[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  if (class_exists('ParagonIE_Sodium_Core_ChaCha20_Ctx', false)) {
   4      return;
   5  }
   6  
   7  /**
   8   * Class ParagonIE_Sodium_Core32_ChaCha20_Ctx
   9   */
  10  class ParagonIE_Sodium_Core32_ChaCha20_Ctx extends ParagonIE_Sodium_Core32_Util implements ArrayAccess
  11  {
  12      /**
  13       * @var SplFixedArray internally, <int, ParagonIE_Sodium_Core32_Int32>
  14       */
  15      protected $container;
  16  
  17      /**
  18       * ParagonIE_Sodium_Core_ChaCha20_Ctx constructor.
  19       *
  20       * @internal You should not use this directly from another application
  21       *
  22       * @param string $key     ChaCha20 key.
  23       * @param string $iv      Initialization Vector (a.k.a. nonce).
  24       * @param string $counter The initial counter value.
  25       *                        Defaults to 8 0x00 bytes.
  26       * @throws InvalidArgumentException
  27       * @throws SodiumException
  28       * @throws TypeError
  29       */
  30      public function __construct($key = '', $iv = '', $counter = '')
  31      {
  32          if (self::strlen($key) !== 32) {
  33              throw new InvalidArgumentException('ChaCha20 expects a 256-bit key.');
  34          }
  35          if (self::strlen($iv) !== 8) {
  36              throw new InvalidArgumentException('ChaCha20 expects a 64-bit nonce.');
  37          }
  38          $this->container = new SplFixedArray(16);
  39  
  40          /* "expand 32-byte k" as per ChaCha20 spec */
  41          $this->container[0]  = new ParagonIE_Sodium_Core32_Int32(array(0x6170, 0x7865));
  42          $this->container[1]  = new ParagonIE_Sodium_Core32_Int32(array(0x3320, 0x646e));
  43          $this->container[2]  = new ParagonIE_Sodium_Core32_Int32(array(0x7962, 0x2d32));
  44          $this->container[3]  = new ParagonIE_Sodium_Core32_Int32(array(0x6b20, 0x6574));
  45  
  46          $this->container[4]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 0, 4));
  47          $this->container[5]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 4, 4));
  48          $this->container[6]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 8, 4));
  49          $this->container[7]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 12, 4));
  50          $this->container[8]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 16, 4));
  51          $this->container[9]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 20, 4));
  52          $this->container[10] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 24, 4));
  53          $this->container[11] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 28, 4));
  54  
  55          if (empty($counter)) {
  56              $this->container[12] = new ParagonIE_Sodium_Core32_Int32();
  57              $this->container[13] = new ParagonIE_Sodium_Core32_Int32();
  58          } else {
  59              $this->container[12] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($counter, 0, 4));
  60              $this->container[13] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($counter, 4, 4));
  61          }
  62          $this->container[14] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($iv, 0, 4));
  63          $this->container[15] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($iv, 4, 4));
  64      }
  65  
  66      /**
  67       * @internal You should not use this directly from another application
  68       *
  69       * @param int $offset
  70       * @param int|ParagonIE_Sodium_Core32_Int32 $value
  71       * @return void
  72       */
  73      #[ReturnTypeWillChange]
  74      public function offsetSet($offset, $value)
  75      {
  76          if (!is_int($offset)) {
  77              throw new InvalidArgumentException('Expected an integer');
  78          }
  79          if ($value instanceof ParagonIE_Sodium_Core32_Int32) {
  80              /*
  81          } elseif (is_int($value)) {
  82              $value = ParagonIE_Sodium_Core32_Int32::fromInt($value);
  83              */
  84          } else {
  85              throw new InvalidArgumentException('Expected an integer');
  86          }
  87          $this->container[$offset] = $value;
  88      }
  89  
  90      /**
  91       * @internal You should not use this directly from another application
  92       *
  93       * @param int $offset
  94       * @return bool
  95       * @psalm-suppress MixedArrayOffset
  96       */
  97      #[ReturnTypeWillChange]
  98      public function offsetExists($offset)
  99      {
 100          return isset($this->container[$offset]);
 101      }
 102  
 103      /**
 104       * @internal You should not use this directly from another application
 105       *
 106       * @param int $offset
 107       * @return void
 108       * @psalm-suppress MixedArrayOffset
 109       */
 110      #[ReturnTypeWillChange]
 111      public function offsetUnset($offset)
 112      {
 113          unset($this->container[$offset]);
 114      }
 115  
 116      /**
 117       * @internal You should not use this directly from another application
 118       *
 119       * @param int $offset
 120       * @return mixed|null
 121       * @psalm-suppress MixedArrayOffset
 122       */
 123      #[ReturnTypeWillChange]
 124      public function offsetGet($offset)
 125      {
 126          return isset($this->container[$offset])
 127              ? $this->container[$offset]
 128              : null;
 129      }
 130  }