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827 | daniel-mar | 1 | <?php |
2 | |||
3 | /** |
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4 | * Prime Finite Fields |
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5 | * |
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6 | * PHP version 5 and 7 |
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7 | * |
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874 | daniel-mar | 8 | * @category Math |
9 | * @package BigInteger |
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827 | daniel-mar | 10 | * @author Jim Wigginton <terrafrost@php.net> |
11 | * @copyright 2017 Jim Wigginton |
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12 | * @license http://www.opensource.org/licenses/mit-license.html MIT License |
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13 | */ |
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14 | |||
15 | namespace phpseclib3\Math\PrimeField; |
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16 | |||
17 | use ParagonIE\ConstantTime\Hex; |
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18 | use phpseclib3\Math\BigInteger; |
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19 | use phpseclib3\Math\Common\FiniteField\Integer as Base; |
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20 | |||
21 | /** |
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22 | * Prime Finite Fields |
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23 | * |
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874 | daniel-mar | 24 | * @package Math |
827 | daniel-mar | 25 | * @author Jim Wigginton <terrafrost@php.net> |
874 | daniel-mar | 26 | * @access public |
827 | daniel-mar | 27 | */ |
28 | class Integer extends Base |
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29 | { |
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30 | /** |
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31 | * Holds the PrimeField's value |
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32 | * |
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33 | * @var BigInteger |
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34 | */ |
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35 | protected $value; |
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36 | |||
37 | /** |
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38 | * Keeps track of current instance |
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39 | * |
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40 | * @var int |
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41 | */ |
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42 | protected $instanceID; |
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43 | |||
44 | /** |
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45 | * Holds the PrimeField's modulo |
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46 | * |
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47 | * @var array<int, BigInteger> |
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48 | */ |
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49 | protected static $modulo; |
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50 | |||
51 | /** |
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52 | * Holds a pre-generated function to perform modulo reductions |
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53 | * |
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54 | * @var array<int, callable(BigInteger):BigInteger> |
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55 | */ |
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56 | protected static $reduce; |
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57 | |||
58 | /** |
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59 | * Zero |
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60 | * |
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61 | * @var BigInteger |
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62 | */ |
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63 | protected static $zero; |
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64 | |||
65 | /** |
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66 | * Default constructor |
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67 | * |
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68 | * @param int $instanceID |
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69 | */ |
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70 | public function __construct($instanceID, BigInteger $num = null) |
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71 | { |
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72 | $this->instanceID = $instanceID; |
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73 | if (!isset($num)) { |
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74 | $this->value = clone static::$zero[static::class]; |
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75 | } else { |
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76 | $reduce = static::$reduce[$instanceID]; |
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77 | $this->value = $reduce($num); |
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78 | } |
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79 | } |
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80 | |||
81 | /** |
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82 | * Set the modulo for a given instance |
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83 | * |
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84 | * @param int $instanceID |
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85 | * @return void |
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86 | */ |
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87 | public static function setModulo($instanceID, BigInteger $modulo) |
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88 | { |
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89 | static::$modulo[$instanceID] = $modulo; |
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90 | } |
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91 | |||
92 | /** |
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93 | * Set the modulo for a given instance |
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94 | * |
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95 | * @param int $instanceID |
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96 | * @return void |
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97 | */ |
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98 | public static function setRecurringModuloFunction($instanceID, callable $function) |
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99 | { |
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100 | static::$reduce[$instanceID] = $function; |
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101 | if (!isset(static::$zero[static::class])) { |
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102 | static::$zero[static::class] = new BigInteger(); |
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103 | } |
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104 | } |
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105 | |||
106 | /** |
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107 | * Delete the modulo for a given instance |
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108 | */ |
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109 | public static function cleanupCache($instanceID) |
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110 | { |
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111 | unset(static::$modulo[$instanceID]); |
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112 | unset(static::$reduce[$instanceID]); |
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113 | } |
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114 | |||
115 | /** |
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116 | * Returns the modulo |
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117 | * |
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118 | * @param int $instanceID |
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119 | * @return BigInteger |
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120 | */ |
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121 | public static function getModulo($instanceID) |
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122 | { |
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123 | return static::$modulo[$instanceID]; |
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124 | } |
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125 | |||
126 | /** |
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127 | * Tests a parameter to see if it's of the right instance |
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128 | * |
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129 | * Throws an exception if the incorrect class is being utilized |
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130 | * |
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131 | * @return void |
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132 | */ |
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133 | public static function checkInstance(self $x, self $y) |
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134 | { |
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135 | if ($x->instanceID != $y->instanceID) { |
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136 | throw new \UnexpectedValueException('The instances of the two PrimeField\Integer objects do not match'); |
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137 | } |
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138 | } |
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139 | |||
140 | /** |
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141 | * Tests the equality of two numbers. |
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142 | * |
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143 | * @return bool |
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144 | */ |
