php集成动态口令认证


            大多数系统目前均使用的静态密码进行身份认证登录，但由于静态密码容易被窃取，其安全性无法满足安全要求。

动态口令采用一次一密、用过密码作废的方式防止了密码被窃取带来的安全问题。 

动态口令分为HOTP（基于事件计数的动态口令，RFC4226）、TOTP（基于时间计数的动态口令,RFC6238）、OCRA（挑战应答式动态口令,RFC6287）等方式。

本文介绍了集成TOTP方式的动态口令认证的方案，PHP框架采用Thinkphp3.2.3，动态口令生成器使用的是google authtication。

1、为Thinkphp框架添加oath算法类

oath算法封装类oath.php代码如下：





<?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;

 }

 /*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('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 = 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);

*/

?>





由于google的动态口令算法中种子密钥使用了base32编码，因此需要base32算法，base32.php内容如下：





<?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

 * http://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 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=';

 /**

  * 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, ' ');

  if (substr($binaryString, (strlen($binaryString)) - 1) == ' ') {

   $binaryString = substr($binaryString, 0, strlen($binaryString)-1);

  }

  return explode(' ', $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 '';

  }

  // Convert string to binary

  $binaryString = '';

  foreach (str_split($string) as $s) {

   // Return each character as an 8-bit binary string

   $binaryString .= sprintf('%08b', ord($s));

  }

  // Break into 5-bit chunks, then break that into an array

  $binaryArray = self::chunk($binaryString, 5);

  // Pad array to be divisible by 8

  while (count($binaryArray) % 8 !== 0) {

   $binaryArray[] = null;

  }

  $base32String = '';

  // 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 = '/[^A-Z2-7]/';

  $base32String = preg_replace($pattern, '', $base32String);

  if (strlen($base32String) == 0) {

   // Gives an empty string

   return '';

  }

  $base32Array = str_split($base32String);

  $string = '';

  foreach ($base32Array as $str) {

   $char = strpos(self::$alphabet, $str);

   // Ignore the padding character

   if ($char !== 32) {

    $string .= sprintf('%05b', $char);

   }

  }

  while (strlen($string) %8 !== 0) {

   $string = substr($string, 0, strlen($string)-1);

  }

  $binaryArray = self::chunk($string, 8);

  $realString = '';

  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;

 }

}



?>







将这两个文件放到Thinkphp框架的ThinkPHP\Library\Vendor\oath目录下，oath目录是自己创建的。

2、添加数据库字段

用户表添加如下字段: 

auth_type（0-静态密码，1-动态口令） 

seed（种子密钥） 

temp_seed（临时种子密钥） 

last_logintime（上次登录成功时间） 

last_otp（上次使用密码） 

其中auth_type是为了标明用户使用的哪种认证方式，seed为用户的种子密钥，temp_seed为用户未开通前临时保存的一个种子密钥，如果用户开通动态口令认证成功，该字段内容会填到seed字段。last_logintime和last_otp为上次认证成功的时间和动态口令，用于避免用户同一个口令重复使用。

3、代码集成

1）、开通动态口令

在原有系统的修改密码页面，加上认证方式的选择，例如：



如果用户选择动态口令方式，则会生成一张二维码显示在页面，用于用户开通动态口令。为了兼容google authtication，其二维码格式与谷歌一样。生成二维码的方法见我的另一篇《Thinkphp3.2.3整合phpqrcode生成带logo的二维码》 。 

生成密钥二维码代码如下：





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是生成随机字符串函数。$rand=str_replace('=','',$rand)这句代码是因为谷歌手机令牌中base32解码算法并没有填充的‘='号。 



验证用户动态口令的代码如下：





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）、动态口令登录

用户动态口令登录验证的代码：

从数据库读取auth_type,seed,last_otp字段。







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、测试验证

下载google authtication，使用静态密码登录系统，进入修改密码页面。 

打开google authtication，扫描二维码，会显示动态口令。





保存内容，开通动态口令成功！ 

然后你就可以用高大上的动态口令登录系统了!

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持中文源码网。