/**
* read block to file
*/
protected function readCache() {
// cache should always be empty string when this function is called
// don't try to fill the cache when trying to write at the end of the unencrypted file when it coincides with new block
if ($this->cache === '' && !($this->position === $this->unencryptedSize && ($this->position % $this->unencryptedBlockSize) === 0)) {
// Get the data from the file handle
$data = parent::stream_read($this->util->getBlockSize());
$this->cache = $this->encryptionModule->decrypt($data);
}
}
/**
* read block to file
*/
protected function readCache()
{
// cache should always be empty string when this function is called
// don't try to fill the cache when trying to write at the end of the unencrypted file when it coincides with new block
if ($this->cache === '' && !($this->position === $this->unencryptedSize && $this->position % $this->unencryptedBlockSize === 0)) {
// Get the data from the file handle
$data = parent::stream_read($this->util->getBlockSize());
$position = (int) floor($this->position / $this->unencryptedBlockSize);
$numberOfChunks = (int) ($this->unencryptedSize / $this->unencryptedBlockSize);
if ($numberOfChunks === $position) {
$position .= 'end';
}
$this->cache = $this->encryptionModule->decrypt($data, $position);
}
}
/**
* Unregisters an encryption module
*
* @param IEncryptionModule $module
*/
public function unregisterEncryptionModule(IEncryptionModule $module)
{
unset($this->encryptionModules[$module->getId()]);
}
/**
* create header for encrypted file
*
* @param array $headerData
* @param IEncryptionModule $encryptionModule
* @return string
* @throws EncryptionHeaderToLargeException if header has to many arguments
* @throws EncryptionHeaderKeyExistsException if header key is already in use
*/
public function createHeader(array $headerData, IEncryptionModule $encryptionModule)
{
$header = self::HEADER_START . ':' . self::HEADER_ENCRYPTION_MODULE_KEY . ':' . $encryptionModule->getId() . ':';
foreach ($headerData as $key => $value) {
if (in_array($key, $this->ocHeaderKeys)) {
throw new EncryptionHeaderKeyExistsException($key);
}
$header .= $key . ':' . $value . ':';
}
$header .= self::HEADER_END;
if (strlen($header) > $this->getHeaderSize()) {
throw new EncryptionHeaderToLargeException();
}
$paddedHeader = str_pad($header, $this->headerSize, self::HEADER_PADDING_CHAR, STR_PAD_RIGHT);
return $paddedHeader;
}
