php集成动态口令认证

xgnic

            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 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 $lut = array( // Lookup needed for Base32 encoding
  "A" => 0, "B" => 1,
  "C" => 2, "D" => 3,
  "E" => 4, "F" => 5,
  "G" => 6, "H" => 7,
  "I" => 8, "J" => 9,
  "K" => 10, "L" => 11,
  "M" => 12, "N" => 13,
  "O" => 14, "" => 15,
  "Q" => 16, "R" => 17,
  "S" => 18, "T" => 19,
  "U" => 20, "V" => 21,
  "W" => 22, "X" => 23,
  "Y" => 24, "Z" => 25,
  "2" => 26, "3" => 27,
  "4" => 28, "5" => 29,
  "6" => 30, "7" => 31
);
/**
  * Generates a 16 digit secret key in base32 format
  * @return string
  **/
public static function generate_secret_key($length = 16) {
  $b32  = "234567QWERTYUIOPASDFGHJKLZXCVBNM";
  $s  = "";
  for ($i = 0; $i = 8) {
    $j = $j - 8;
    $binary .= chr(($n & (0xFF > $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 || $next > ($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)