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145 | public function equals(self $x) |
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146 | { |
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147 | static::checkInstance($this, $x); |
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148 | |||
149 | return $this->value->equals($x->value); |
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150 | } |
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151 | |||
152 | /** |
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153 | * Compares two numbers. |
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154 | * |
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155 | * @return int |
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156 | */ |
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157 | public function compare(self $x) |
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158 | { |
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159 | static::checkInstance($this, $x); |
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160 | |||
161 | return $this->value->compare($x->value); |
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162 | } |
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163 | |||
164 | /** |
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165 | * Adds two PrimeFieldIntegers. |
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166 | * |
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167 | * @return static |
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168 | */ |
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169 | public function add(self $x) |
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170 | { |
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171 | static::checkInstance($this, $x); |
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172 | |||
173 | $temp = new static($this->instanceID); |
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174 | $temp->value = $this->value->add($x->value); |
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175 | if ($temp->value->compare(static::$modulo[$this->instanceID]) >= 0) { |
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176 | $temp->value = $temp->value->subtract(static::$modulo[$this->instanceID]); |
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177 | } |
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178 | |||
179 | return $temp; |
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180 | } |
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181 | |||
182 | /** |
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183 | * Subtracts two PrimeFieldIntegers. |
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184 | * |
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185 | * @return static |
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186 | */ |
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187 | public function subtract(self $x) |
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188 | { |
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189 | static::checkInstance($this, $x); |
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190 | |||
191 | $temp = new static($this->instanceID); |
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192 | $temp->value = $this->value->subtract($x->value); |
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193 | if ($temp->value->isNegative()) { |
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194 | $temp->value = $temp->value->add(static::$modulo[$this->instanceID]); |
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195 | } |
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196 | |||
197 | return $temp; |
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198 | } |
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199 | |||
200 | /** |
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201 | * Multiplies two PrimeFieldIntegers. |
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202 | * |
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203 | * @return static |
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204 | */ |
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205 | public function multiply(self $x) |
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206 | { |
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207 | static::checkInstance($this, $x); |
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208 | |||
209 | return new static($this->instanceID, $this->value->multiply($x->value)); |
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210 | } |
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211 | |||
212 | /** |
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213 | * Divides two PrimeFieldIntegers. |
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214 | * |
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215 | * @return static |
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216 | */ |
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217 | public function divide(self $x) |
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218 | { |
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219 | static::checkInstance($this, $x); |
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220 | |||
221 | $denominator = $x->value->modInverse(static::$modulo[$this->instanceID]); |
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222 | return new static($this->instanceID, $this->value->multiply($denominator)); |
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223 | } |
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224 | |||
225 | /** |
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226 | * Performs power operation on a PrimeFieldInteger. |
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227 | * |
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228 | * @return static |
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229 | */ |
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230 | public function pow(BigInteger $x) |
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231 | { |
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232 | $temp = new static($this->instanceID); |
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233 | $temp->value = $this->value->powMod($x, static::$modulo[$this->instanceID]); |
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234 | |||
235 | return $temp; |
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236 | } |
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237 | |||
238 | /** |
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239 | * Calculates the square root |
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240 | * |
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241 | * @link https://en.wikipedia.org/wiki/Tonelli%E2%80%93Shanks_algorithm |
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242 | * @return static|false |
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243 | */ |
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244 | public function squareRoot() |
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245 | { |
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246 | static $one, $two; |
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247 | if (!isset($one)) { |
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248 | $one = new BigInteger(1); |
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249 | $two = new BigInteger(2); |
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250 | } |
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251 | $reduce = static::$reduce[$this->instanceID]; |
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252 | $p_1 = static::$modulo[$this->instanceID]->subtract($one); |
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253 | $q = clone $p_1; |
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254 | $s = BigInteger::scan1divide($q); |
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255 | list($pow) = $p_1->divide($two); |
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256 | for ($z = $one; !$z->equals(static::$modulo[$this->instanceID]); $z = $z->add($one)) { |
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257 | $temp = $z->powMod($pow, static::$modulo[$this->instanceID]); |
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258 | if ($temp->equals($p_1)) { |
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259 | break; |
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260 | } |
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261 | } |
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262 | |||
263 | $m = new BigInteger($s); |
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264 | $c = $z->powMod($q, static::$modulo[$this->instanceID]); |
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265 | $t = $this->value->powMod($q, static::$modulo[$this->instanceID]); |
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266 | list($temp) = $q->add($one)->divide($two); |
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267 | $r = $this->value->powMod($temp, static::$modulo[$this->instanceID]); |
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268 | |||
269 | while (!$t->equals($one)) { |
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270 | $i = clone $one; |
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271 | |||
272 | while (!$t->powMod($two->pow($i), static::$modulo[$this->instanceID])->equals($one)) { |
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273 | $i = $i->add($one); |
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274 | } |
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275 | |||
276 | if ($i->compare($m) >= 0) { |
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277 | return false; |
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278 | } |
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279 | $b = $c->powMod($two->pow($m->subtract($i)->subtract($one)), static::$modulo[$this->instanceID]); |
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280 | $m = $i; |
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281 | $c = $reduce($b->multiply($b)); |
