PHP integrated dynamic password authentication (recommended)

This article mainly introduces PHP integrated dynamic password authentication in detail. Dynamic passwords use one-time passwords and invalidate used passwords to improve security performance. Interested friends can refer to it

Most systems currently use static passwords for identity authentication login, but because static passwords are easy to be stolen, their security cannot meet security requirements.

Dynamic passwords use a one-time password and invalidate used passwords to prevent security issues caused by password theft.
Dynamic passwords are divided into HOTP (dynamic passwords based on event counting, RFC4226), TOTP (dynamic passwords based on time counting, RFC6238), OCRA (challenge-response dynamic passwords, RFC6287) and other methods.

This article introduces the solution of dynamic password authentication integrating TOTP method. The PHP framework uses Thinkphp3.2.3, and the dynamic password generator uses google authtication.

1. Add oath algorithm class to Thinkphp framework

oath algorithm encapsulation class oath.php code is as follows:

<?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(&#39;/^[ABCDEFGHIJKLMNOPQRSTUVWXYZ234567]+$/&#39;, $b32, $match))
   throw new Exception(&#39;Invalid characters in the base32 string.&#39;);

  $l  = strlen($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 $binary;
 }
 /*by tang*/  
 public static function base32_encode($data, $length){
  $basestr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
  $count = 0;
  if ($length > 0) {
   $buffer = $data[0];
   $next = 1;
   $bitsLeft = 8;

   while (($bitsLeft > 0 || $next < $length)) {
    if ($bitsLeft < 5) {
    if ($next < $length) {
     $buffer <<= 8;
     $buffer |= $data[$next++] & 0xFF;
     $bitsLeft += 8;
    } else {
     $pad = 5 - $bitsLeft;
     $buffer <<= $pad;
     $bitsLeft += $pad;
    }
    }
    $index = 0x1F & ($buffer >> ($bitsLeft - 5));
    $bitsLeft -= 5;
    $result .= $basestr[$index];
    $count++;
   }
   }
   return $result;  
 }
 /**
  * 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(&#39;Secret key is too short. Must be at least 16 base 32 characters&#39;);

  $bin_counter = pack(&#39;N*&#39;, 0) . pack(&#39;N*&#39;, $counter);  // Counter must be 64-bit int
  $hash  = hash_hmac (&#39;sha1&#39;, $bin_counter, $key, true);

  return str_pad(self::oath_truncate($hash), self::otpLength, &#39;0&#39;, 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 = 5, $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);
 }


}
/*
$InitalizationKey = "LFLFMU2SGVCUIUCZKBMEKRKLIQ";     // 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\n");
echo("Timestamp: $TimeStamp\n");
echo("One time password: $otp\n");

// Use this to verify a key as it allows for some time drift.

$result = Google2FA::verify_key($InitalizationKey, "123456");

var_dump($result);
*/
?>

Due to Google’s dynamic password algorithm The medium seed key uses base32 encoding, so the base32 algorithm is required. The content of base32.php is as follows:

<?php
//namespace Base32;
/**
 * Base32 encoder and decoder
 *
 * Last update: 2012-06-20
 *
 * RFC 4648 compliant
 * @link http://www.ietf.org/rfc/rfc4648.txt
 *
 * Some groundwork based on this class
 * https://github.com/NTICompass/PHP-Base32
 *
 * @author Christian Riesen <chris.riesen@gmail.com>
 * @link http://christianriesen.com
 * @license MIT License see LICENSE file
 */
class Base32
{
 /**
  * Alphabet for encoding and decoding base32
  *
  * @var array
  */
 private static $alphabet = &#39;ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=&#39;;
 /**
  * Creates an array from a binary string into a given chunk size
  *
  * @param string $binaryString String to chunk
  * @param integer $bits Number of bits per chunk
  * @return array
  */
 private static function chunk($binaryString, $bits)
 {
  $binaryString = chunk_split($binaryString, $bits, &#39; &#39;);
  if (substr($binaryString, (strlen($binaryString)) - 1) == &#39; &#39;) {
   $binaryString = substr($binaryString, 0, strlen($binaryString)-1);
  }
  return explode(&#39; &#39;, $binaryString);
 }
 /**
  * Encodes into base32
  *
  * @param string $string Clear text string
  * @return string Base32 encoded string
  */
 public static function encode($string)
 {
  if (strlen($string) == 0) {
   // Gives an empty string
   return &#39;&#39;;
  }
  // Convert string to binary
  $binaryString = &#39;&#39;;
  foreach (str_split($string) as $s) {
   // Return each character as an 8-bit binary string
   $binaryString .= sprintf(&#39;%08b&#39;, ord($s));
  }
  // Break into 5-bit chunks, then break that into an array
  $binaryArray = self::chunk($binaryString, 5);
  // Pad array to be pisible by 8
  while (count($binaryArray) % 8 !== 0) {
   $binaryArray[] = null;
  }
  $base32String = &#39;&#39;;
  // Encode in base32
  foreach ($binaryArray as $bin) {
   $char = 32;
   if (!is_null($bin)) {
    // Pad the binary strings
    $bin = str_pad($bin, 5, 0, STR_PAD_RIGHT);
    $char = bindec($bin);
   }
   // Base32 character
   $base32String .= self::$alphabet[$char];
  }
  return $base32String;
 }
 /**
  * Decodes base32
  *
  * @param string $base32String Base32 encoded string
  * @return string Clear text string
  */
 public static function decode($base32String)
 {
  // Only work in upper cases
  $base32String = strtoupper($base32String);
  // Remove anything that is not base32 alphabet
  $pattern = &#39;/[^A-Z2-7]/&#39;;
  $base32String = preg_replace($pattern, &#39;&#39;, $base32String);
  if (strlen($base32String) == 0) {
   // Gives an empty string
   return &#39;&#39;;
  }
  $base32Array = str_split($base32String);
  $string = &#39;&#39;;
  foreach ($base32Array as $str) {
   $char = strpos(self::$alphabet, $str);
   // Ignore the padding character
   if ($char !== 32) {
    $string .= sprintf(&#39;%05b&#39;, $char);
   }
  }
  while (strlen($string) %8 !== 0) {
   $string = substr($string, 0, strlen($string)-1);
  }
  $binaryArray = self::chunk($string, 8);
  $realString = &#39;&#39;;
  foreach ($binaryArray as $bin) {
   // Pad each value to 8 bits
   $bin = str_pad($bin, 8, 0, STR_PAD_RIGHT);
   // Convert binary strings to ASCII
   $realString .= chr(bindec($bin));
  }
  return $realString;
 }
}

