| 1 |  |  | <?php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 2 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 3 |  |  | namespace Del\Auth; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 4 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 5 |  |  | use Exception; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 6 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 7 |  |  | class GoogleAuthenticator | 
            
                                                                                                            
                            
            
                                    
            
            
                | 8 |  |  | { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 9 |  |  |     protected $_codeLength = 6; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 10 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 11 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 12 |  |  |      * Create new secret. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 13 |  |  |      * 16 characters, randomly chosen from the allowed base32 characters. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 14 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 15 |  |  |      * @param int $secretLength | 
            
                                                                                                            
                            
            
                                    
            
            
                | 16 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 17 |  |  |      * @return string | 
            
                                                                                                            
                            
            
                                    
            
            
                | 18 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 19 |  |  |     public function createSecret($secretLength = 16) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 20 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 21 |  |  |         $validChars = $this->_getBase32LookupTable(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 22 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 23 |  |  |         // Valid secret lengths are 80 to 640 bits | 
            
                                                                                                            
                            
            
                                    
            
            
                | 24 |  |  |         if ($secretLength < 16 || $secretLength > 128) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 25 |  |  |             throw new Exception('Bad secret length'); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 26 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 27 |  |  |         $secret = ''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 28 |  |  |         $rnd = false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 29 |  |  |         if (function_exists('random_bytes')) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 30 |  |  |             $rnd = random_bytes($secretLength); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 31 |  |  |         } elseif (function_exists('mcrypt_create_iv')) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 32 |  |  |             $rnd = mcrypt_create_iv($secretLength, MCRYPT_DEV_URANDOM); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 33 |  |  |         } elseif (function_exists('openssl_random_pseudo_bytes')) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 34 |  |  |             $rnd = openssl_random_pseudo_bytes($secretLength, $cryptoStrong); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 35 |  |  |             if (!$cryptoStrong) { | 
                            
                    |  |  |  | 
                                                                                        
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                | 36 |  |  |                 $rnd = false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 37 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 38 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 39 |  |  |         if ($rnd !== false) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 40 |  |  |             for ($i = 0; $i < $secretLength; ++$i) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 41 |  |  |                 $secret .= $validChars[ord($rnd[$i]) & 31]; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 42 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 43 |  |  |         } else { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 44 |  |  |             throw new Exception('No source of secure random'); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 45 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 46 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 47 |  |  |         return $secret; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 48 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 49 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 50 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 51 |  |  |      * Calculate the code, with given secret and point in time. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 52 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 53 |  |  |      * @param string   $secret | 
            
                                                                                                            
                            
            
                                    
            
            
                | 54 |  |  |      * @param int|null $timeSlice | 
            
                                                                                                            
                            
            
                                    
            
            
                | 55 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 56 |  |  |      * @return string | 
            
                                                                                                            
                            
            
                                    
            
            
                | 57 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 58 |  |  |     public function getCode($secret, $timeSlice = null) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 59 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 60 |  |  |         if ($timeSlice === null) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 61 |  |  |             $timeSlice = floor(time() / 30); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 62 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 63 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 64 |  |  |         $secretkey = $this->_base32Decode($secret); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 65 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 66 |  |  |         // Pack time into binary string | 
            
                                                                                                            
                            
            
                                    
            
            
                | 67 |  |  |         $time = chr(0).chr(0).chr(0).chr(0).pack('N*', $timeSlice); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 68 |  |  |         // Hash it with users secret key | 
            
                                                                                                            
                            
            
                                    
            
            
                | 69 |  |  |         $hm = hash_hmac('SHA1', $time, $secretkey, true); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 70 |  |  |         // Use last nipple of result as index/offset | 
            
                                                                                                            
                            
            
                                    
            
            
                | 71 |  |  |         $offset = ord(substr($hm, -1)) & 0x0F; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 72 |  |  |         // grab 4 bytes of the result | 
            
                                                                                                            
                            
            
                                    
            
            
                | 73 |  |  |         $hashpart = substr($hm, $offset, 4); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 74 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 75 |  |  |         // Unpak binary value | 
            
                                                                                                            
                            
            
                                    
            
            
                | 76 |  |  |         $value = unpack('N', $hashpart); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 77 |  |  |         $value = $value[1]; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 78 |  |  |         // Only 32 bits | 
            
                                                                                                            
                            
            
                                    
            
            
                | 79 |  |  |         $value = $value & 0x7FFFFFFF; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 80 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 81 |  |  |         $modulo = pow(10, $this->_codeLength); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 82 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 83 |  |  |         return str_pad($value % $modulo, $this->_codeLength, '0', STR_PAD_LEFT); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 84 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 85 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 86 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 87 |  |  |      * Get QR-Code URL for image, from google charts. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 88 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 89 |  |  |      * @param string $name | 
            
