| Total Complexity | 58 |
| Total Lines | 291 |
| Duplicated Lines | 0 % |
| Changes | 0 | ||
Complex classes like OATH_OCRAParser often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use OATH_OCRAParser, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 3 | class OATH_OCRAParser { |
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| 4 | |||
| 5 | private $key = NULL; |
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| 6 | |||
| 7 | private $OCRASuite = NULL; |
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| 8 | |||
| 9 | private $OCRAVersion = NULL; |
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| 10 | |||
| 11 | private $CryptoFunctionType = NULL; |
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| 12 | private $CryptoFunctionHash = NULL; |
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| 13 | private $CryptoFunctionHashLength = NULL; |
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| 14 | private $CryptoFunctionTruncation = NULL; |
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| 15 | |||
| 16 | private $C = FALSE; |
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| 17 | private $Q = FALSE; |
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| 18 | private $QType = 'N'; |
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| 19 | private $QLength = 8; |
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| 20 | |||
| 21 | private $P = FALSE; |
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| 22 | private $PType = 'SHA1'; |
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| 23 | private $PLength = 20; |
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| 24 | |||
| 25 | private $S = FALSE; |
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| 26 | private $SLength = 64; |
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| 27 | |||
| 28 | private $T = FALSE; |
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| 29 | private $TLength = 60; // 1M |
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| 30 | private $TPeriods = array('H' => 3600, 'M' => 60, 'S' => 1); |
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| 31 | |||
| 32 | private $supportedHashFunctions = array('SHA1' => 20, 'SHA256' => 32, 'SHA512' => 64); |
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| 33 | |||
| 34 | |||
| 35 | public function __construct($ocraSuite) { |
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| 37 | } |
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| 38 | |||
| 39 | /** |
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| 40 | * Inspired by https://github.com/bdauvergne/python-oath |
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| 41 | */ |
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| 42 | private function parseOCRASuite($ocraSuite) { |
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| 43 | if (!is_string($ocraSuite)) { |
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| 44 | throw new Exception('OCRASuite not in string format: ' . var_export($ocraSuite, TRUE)); |
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| 45 | } |
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| 46 | |||
| 47 | $ocraSuite = strtoupper($ocraSuite); |
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| 48 | $this->OCRASuite = $ocraSuite; |
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| 49 | |||
| 50 | $s = explode(':', $ocraSuite); |
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| 51 | if (count($s) != 3) { |
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| 52 | throw new Exception('Invalid OCRASuite format: ' . var_export($ocraSuite, TRUE)); |
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| 53 | } |
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| 54 | |||
| 55 | $algo = explode('-', $s[0]); |
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| 56 | if (count($algo) != 2) { |
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| 57 | throw new Exception('Invalid OCRA version: ' . var_export($s[0], TRUE)); |
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| 58 | } |
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| 59 | |||
| 60 | if ($algo[0] !== 'OCRA') { |
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| 61 | throw new Exception('Unsupported OCRA algorithm: ' . var_export($algo[0], TRUE)); |
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| 62 | } |
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| 63 | |||
| 64 | if ($algo[1] !== '1') { |
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| 65 | throw new Exception('Unsupported OCRA version: ' . var_export($algo[1], TRUE)); |
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| 66 | } |
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| 67 | $this->OCRAVersion = $algo[1]; |
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| 68 | |||
| 69 | $cf = explode('-', $s[1]); |
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| 70 | if (count($cf) != 3) { |
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| 71 | throw new Exception('Invalid OCRA suite crypto function: ' . var_export($s[1], TRUE)); |
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| 72 | } |
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| 73 | |||
| 74 | if ($cf[0] !== 'HOTP') { |
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| 75 | throw new Exception('Unsupported OCRA suite crypto function: ' . var_export($cf[0], TRUE)); |
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| 76 | } |
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| 77 | $this->CryptoFunctionType = $cf[0]; |
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| 78 | |||
| 79 | if (!array_key_exists($cf[1], $this->supportedHashFunctions)) { |
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| 80 | throw new Exception('Unsupported hash function in OCRA suite crypto function: ' . var_export($cf[1], TRUE)); |
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| 81 | } |
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| 82 | $this->CryptoFunctionHash = $cf[1]; |
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| 83 | $this->CryptoFunctionHashLength = $this->supportedHashFunctions[$cf[1]]; |
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| 84 | |||
| 85 | if (!preg_match('/^\d+$/', $cf[2]) || (($cf[2] < 4 || $cf[2] > 10) && $cf[2] != 0)) { |
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| 86 | throw new Exception('Invalid OCRA suite crypto function truncation length: ' . var_export($cf[2], TRUE)); |
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| 87 | } |
