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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 $c
  16       * @return string
  17       *
  18       * @throws SodiumException
  19       * @throws TypeError
  20       */
  21      public static function hChaCha20($in, $key, $c = null)
  22      {
  23          if (self::strlen($in) !== 16) {
  24              throw new SodiumException('Argument 1 must be 16 bytes');
  25          }
  26          if (self::strlen($key) !== 32) {
  27              throw new SodiumException('Argument 2 must be 32 bytes');
  28          }
  29          $ctx = array();
  30  
  31          if ($c === null) {
  32              $ctx[0] = 0x61707865;
  33              $ctx[1] = 0x3320646e;
  34              $ctx[2] = 0x79622d32;
  35              $ctx[3] = 0x6b206574;
  36          } else {
  37              $ctx[0] = self::load_4(self::substr($c,  0, 4));
  38              $ctx[1] = self::load_4(self::substr($c,  4, 4));
  39              $ctx[2] = self::load_4(self::substr($c,  8, 4));
  40              $ctx[3] = self::load_4(self::substr($c, 12, 4));
  41          }
  42          $ctx[4]  = self::load_4(self::substr($key,  0, 4));
  43          $ctx[5]  = self::load_4(self::substr($key,  4, 4));
  44          $ctx[6]  = self::load_4(self::substr($key,  8, 4));
  45          $ctx[7]  = self::load_4(self::substr($key, 12, 4));
  46          $ctx[8]  = self::load_4(self::substr($key, 16, 4));
  47          $ctx[9]  = self::load_4(self::substr($key, 20, 4));
  48          $ctx[10] = self::load_4(self::substr($key, 24, 4));
  49          $ctx[11] = self::load_4(self::substr($key, 28, 4));
  50          $ctx[12] = self::load_4(self::substr($in,   0, 4));
  51          $ctx[13] = self::load_4(self::substr($in,   4, 4));
  52          $ctx[14] = self::load_4(self::substr($in,   8, 4));
  53          $ctx[15] = self::load_4(self::substr($in,  12, 4));
  54          return self::hChaCha20Bytes($ctx);
  55      }
  56  
  57      /**
  58       * @param array $ctx
  59       * @return string
  60       * @throws TypeError
  61       */
  62      protected static function hChaCha20Bytes(array $ctx)
  63      {
  64          $x0  = (int) $ctx[0];
  65          $x1  = (int) $ctx[1];
  66          $x2  = (int) $ctx[2];
  67          $x3  = (int) $ctx[3];
  68          $x4  = (int) $ctx[4];
  69          $x5  = (int) $ctx[5];
  70          $x6  = (int) $ctx[6];
  71          $x7  = (int) $ctx[7];
  72          $x8  = (int) $ctx[8];
  73          $x9  = (int) $ctx[9];
  74          $x10 = (int) $ctx[10];
  75          $x11 = (int) $ctx[11];
  76          $x12 = (int) $ctx[12];
  77          $x13 = (int) $ctx[13];
  78          $x14 = (int) $ctx[14];
  79          $x15 = (int) $ctx[15];
  80  
  81          for ($i = 0; $i < 10; ++$i) {
  82              # QUARTERROUND( x0,  x4,  x8,  x12)
  83              list($x0, $x4, $x8, $x12) = self::quarterRound($x0, $x4, $x8, $x12);
  84  
  85              # QUARTERROUND( x1,  x5,  x9,  x13)
  86              list($x1, $x5, $x9, $x13) = self::quarterRound($x1, $x5, $x9, $x13);
  87  
  88              # QUARTERROUND( x2,  x6,  x10,  x14)
  89              list($x2, $x6, $x10, $x14) = self::quarterRound($x2, $x6, $x10, $x14);
  90  
  91              # QUARTERROUND( x3,  x7,  x11,  x15)
  92              list($x3, $x7, $x11, $x15) = self::quarterRound($x3, $x7, $x11, $x15);
  93  
  94              # QUARTERROUND( x0,  x5,  x10,  x15)
  95              list($x0, $x5, $x10, $x15) = self::quarterRound($x0, $x5, $x10, $x15);
  96  
  97              # QUARTERROUND( x1,  x6,  x11,  x12)
  98              list($x1, $x6, $x11, $x12) = self::quarterRound($x1, $x6, $x11, $x12);
  99  
 100              # QUARTERROUND( x2,  x7,  x8,  x13)
 101              list($x2, $x7, $x8, $x13) = self::quarterRound($x2, $x7, $x8, $x13);
 102  
 103              # QUARTERROUND( x3,  x4,  x9,  x14)
 104              list($x3, $x4, $x9, $x14) = self::quarterRound($x3, $x4, $x9, $x14);
 105          }
 106  
 107          return self::store32_le((int) ($x0  & 0xffffffff)) .
 108              self::store32_le((int) ($x1  & 0xffffffff)) .
 109              self::store32_le((int) ($x2  & 0xffffffff)) .
 110              self::store32_le((int) ($x3  & 0xffffffff)) .
 111              self::store32_le((int) ($x12 & 0xffffffff)) .
 112              self::store32_le((int) ($x13 & 0xffffffff)) .
 113              self::store32_le((int) ($x14 & 0xffffffff)) .
 114              self::store32_le((int) ($x15 & 0xffffffff));
 115      }
 116  }