Ctx.php (3830B)
1 <?php 2 3 if (class_exists('ParagonIE_Sodium_Core_ChaCha20_Ctx', false)) { 4 return; 5 } 6 7 /** 8 * Class ParagonIE_Sodium_Core_ChaCha20_Ctx 9 */ 10 class ParagonIE_Sodium_Core_ChaCha20_Ctx extends ParagonIE_Sodium_Core_Util implements ArrayAccess 11 { 12 /** 13 * @var SplFixedArray internally, <int, int> 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 $counter The initial counter value. 25 * Defaults to 8 0x00 bytes. 26 * @throws InvalidArgumentException 27 * @throws TypeError 28 */ 29 public function __construct($key = '', $iv = '', $counter = '') 30 { 31 if (self::strlen($key) !== 32) { 32 throw new InvalidArgumentException('ChaCha20 expects a 256-bit key.'); 33 } 34 if (self::strlen($iv) !== 8) { 35 throw new InvalidArgumentException('ChaCha20 expects a 64-bit nonce.'); 36 } 37 $this->container = new SplFixedArray(16); 38 39 /* "expand 32-byte k" as per ChaCha20 spec */ 40 $this->container[0] = 0x61707865; 41 $this->container[1] = 0x3320646e; 42 $this->container[2] = 0x79622d32; 43 $this->container[3] = 0x6b206574; 44 $this->container[4] = self::load_4(self::substr($key, 0, 4)); 45 $this->container[5] = self::load_4(self::substr($key, 4, 4)); 46 $this->container[6] = self::load_4(self::substr($key, 8, 4)); 47 $this->container[7] = self::load_4(self::substr($key, 12, 4)); 48 $this->container[8] = self::load_4(self::substr($key, 16, 4)); 49 $this->container[9] = self::load_4(self::substr($key, 20, 4)); 50 $this->container[10] = self::load_4(self::substr($key, 24, 4)); 51 $this->container[11] = self::load_4(self::substr($key, 28, 4)); 52 53 if (empty($counter)) { 54 $this->container[12] = 0; 55 $this->container[13] = 0; 56 } else { 57 $this->container[12] = self::load_4(self::substr($counter, 0, 4)); 58 $this->container[13] = self::load_4(self::substr($counter, 4, 4)); 59 } 60 $this->container[14] = self::load_4(self::substr($iv, 0, 4)); 61 $this->container[15] = self::load_4(self::substr($iv, 4, 4)); 62 } 63 64 /** 65 * @internal You should not use this directly from another application 66 * 67 * @param int $offset 68 * @param int $value 69 * @return void 70 * @psalm-suppress MixedArrayOffset 71 */ 72 public function offsetSet($offset, $value) 73 { 74 if (!is_int($offset)) { 75 throw new InvalidArgumentException('Expected an integer'); 76 } 77 if (!is_int($value)) { 78 throw new InvalidArgumentException('Expected an integer'); 79 } 80 $this->container[$offset] = $value; 81 } 82 83 /** 84 * @internal You should not use this directly from another application 85 * 86 * @param int $offset 87 * @return bool 88 */ 89 public function offsetExists($offset) 90 { 91 return isset($this->container[$offset]); 92 } 93 94 /** 95 * @internal You should not use this directly from another application 96 * 97 * @param int $offset 98 * @return void 99 * @psalm-suppress MixedArrayOffset 100 */ 101 public function offsetUnset($offset) 102 { 103 unset($this->container[$offset]); 104 } 105 106 /** 107 * @internal You should not use this directly from another application 108 * 109 * @param int $offset 110 * @return mixed|null 111 * @psalm-suppress MixedArrayOffset 112 */ 113 public function offsetGet($offset) 114 { 115 return isset($this->container[$offset]) 116 ? $this->container[$offset] 117 : null; 118 } 119 }