time password
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* @var integer
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*/
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public $digits;
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/**
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* Constructor for the OTP class
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* @param string $secret the secret key
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* @param array $opt options array can contain the
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* following keys :
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* @param integer digits : the number of digits in the one time password
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* Currently Google Authenticator only support 6. Defaults to 6.
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* @param string digest : the algorithm used for the hmac hash function
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* Google Authenticator only support sha1. Defaults to sha1
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*
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* @return new OTP class.
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*/
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public function __construct($secret, $opt = Array()) {
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$this->digits = isset($opt['digits']) ? $opt['digits'] : 6;
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$this->digest = isset($opt['digest']) ? $opt['digest'] : 'sha1';
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$this->secret = $secret;
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}
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/**
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* Generate a one-time password
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*
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* @param integer $input : number used to seed the hmac hash function.
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* This number is usually a counter (HOTP) or calculated based on the current
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* timestamp (see TOTP class).
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* @return integer the one-time password
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*/
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public function generateOTP($input) {
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$hash = hash_hmac($this->digest, $this->intToBytestring($input), $this->byteSecret());
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foreach(str_split($hash, 2) as $hex) { // stupid PHP has bin2hex but no hex2bin WTF
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$hmac[] = hexdec($hex);
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}
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$offset = $hmac[19] & 0xf;
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$code = ($hmac[$offset+0] & 0x7F) << 24 |
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($hmac[$offset + 1] & 0xFF) << 16 |
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($hmac[$offset + 2] & 0xFF) << 8 |
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($hmac[$offset + 3] & 0xFF);
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return $code % pow(10, $this->digits);
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}
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/**
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* Returns the binary value of the base32 encoded secret
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* @access private
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* This method should be private but was left public for
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* phpunit tests to work.
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* @return binary secret key
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*/
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public function byteSecret() {
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return Base32::decode($this->secret);
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}
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/**
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* Turns an integer in a OATH bytestring
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* @param integer $int
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* @access private
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* @return string bytestring
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*/
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public function intToBytestring($int) {
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$result = Array();
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while($int != 0) {
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$result[] = chr($int & 0xFF);
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$int >>= 8;
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}
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return str_pad(join(array_reverse($result)), 8, "\000", STR_PAD_LEFT);
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}
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}
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}
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