[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  /**
   4   * Prime Finite Fields
   5   *
   6   * Utilizes the factory design pattern
   7   *
   8   * PHP version 5 and 7
   9   *
  10   * @category  Math
  11   * @package   BigInteger
  12   * @author    Jim Wigginton <[email protected]>
  13   * @copyright 2017 Jim Wigginton
  14   * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
  15   * @link      http://pear.php.net/package/Math_BigInteger
  16   */
  17  
  18  namespace phpseclib3\Math;
  19  
  20  use phpseclib3\Math\Common\FiniteField;
  21  use phpseclib3\Math\PrimeField\Integer;
  22  
  23  /**
  24   * Prime Finite Fields
  25   *
  26   * @package Math
  27   * @author  Jim Wigginton <[email protected]>
  28   * @access  public
  29   */
  30  class PrimeField extends FiniteField
  31  {
  32      /**
  33       * Instance Counter
  34       *
  35       * @var int
  36       */
  37      private static $instanceCounter = 0;
  38  
  39      /**
  40       * Keeps track of current instance
  41       *
  42       * @var int
  43       */
  44      protected $instanceID;
  45  
  46      /**
  47       * Default constructor
  48       */
  49      public function __construct(BigInteger $modulo)
  50      {
  51          //if (!$modulo->isPrime()) {
  52          //    throw new \UnexpectedValueException('PrimeField requires a prime number be passed to the constructor');
  53          //}
  54  
  55          $this->modulo = $modulo;
  56  
  57          $this->instanceID = self::$instanceCounter++;
  58          Integer::setModulo($this->instanceID, $modulo);
  59          Integer::setRecurringModuloFunction($this->instanceID, $modulo->createRecurringModuloFunction());
  60      }
  61  
  62      /**
  63       * Use a custom defined modular reduction function
  64       *
  65       * @return void
  66       */
  67      public function setReduction(\Closure $func)
  68      {
  69          $this->reduce = $func->bindTo($this, $this);
  70      }
  71  
  72      /**
  73       * Returns an instance of a dynamically generated PrimeFieldInteger class
  74       *
  75       * @return Integer
  76       */
  77      public function newInteger(BigInteger $num)
  78      {
  79          return new Integer($this->instanceID, $num);
  80      }
  81  
  82      /**
  83       * Returns an integer on the finite field between one and the prime modulo
  84       *
  85       * @return Integer
  86       */
  87      public function randomInteger()
  88      {
  89          static $one;
  90          if (!isset($one)) {
  91              $one = new BigInteger(1);
  92          }
  93  
  94          return new Integer($this->instanceID, BigInteger::randomRange($one, Integer::getModulo($this->instanceID)));
  95      }
  96  
  97      /**
  98       * Returns the length of the modulo in bytes
  99       *
 100       * @return int
 101       */
 102      public function getLengthInBytes()
 103      {
 104          return Integer::getModulo($this->instanceID)->getLengthInBytes();
 105      }
 106  
 107      /**
 108       * Returns the length of the modulo in bits
 109       *
 110       * @return int
 111       */
 112      public function getLength()
 113      {
 114          return Integer::getModulo($this->instanceID)->getLength();
 115      }
 116  
 117      /**
 118       *  Destructor
 119       */
 120      public function __destruct()
 121      {
 122          Integer::cleanupCache($this->instanceID);
 123      }
 124  }