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| 88 | $this->CryptoFunctionTruncation = intval($cf[2]); |
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| 89 | |||
| 90 | $di = explode('-', $s[2]); |
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| 91 | if (count($cf) == 0) { |
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| 92 | throw new Exception('Invalid OCRA suite data input: ' . var_export($s[2], TRUE)); |
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| 93 | } |
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| 94 | |||
| 95 | $data_input = array(); |
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| 96 | foreach($di as $elem) { |
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| 97 | $letter = $elem[0]; |
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| 98 | if (array_key_exists($letter, $data_input)) { |
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| 99 | throw new Exception('Duplicate field in OCRA suite data input: ' . var_export($elem, TRUE)); |
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| 100 | } |
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| 101 | $data_input[$letter] = 1; |
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| 102 | |||
| 103 | if ($letter === 'C' && strlen($elem) == 1) { |
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| 104 | $this->C = TRUE; |
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| 105 | } elseif ($letter === 'Q') { |
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| 106 | if (strlen($elem) == 1) { |
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| 107 | $this->Q = TRUE; |
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| 108 | } elseif (preg_match('/^Q([AHN])(\d+)$/', $elem, $match)) { |
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| 109 | $q_len = intval($match[2]); |
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| 110 | if ($q_len < 4 || $q_len > 64) { |
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| 111 | throw new Exception('Invalid OCRA suite data input question length: ' . var_export($q_len, TRUE)); |
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| 112 | } |
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| 113 | $this->Q = TRUE; |
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| 114 | $this->QType = $match[1]; |
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| 115 | $this->QLength = $q_len; |
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| 116 | } else { |
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| 117 | throw new Exception('Invalid OCRA suite data input question: ' . var_export($elem, TRUE)); |
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| 118 | } |
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| 119 | } elseif ($letter === 'P') { |
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| 120 | if (strlen($elem) == 1) { |
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| 121 | $this->P = TRUE; |
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| 122 | } else { |
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| 123 | $p_algo = substr($elem, 1); |
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| 124 | if (!array_key_exists($p_algo, $this->supportedHashFunctions)) { |
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| 125 | throw new Exception('Unsupported OCRA suite PIN hash function: ' . var_export($elem, TRUE)); |
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| 126 | } |
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| 127 | $this->P = TRUE; |
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| 128 | $this->PType = $p_algo; |
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| 129 | $this->PLength = $this->supportedHashFunctions[$p_algo]; |
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| 130 | } |
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| 131 | } elseif ($letter === 'S') { |
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| 132 | if (strlen($elem) == 1) { |
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| 133 | $this->S = TRUE; |
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| 134 | } elseif (preg_match('/^S(\d+)$/', $elem, $match)) { |
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| 135 | $s_len = intval($match[1]); |
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| 136 | if ($s_len <= 0 || $s_len > 512) { |
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| 137 | throw new Exception('Invalid OCRA suite data input session information length: ' . var_export($s_len, TRUE)); |
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| 138 | } |
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| 139 | |||
| 140 | $this->S = TRUE; |
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| 141 | $this->SLength = $s_len; |
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| 142 | } else { |
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| 143 | throw new Exception('Invalid OCRA suite data input session information length: ' . var_export($elem, TRUE)); |
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| 144 | } |
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| 145 | } elseif ($letter === 'T') { |
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| 146 | if (strlen($elem) == 1) { |
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| 147 | $this->T = TRUE; |
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| 148 | } elseif (preg_match('/^T(\d+[HMS])+$/', $elem)) { |
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| 149 | preg_match_all('/(\d+)([HMS])/', $elem, $match); |
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| 150 | |||
| 151 | if (count($match[1]) !== count(array_unique($match[2]))) { |
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| 152 | throw new Exception('Duplicate definitions in OCRA suite data input timestamp: ' . var_export($elem, TRUE)); |
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| 153 | } |
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| 154 | |||
| 155 | $length = 0; |
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| 156 | for ($i = 0; $i < count($match[1]); $i++) { |
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| 157 | $length += intval($match[1][$i]) * $this->TPeriods[$match[2][$i]]; |
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| 158 | } |
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| 159 | if ($length <= 0) { |
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| 160 | throw new Exception('Invalid OCRA suite data input timestamp: ' . var_export($elem, TRUE)); |