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282 | $t = $reduce($t->multiply($c)); |
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283 | $r = $reduce($r->multiply($b)); |
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284 | } |
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285 | |||
286 | return new static($this->instanceID, $r); |
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287 | } |
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288 | |||
289 | /** |
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290 | * Is Odd? |
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291 | * |
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292 | * @return bool |
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293 | */ |
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294 | public function isOdd() |
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295 | { |
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296 | return $this->value->isOdd(); |
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297 | } |
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298 | |||
299 | /** |
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300 | * Negate |
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301 | * |
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302 | * A negative number can be written as 0-12. With modulos, 0 is the same thing as the modulo |
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303 | * so 0-12 is the same thing as modulo-12 |
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304 | * |
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305 | * @return static |
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306 | */ |
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307 | public function negate() |
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308 | { |
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309 | return new static($this->instanceID, static::$modulo[$this->instanceID]->subtract($this->value)); |
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310 | } |
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311 | |||
312 | /** |
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313 | * Converts an Integer to a byte string (eg. base-256). |
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314 | * |
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315 | * @return string |
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316 | */ |
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317 | public function toBytes() |
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318 | { |
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319 | $length = static::$modulo[$this->instanceID]->getLengthInBytes(); |
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320 | return str_pad($this->value->toBytes(), $length, "\0", STR_PAD_LEFT); |
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321 | } |
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322 | |||
323 | /** |
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324 | * Converts an Integer to a hex string (eg. base-16). |
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325 | * |
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326 | * @return string |
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327 | */ |
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328 | public function toHex() |
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329 | { |
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330 | return Hex::encode($this->toBytes()); |
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331 | } |
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332 | |||
333 | /** |
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334 | * Converts an Integer to a bit string (eg. base-2). |
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335 | * |
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336 | * @return string |
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337 | */ |
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338 | public function toBits() |
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339 | { |
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340 | // return $this->value->toBits(); |
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341 | static $length; |
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342 | if (!isset($length)) { |
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343 | $length = static::$modulo[$this->instanceID]->getLength(); |
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344 | } |
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345 | |||
346 | return str_pad($this->value->toBits(), $length, '0', STR_PAD_LEFT); |
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347 | } |
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348 | |||
349 | /** |
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350 | * Returns the w-ary non-adjacent form (wNAF) |
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351 | * |
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352 | * @param int $w optional |
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353 | * @return array<int, int> |
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354 | */ |
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355 | public function getNAF($w = 1) |
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356 | { |
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357 | $w++; |
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358 | |||
359 | $mask = new BigInteger((1 << $w) - 1); |
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360 | $sub = new BigInteger(1 << $w); |
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361 | //$sub = new BigInteger(1 << ($w - 1)); |
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362 | $d = $this->toBigInteger(); |
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363 | $d_i = []; |
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364 | |||
365 | $i = 0; |
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366 | while ($d->compare(static::$zero[static::class]) > 0) { |
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367 | if ($d->isOdd()) { |
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368 | // start mods |
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369 | |||
370 | $bigInteger = $d->testBit($w - 1) ? |
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371 | $d->bitwise_and($mask)->subtract($sub) : |
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372 | //$sub->subtract($d->bitwise_and($mask)) : |
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373 | $d->bitwise_and($mask); |
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374 | // end mods |
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375 | $d = $d->subtract($bigInteger); |
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376 | $d_i[$i] = (int) $bigInteger->toString(); |
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377 | } else { |
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378 | $d_i[$i] = 0; |
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379 | } |
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380 | $shift = !$d->equals(static::$zero[static::class]) && $d->bitwise_and($mask)->equals(static::$zero[static::class]) ? $w : 1; // $w or $w + 1? |
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381 | $d = $d->bitwise_rightShift($shift); |
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382 | while (--$shift > 0) { |
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383 | $d_i[++$i] = 0; |
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384 | } |
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385 | $i++; |
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386 | } |
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387 | |||
388 | return $d_i; |
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389 | } |
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390 | |||
391 | /** |
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392 | * Converts an Integer to a BigInteger |
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393 | * |
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394 | * @return BigInteger |
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395 | */ |
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396 | public function toBigInteger() |
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397 | { |
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398 | return clone $this->value; |
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399 | } |
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400 | |||
401 | /** |
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402 | * __toString() magic method |
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403 | * |
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874 | daniel-mar | 404 | * @access public |
827 | daniel-mar | 405 | * @return string |
406 | */ |
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407 | public function __toString() |
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408 | { |
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409 | return (string) $this->value; |
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410 | } |
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411 | |||
412 | /** |
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413 | * __debugInfo() magic method |
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414 | * |
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874 | daniel-mar | 415 | * @access public |
827 | daniel-mar | 416 | * @return array |
417 | */ |
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418 | public function __debugInfo() |
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419 | { |
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420 | return ['value' => $this->toHex()]; |
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421 | } |
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422 | } |