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Google TOTP Two-factor Authentication for PHP
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<?php | |
/** | |
* This program is free software: you can redistribute it and/or modify | |
* it under the terms of the GNU General Public License as published by | |
* the Free Software Foundation, either version 3 of the License, or | |
* (at your option) any later version. | |
* | |
* This program is distributed in the hope that it will be useful, | |
* but WITHOUT ANY WARRANTY; without even the implied warranty of | |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
* GNU General Public License for more details. | |
* | |
* You should have received a copy of the GNU General Public License | |
* along with this program. If not, see <http://www.gnu.org/licenses/>. | |
* | |
* PHP Google two-factor authentication module. | |
* | |
* See http://www.idontplaydarts.com/2011/07/google-totp-two-factor-authentication-for-php/ | |
* for more details | |
* | |
* @author Phil | |
**/ | |
class Google2FA { | |
const keyRegeneration = 30; // Interval between key regeneration | |
const otpLength = 6; // Length of the Token generated | |
private static $lut = array( // Lookup needed for Base32 encoding | |
"A" => 0, "B" => 1, | |
"C" => 2, "D" => 3, | |
"E" => 4, "F" => 5, | |
"G" => 6, "H" => 7, | |
"I" => 8, "J" => 9, | |
"K" => 10, "L" => 11, | |
"M" => 12, "N" => 13, | |
"O" => 14, "P" => 15, | |
"Q" => 16, "R" => 17, | |
"S" => 18, "T" => 19, | |
"U" => 20, "V" => 21, | |
"W" => 22, "X" => 23, | |
"Y" => 24, "Z" => 25, | |
"2" => 26, "3" => 27, | |
"4" => 28, "5" => 29, | |
"6" => 30, "7" => 31 | |
); | |
/** | |
* Generates a 16 digit secret key in base32 format | |
* @return string | |
**/ | |
public static function generate_secret_key($length = 16) { | |
$b32 = "234567QWERTYUIOPASDFGHJKLZXCVBNM"; | |
$s = ""; | |
for ($i = 0; $i < $length; $i++) | |
$s .= $b32[rand(0,31)]; | |
return $s; | |
} | |
/** | |
* Returns the current Unix Timestamp devided by the keyRegeneration | |
* period. | |
* @return integer | |
**/ | |
public static function get_timestamp() { | |
return floor(microtime(true)/self::keyRegeneration); | |
} | |
/** | |
* Decodes a base32 string into a binary string. | |
**/ | |
public static function base32_decode($b32) { | |
$b32 = strtoupper($b32); | |
if (!preg_match('/^[ABCDEFGHIJKLMNOPQRSTUVWXYZ234567]+$/', $b32, $match)) | |
throw new Exception('Invalid characters in the base32 string.'); | |
$l = strlen($b32); | |
$n = 0; | |
$j = 0; | |
$binary = ""; | |
for ($i = 0; $i < $l; $i++) { | |
$n = $n << 5; // Move buffer left by 5 to make room | |
$n = $n + self::$lut[$b32[$i]]; // Add value into buffer | |
$j = $j + 5; // Keep track of number of bits in buffer | |
if ($j >= 8) { | |
$j = $j - 8; | |
$binary .= chr(($n & (0xFF << $j)) >> $j); | |
} | |
} | |
return $binary; | |
} | |
/** | |
* Takes the secret key and the timestamp and returns the one time | |
* password. | |
* | |
* @param binary $key - Secret key in binary form. | |
* @param integer $counter - Timestamp as returned by get_timestamp. | |
* @return string | |
**/ | |
public static function oath_hotp($key, $counter) | |
{ | |
if (strlen($key) < 8) | |
throw new Exception('Secret key is too short. Must be at least 16 base 32 characters'); | |
$bin_counter = pack('N*', 0) . pack('N*', $counter); // Counter must be 64-bit int | |
$hash = hash_hmac ('sha1', $bin_counter, $key, true); | |
return str_pad(self::oath_truncate($hash), self::otpLength, '0', STR_PAD_LEFT); | |
} | |
/** | |
* Verifys a user inputted key against the current timestamp. Checks $window | |
* keys either side of the timestamp. | |
* | |
* @param string $b32seed | |
* @param string $key - User specified key | |
* @param integer $window | |
* @param boolean $useTimeStamp | |
* @return boolean | |
**/ | |
public static function verify_key($b32seed, $key, $window = 4, $useTimeStamp = true) { | |
$timeStamp = self::get_timestamp(); | |
if ($useTimeStamp !== true) $timeStamp = (int)$useTimeStamp; | |
$binarySeed = self::base32_decode($b32seed); | |
for ($ts = $timeStamp - $window; $ts <= $timeStamp + $window; $ts++) | |
if (self::oath_hotp($binarySeed, $ts) == $key) | |
return true; | |
return false; | |
} | |
/** | |
* Extracts the OTP from the SHA1 hash. | |
* @param binary $hash | |
* @return integer | |
**/ | |
public static function oath_truncate($hash) | |
{ | |
$offset = ord($hash[19]) & 0xf; | |
return ( | |
((ord($hash[$offset+0]) & 0x7f) << 24 ) | | |
((ord($hash[$offset+1]) & 0xff) << 16 ) | | |
((ord($hash[$offset+2]) & 0xff) << 8 ) | | |
(ord($hash[$offset+3]) & 0xff) | |
) % pow(10, self::otpLength); | |
} | |
} | |
/** | |
* for qr code: otpauth://totp/screenconnect?secret=PEHMPSDNLXIOG65U | |
* for scan qr code in mobile use FreeOTP or Google Authenticator | |
* vhdm.ir | |
*/ | |
$InitalizationKey = "PEHMPSDNLXIOG65U"; // Set the inital key | |
$TimeStamp = Google2FA::get_timestamp(); | |
$secretkey = Google2FA::base32_decode($InitalizationKey); // Decode it into binary | |
$otp = Google2FA::oath_hotp($secretkey, $TimeStamp); // Get current token | |
echo("Init key: $InitalizationKey<br>"); | |
echo("Timestamp: $TimeStamp<br>"); | |
echo("One time password: $otp<br>"); | |
// Use this to verify a key as it allows for some time drift. | |
$result = Google2FA::verify_key($InitalizationKey, "123456"); | |
var_dump($result); | |
?> |
Hi, congratulations for this great work, I want to know if this code can be used by another developer?
hi, you're welcome, yes of course
Ok thats good!
Thank you very very much!!!
Sent from Yahoo Mail for iPhone
On Monday, February 15, 2021, 8:06 AM, Vahid <notifications@github.com> wrote:
@vhdm commented on this gist.
Hi, congratulations for this great work, I want to know if this code can be used by another developer?
hi, you're welcome, yes of course
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Hi, congratulations for this great work, I want to know if this code can be used by another developer?