<?php
if (class_exists('ParagonIE_Sodium_Core_ChaCha20_Ctx', false)) {
return;
}
/**
* Class ParagonIE_Sodium_Core32_ChaCha20_Ctx
*/
class ParagonIE_Sodium_Core32_ChaCha20_Ctx extends ParagonIE_Sodium_Core32_Util implements ArrayAccess
{
/**
* @var SplFixedArray internally, <int, ParagonIE_Sodium_Core32_Int32>
*/
protected $container;
/**
* ParagonIE_Sodium_Core_ChaCha20_Ctx constructor.
*
* @internal You should not use this directly from another application
*
* @param string $key ChaCha20 key.
* @param string $iv Initialization Vector (a.k.a. nonce).
* @param string $counter The initial counter value.
* Defaults to 8 0x00 bytes.
* @throws InvalidArgumentException
* @throws SodiumException
* @throws TypeError
*/
public function __construct($key = '', $iv = '', $counter = '')
{
if (self::strlen($key) !== 32) {
throw new InvalidArgumentException('ChaCha20 expects a 256-bit key.');
}
if (self::strlen($iv) !== 8) {
throw new InvalidArgumentException('ChaCha20 expects a 64-bit nonce.');
}
$this->container = new SplFixedArray(16);
/* "expand 32-byte k" as per ChaCha20 spec */
$this->container[0] = new ParagonIE_Sodium_Core32_Int32(array(0x6170, 0x7865));
$this->container[1] = new ParagonIE_Sodium_Core32_Int32(array(0x3320, 0x646e));
$this->container[2] = new ParagonIE_Sodium_Core32_Int32(array(0x7962, 0x2d32));
$this->container[3] = new ParagonIE_Sodium_Core32_Int32(array(0x6b20, 0x6574));
$this->container[4] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 0, 4));
$this->container[5] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 4, 4));
$this->container[6] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 8, 4));
$this->container[7] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 12, 4));
$this->container[8] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 16, 4));
$this->container[9] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 20, 4));
$this->container[10] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 24, 4));
$this->container[11] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 28, 4));
if (empty($counter)) {
$this->container[12] = new ParagonIE_Sodium_Core32_Int32();
$this->container[13] = new ParagonIE_Sodium_Core32_Int32();
} else {
$this->container[12] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($counter, 0, 4));
$this->container[13] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($counter, 4, 4));
}
$this->container[14] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($iv, 0, 4));
$this->container[15] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($iv, 4, 4));
}
/**
* @internal You should not use this directly from another application
*
* @param int $offset
* @param int|ParagonIE_Sodium_Core32_Int32 $value
* @return void
*/
#[ReturnTypeWillChange]
public function offsetSet($offset, $value)
{
if (!is_int($offset)) {
throw new InvalidArgumentException('Expected an integer');
}
if ($value instanceof ParagonIE_Sodium_Core32_Int32) {
/*
} elseif (is_int($value)) {
$value = ParagonIE_Sodium_Core32_Int32::fromInt($value);
*/
} else {
throw new InvalidArgumentException('Expected an integer');
}
$this->container[$offset] = $value;
}
/**
* @internal You should not use this directly from another application
*
* @param int $offset
* @return bool
* @psalm-suppress MixedArrayOffset
*/
#[ReturnTypeWillChange]
public function offsetExists($offset)
{
return isset($this->container[$offset]);
}
/**
* @internal You should not use this directly from another application
*
* @param int $offset
* @return void
* @psalm-suppress MixedArrayOffset
*/
#[ReturnTypeWillChange]
public function offsetUnset($offset)
{
unset($this->container[$offset]);
}
/**
* @internal You should not use this directly from another application
*
* @param int $offset
* @return mixed|null
* @psalm-suppress MixedArrayOffset
*/
#[ReturnTypeWillChange]
public function offsetGet($offset)
{
return isset($this->container[$offset])
? $this->container[$offset]
: null;
}
}