                                                                                                            
                            
            
                                    
            
            
                | 90 |  |  |      * @param string $secret | 
            
                                                                                                            
                            
            
                                    
            
            
                | 91 |  |  |      * @param string $title | 
            
                                                                                                            
                            
            
                                    
            
            
                | 92 |  |  |      * @param array  $params | 
            
                                                                                                            
                            
            
                                    
            
            
                | 93 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 94 |  |  |      * @return string | 
            
                                                                                                            
                            
            
                                    
            
            
                | 95 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 96 |  |  |     public function getQRCodeGoogleUrl($name, $secret, $title = null, $params = array()) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 97 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 98 |  |  |         $width = !empty($params['width']) && (int) $params['width'] > 0 ? (int) $params['width'] : 200; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 99 |  |  |         $height = !empty($params['height']) && (int) $params['height'] > 0 ? (int) $params['height'] : 200; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 100 |  |  |         $level = !empty($params['level']) && array_search($params['level'], array('L', 'M', 'Q', 'H')) !== false ? $params['level'] : 'M'; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 101 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 102 |  |  |         $urlencoded = urlencode('otpauth://totp/'.$name.'?secret='.$secret.''); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 103 |  |  |         if (isset($title)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 104 |  |  |             $urlencoded .= urlencode('&issuer='.urlencode($title)); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 105 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 106 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 107 |  |  |         return 'https://chart.googleapis.com/chart?chs='.$width.'x'.$height.'&chld='.$level.'|0&cht=qr&chl='.$urlencoded.''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 108 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 109 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 110 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 111 |  |  |      * Check if the code is correct. This will accept codes starting from $discrepancy*30sec ago to $discrepancy*30sec from now. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 112 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 113 |  |  |      * @param string   $secret | 
            
                                                                                                            
                            
            
                                    
            
            
                | 114 |  |  |      * @param string   $code | 
            
                                                                                                            
                            
            
                                    
            
            
                | 115 |  |  |      * @param int      $discrepancy      This is the allowed time drift in 30 second units (8 means 4 minutes before or after) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 116 |  |  |      * @param int|null $currentTimeSlice time slice if we want use other that time() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 117 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 118 |  |  |      * @return bool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 119 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 120 |  |  |     public function verifyCode($secret, $code, $discrepancy = 1, $currentTimeSlice = null) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 121 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 122 |  |  |         if ($currentTimeSlice === null) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 123 |  |  |             $currentTimeSlice = floor(time() / 30); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 124 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 125 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 126 |  |  |         if (strlen($code) != 6) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 127 |  |  |             return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 128 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 129 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 130 |  |  |         for ($i = -$discrepancy; $i <= $discrepancy; ++$i) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 131 |  |  |             $calculatedCode = $this->getCode($secret, $currentTimeSlice + $i); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 132 |  |  |             if ($this->timingSafeEquals($calculatedCode, $code)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 133 |  |  |                 return true; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 134 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 135 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 136 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 137 |  |  |         return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 138 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 139 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 140 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 141 |  |  |      * Set the code length, should be >=6. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 142 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 143 |  |  |      * @param int $length | 
            
                                                                                                            
                            
            
                                    
            
            
                | 144 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 145 |  |  |      * @return PHPGangsta_GoogleAuthenticator | 
            
                                                                                                            
                            
            
                                    
            
            
                | 146 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 147 |  |  |     public function setCodeLength($length) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 148 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 149 |  |  |         $this->_codeLength = $length; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 150 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 151 |  |  |         return $this; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 152 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 153 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 154 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 155 |  |  |      * Helper class to decode base32. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 156 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 157 |  |  |      * @param $secret | 
            
                                                                                                            
                            
            
                                    
            
            
                | 158 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 159 |  |  |      * @return bool|string | 
            
                                                                                                            
                            
            
                                    
            
            
                | 160 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 161 |  |  |     protected function _base32Decode($secret) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 162 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 163 |  |  |         if (empty($secret)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 164 |  |  |             return ''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 165 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 166 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 167 |  |  |         $base32chars = $this->_getBase32LookupTable(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 168 |  |  |         $base32charsFlipped = array_flip($base32chars); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 169 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 170 |  |  |         $paddingCharCount = substr_count($secret, $base32chars[32]); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 171 |  |  |         $allowedValues = array(6, 4, 3, 1, 0); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 172 |  |  |         if (!in_array($paddingCharCount, $allowedValues)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 173 |  |  |             return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 174 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 175 |  |  |         for ($i = 0; $i < 4; ++$i) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 176 |  |  |             if ($paddingCharCount == $allowedValues[$i] && | 
            
