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   1  <?php
   2  
   3  if (class_exists('ParagonIE_Sodium_Core_HChaCha20', false)) {
   4      return;
   5  }
   6  
   7  /**
   8   * Class ParagonIE_Sodium_Core_HChaCha20
   9   */
  10  class ParagonIE_Sodium_Core_HChaCha20 extends ParagonIE_Sodium_Core_ChaCha20
  11  {
  12      /**
  13       * @param string $in
  14       * @param string $key
  15       * @param string|null $c
  16       * @return string
  17       * @throws TypeError
  18       */
  19      public static function hChaCha20($in = '', $key = '', $c = null)
  20      {
  21          $ctx = array();
  22  
  23          if ($c === null) {
  24              $ctx[0] = 0x61707865;
  25              $ctx[1] = 0x3320646e;
  26              $ctx[2] = 0x79622d32;
  27              $ctx[3] = 0x6b206574;
  28          } else {
  29              $ctx[0] = self::load_4(self::substr($c,  0, 4));
  30              $ctx[1] = self::load_4(self::substr($c,  4, 4));
  31              $ctx[2] = self::load_4(self::substr($c,  8, 4));
  32              $ctx[3] = self::load_4(self::substr($c, 12, 4));
  33          }
  34          $ctx[4]  = self::load_4(self::substr($key,  0, 4));
  35          $ctx[5]  = self::load_4(self::substr($key,  4, 4));
  36          $ctx[6]  = self::load_4(self::substr($key,  8, 4));
  37          $ctx[7]  = self::load_4(self::substr($key, 12, 4));
  38          $ctx[8]  = self::load_4(self::substr($key, 16, 4));
  39          $ctx[9]  = self::load_4(self::substr($key, 20, 4));
  40          $ctx[10] = self::load_4(self::substr($key, 24, 4));
  41          $ctx[11] = self::load_4(self::substr($key, 28, 4));
  42          $ctx[12] = self::load_4(self::substr($in,   0, 4));
  43          $ctx[13] = self::load_4(self::substr($in,   4, 4));
  44          $ctx[14] = self::load_4(self::substr($in,   8, 4));
  45          $ctx[15] = self::load_4(self::substr($in,  12, 4));
  46          return self::hChaCha20Bytes($ctx);
  47      }
  48  
  49      /**
  50       * @param array $ctx
  51       * @return string
  52       * @throws TypeError
  53       */
  54      protected static function hChaCha20Bytes(array $ctx)
  55      {
  56          $x0  = (int) $ctx[0];
  57          $x1  = (int) $ctx[1];
  58          $x2  = (int) $ctx[2];
  59          $x3  = (int) $ctx[3];
  60          $x4  = (int) $ctx[4];
  61          $x5  = (int) $ctx[5];
  62          $x6  = (int) $ctx[6];
  63          $x7  = (int) $ctx[7];
  64          $x8  = (int) $ctx[8];
  65          $x9  = (int) $ctx[9];
  66          $x10 = (int) $ctx[10];
  67          $x11 = (int) $ctx[11];
  68          $x12 = (int) $ctx[12];
  69          $x13 = (int) $ctx[13];
  70          $x14 = (int) $ctx[14];
  71          $x15 = (int) $ctx[15];
  72  
  73          for ($i = 0; $i < 10; ++$i) {
  74              # QUARTERROUND( x0,  x4,  x8,  x12)
  75              list($x0, $x4, $x8, $x12) = self::quarterRound($x0, $x4, $x8, $x12);
  76  
  77              # QUARTERROUND( x1,  x5,  x9,  x13)
  78              list($x1, $x5, $x9, $x13) = self::quarterRound($x1, $x5, $x9, $x13);
  79  
  80              # QUARTERROUND( x2,  x6,  x10,  x14)
  81              list($x2, $x6, $x10, $x14) = self::quarterRound($x2, $x6, $x10, $x14);
  82  
  83              # QUARTERROUND( x3,  x7,  x11,  x15)
  84              list($x3, $x7, $x11, $x15) = self::quarterRound($x3, $x7, $x11, $x15);
  85  
  86              # QUARTERROUND( x0,  x5,  x10,  x15)
  87              list($x0, $x5, $x10, $x15) = self::quarterRound($x0, $x5, $x10, $x15);
  88  
  89              # QUARTERROUND( x1,  x6,  x11,  x12)
  90              list($x1, $x6, $x11, $x12) = self::quarterRound($x1, $x6, $x11, $x12);
  91  
  92              # QUARTERROUND( x2,  x7,  x8,  x13)
  93              list($x2, $x7, $x8, $x13) = self::quarterRound($x2, $x7, $x8, $x13);
  94  
  95              # QUARTERROUND( x3,  x4,  x9,  x14)
  96              list($x3, $x4, $x9, $x14) = self::quarterRound($x3, $x4, $x9, $x14);
  97          }
  98  
  99          return self::store32_le((int) ($x0  & 0xffffffff)) .
 100              self::store32_le((int) ($x1  & 0xffffffff)) .
 101              self::store32_le((int) ($x2  & 0xffffffff)) .
 102              self::store32_le((int) ($x3  & 0xffffffff)) .
 103              self::store32_le((int) ($x12 & 0xffffffff)) .
 104              self::store32_le((int) ($x13 & 0xffffffff)) .
 105              self::store32_le((int) ($x14 & 0xffffffff)) .
 106              self::store32_le((int) ($x15 & 0xffffffff));
 107      }
 108  }