?>

Put these two files into the ThinkPHP\Library\Vendor\oath directory of the Thinkphp framework. The oath directory is Created by myself.

2. Add database fields

Add the following fields to the user table:
auth_type (0-static password, 1-dynamic password)
seed (seed) Key)
temp_seed (temporary seed key)
last_logintime (last successful login time)
last_otp (last used password)
where auth_type is to indicate which authentication method the user uses, seed is the user's seed key, and temp_seed is a seed key temporarily saved before the user activates it. If the user successfully activates dynamic password authentication, the content of this field will be filled in the seed field. last_logintime and last_otp are the time and dynamic password of the last successful authentication, which are used to prevent users from reusing the same password.

3. Code integration

1), open dynamic password

in the original system Change the password page and add the selection of authentication method, for example:

# If the user selects the dynamic password method, a QR code will be generated and displayed on the page for the user to activate the dynamic password Password. In order to be compatible with Google authentication, its QR code format is the same as Google's. For the method of generating QR codes, see my other article "Thinkphp3.2.3 integrates phpqrcode to generate QR codes with logo".
The code to generate the key QR code is as follows:

public function qrcode()
 { 
  Vendor('oath.base32');
  $base32 = new \Base32();
  $rand = random(16);//生成随机种子
  $rand = $base32->encode($rand);
  $rand=str_replace('=','',$rand);//去除填充的‘='

  $errorCorrectionLevel =intval(3) ;//容错级别 
  $matrixPointSize = intval(8);//生成图片大小

  //生成二维码图片 
  Vendor('phpqrcode.phpqrcode');
  $object = new \QRcode();
  $text = sprintf("otpauth://totp/%s?secret=%s", $user, $rand);
  $object->png($text, false, $errorCorrectionLevel, $matrixPointSize, 2);

  生成的种子$rand保存到数据库的temp_seed字段
 }

random is a function that generates a random string. The code $rand=str_replace('=','',$rand) is because the base32 decoding algorithm in Google Mobile Token does not fill the '=' sign.

The code to verify user dynamic password is as follows:

从数据库读取temp_seed
Vendor('oath.oath');
$object = new \Google2FA();
if($object->verify_key($temp_seed, $otp)){
 验证成功，将数据库更新seed为temp_seed，auth_type为1，last_otp为otp
}

2), dynamic password login

User dynamic password login verification Code:

Read the auth_type, seed, last_otp fields from the database.

if($auth_type==1){//动态口令
 //防止重复认证    
 if($lat_otp == $otp) {
  动态口令重复使用返回    
 }
 Vendor('oath.oath');
 $object = new \Google2FA();
 if(!$object->verify_key($seed, $otp))
 {
  动态口令不正确
 }
 else
 {
  登录成功，将数据库更新last_otp为$otp,last_logintime为time()
 }    
}

4. Test verification

Download google authtication, use a static password to log in to the system, and enter the password change page.
Open google authentication, scan the QR code, and the dynamic password will be displayed.

Save the content and activate the dynamic password successfully!
Then you can use your dynamic password to log in to the system!

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