                                                                                                            
                            
            
                                    
            
            
                | 177 |  |  |                 substr($secret, -($allowedValues[$i])) != str_repeat($base32chars[32], $allowedValues[$i])) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 178 |  |  |                 return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 179 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 180 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 181 |  |  |         $secret = str_replace('=', '', $secret); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 182 |  |  |         $secret = str_split($secret); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 183 |  |  |         $binaryString = ''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 184 |  |  |         for ($i = 0; $i < count($secret); $i = $i + 8) { | 
                            
                    |  |  |  | 
                                                                                        
                                                                                     | 
            
                                                                                                            
                            
            
                                    
            
            
                | 185 |  |  |             $x = ''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 186 |  |  |             if (!in_array($secret[$i], $base32chars)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 187 |  |  |                 return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 188 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 189 |  |  |             for ($j = 0; $j < 8; ++$j) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 190 |  |  |                 $x .= str_pad(base_convert(@$base32charsFlipped[@$secret[$i + $j]], 10, 2), 5, '0', STR_PAD_LEFT); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 191 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 192 |  |  |             $eightBits = str_split($x, 8); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 193 |  |  |             for ($z = 0; $z < count($eightBits); ++$z) { | 
                            
                    |  |  |  | 
                                                                                        
                                                                                     | 
            
                                                                                                            
                            
            
                                    
            
            
                | 194 |  |  |                 $binaryString .= (($y = chr(base_convert($eightBits[$z], 2, 10))) || ord($y) == 48) ? $y : ''; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 195 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 196 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 197 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 198 |  |  |         return $binaryString; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 199 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 200 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 201 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 202 |  |  |      * Get array with all 32 characters for decoding from/encoding to base32. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 203 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 204 |  |  |      * @return array | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 205 |  |  |      */ | 
            
                                                                        
                            
            
                                    
            
            
                | 206 |  |  |     protected function _getBase32LookupTable() | 
            
                                                                        
                            
            
                                    
            
            
                | 207 |  |  |     { | 
            
                                                                        
                            
            
                                    
            
            
                | 208 |  |  |         return array( | 
            
                                                                        
                            
            
                                    
            
            
                | 209 |  |  |             'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', //  7 | 
            
                                                                        
                            
            
                                    
            
            
                | 210 |  |  |             'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 15 | 
            
                                                                        
                            
            
                                    
            
            
                | 211 |  |  |             'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 23 | 
            
                                                                        
                            
            
                                    
            
            
                | 212 |  |  |             'Y', 'Z', '2', '3', '4', '5', '6', '7', // 31 | 
            
                                                                        
                            
            
                                    
            
            
                | 213 |  |  |             '=',  // padding char | 
            
                                                                        
                            
            
                                    
            
            
                | 214 |  |  |         ); | 
            
                                                                        
                            
            
                                    
            
            
                | 215 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 216 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 217 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 218 |  |  |      * A timing safe equals comparison | 
            
                                                                                                            
                            
            
                                    
            
            
                | 219 |  |  |      * more info here: http://blog.ircmaxell.com/2014/11/its-all-about-time.html. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 220 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 221 |  |  |      * @param string $safeString The internal (safe) value to be checked | 
            
                                                                                                            
                            
            
                                    
            
            
                | 222 |  |  |      * @param string $userString The user submitted (unsafe) value | 
            
                                                                                                            
                            
            
                                    
            
            
                | 223 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 224 |  |  |      * @return bool True if the two strings are identical | 
            
                                                                                                            
                            
            
                                    
            
            
                | 225 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 226 |  |  |     private function timingSafeEquals($safeString, $userString) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 227 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 228 |  |  |         if (function_exists('hash_equals')) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 229 |  |  |             return hash_equals($safeString, $userString); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 230 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 231 |  |  |         $safeLen = strlen($safeString); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 232 |  |  |         $userLen = strlen($userString); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 233 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 234 |  |  |         if ($userLen != $safeLen) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 235 |  |  |             return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 236 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 237 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 238 |  |  |         $result = 0; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 239 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 240 |  |  |         for ($i = 0; $i < $userLen; ++$i) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 241 |  |  |             $result |= (ord($safeString[$i]) ^ ord($userString[$i])); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 242 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 243 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 244 |  |  |         // They are only identical strings if $result is exactly 0... | 
            
                                                                                                            
                            
            
                                    
            
            
                | 245 |  |  |         return $result === 0; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 246 |  |  |     } | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 247 |  |  | } | 
            
                                                        
            
                                    
            
            
                | 248 |  |  |  | 
            
                        
If an expression can have both
false, andnullas possible values. It is generally a good practice to always use strict comparison to clearly distinguish between those two values.