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 tokenecho("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);*/?>