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| 161 | } |
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| 162 | |||
| 163 | $this->T = TRUE; |
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| 164 | $this->TLength = $length; |
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| 165 | } else { |
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| 166 | throw new Exception('Invalid OCRA suite data input timestamp: ' . var_export($elem, TRUE)); |
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| 167 | } |
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| 168 | } else { |
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| 169 | throw new Exception('Unsupported OCRA suite data input field: ' . var_export($elem, TRUE)); |
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| 170 | } |
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| 171 | } |
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| 172 | |||
| 173 | if (!$this->Q) { |
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| 174 | throw new Exception('OCRA suite data input question not defined: ' . var_export($s[2], TRUE)); |
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| 175 | } |
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| 176 | } |
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| 177 | |||
| 178 | public function generateChallenge() { |
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| 179 | $q_length = $this->QLength; |
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| 180 | $q_type = $this->QType; |
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| 181 | |||
| 182 | $bytes = self::generateRandomBytes($q_length); |
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| 183 | |||
| 184 | switch($q_type) { |
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| 185 | case 'A': |
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| 186 | $challenge = base64_encode($bytes); |
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| 187 | $tr = implode("", unpack('H*', $bytes)); |
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| 188 | $challenge = rtrim(strtr($challenge, '+/', $tr), '='); |
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| 189 | break; |
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| 190 | case 'H': |
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| 191 | $challenge = implode("", unpack('H*', $bytes)); |
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| 192 | break; |
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| 193 | case 'N': |
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| 194 | $challenge = implode("", unpack('N*', $bytes)); |
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| 195 | break; |
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| 196 | default: |
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| 197 | throw new Exception('Unsupported OCRASuite challenge type: ' . var_export($q_type, TRUE)); |
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| 198 | break; |
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| 199 | } |
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| 200 | |||
| 201 | $challenge = substr($challenge, 0, $q_length); |
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| 202 | |||
| 203 | return $challenge; |
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| 204 | } |
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| 205 | |||
| 206 | |||
| 207 | public function generateSessionInformation() { |
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| 208 | if (!$this->S) { |
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| 209 | throw new Exception('Session information not defined in OCRASuite: ' . var_export($this->OCRASuite, TRUE)); |
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| 210 | } |
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| 211 | |||
| 212 | $s_length = $this->SLength; |
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| 213 | $bytes = self::generateRandomBytes($s_length); |
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| 214 | |||
| 215 | // The OCRA spec doesn't specify that the session data should be hexadecimal. |
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| 216 | // However the reference implementation in the RFC does treat it as hex. |
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| 217 | $session = bin2hex($bytes); |
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| 218 | |||
| 219 | $session = substr($session, 0, $s_length); |
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| 220 | |||
| 221 | return $session; |
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| 222 | } |
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| 223 | |||
| 224 | /** |
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| 225 | * Borrowed from SimpleSAMLPHP http://simplesamlphp.org/ |
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| 226 | */ |
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| 227 | public static function generateRandomBytesMTrand($length) { |
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| 228 | |||
| 229 | /* Use mt_rand to generate $length random bytes. */ |
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| 230 | $data = ''; |
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| 231 | for($i = 0; $i < $length; $i++) { |
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| 232 | $data .= chr(mt_rand(0, 255)); |
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| 233 | } |
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| 234 | |||
| 235 | return $data; |
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| 236 | } |
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| 237 | |||
| 238 | |||
| 239 | /** |
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| 240 | * Borrowed from SimpleSAMLPHP http://simplesamlphp.org/ |
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| 241 | */ |
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| 242 | public static function generateRandomBytes($length, $fallback = TRUE) { |
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| 276 | } |
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| 277 | |||
| 278 | |||
| 279 | /** |
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| 280 | * Constant time string comparison, see http://codahale.com/a-lesson-in-timing-attacks/ |
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| 281 | */ |
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| 282 | public static function constEqual($s1, $s2) { |
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| 297 |