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 |