File size: 7.04Kb
<?php
namespace PhpZip\Extra\Fields;
use PhpZip\Exception\ZipException;
use PhpZip\Extra\ExtraField;
use PhpZip\ZipFileInterface;
/**
* WinZip AES Extra Field.
*
* @see http://www.winzip.com/win/en/aes_info.htm AES Encryption Information: Encryption Specification AE-1 and AE-2 (WinZip Computing, S.L.)
* @see http://www.winzip.com/win/en/aes_tips.htm AES Coding Tips for Developers (WinZip Computing, S.L.)
* @author Ne-Lexa [email protected]
* @license MIT
*/
class WinZipAesEntryExtraField implements ExtraField
{
const DATA_SIZE = 7;
const VENDOR_ID = 17729; // 'A' | ('E' << 8);
/**
* Entries of this type <em>do</em> include the standard ZIP CRC-32 value.
* For use with @see WinZipAesEntryExtraField::setVendorVersion()}/@see WinZipAesEntryExtraField::getVendorVersion().
*/
const VV_AE_1 = 1;
/**
* Entries of this type do <em>not</em> include the standard ZIP CRC-32 value.
* For use with @see WinZipAesEntryExtraField::setVendorVersion()}/@see WinZipAesEntryExtraField::getVendorVersion().
*/
const VV_AE_2 = 2;
const KEY_STRENGTH_128BIT = 128;
const KEY_STRENGTH_192BIT = 192;
const KEY_STRENGTH_256BIT = 256;
protected static $keyStrengths = [
self::KEY_STRENGTH_128BIT => 0x01,
self::KEY_STRENGTH_192BIT => 0x02,
self::KEY_STRENGTH_256BIT => 0x03
];
protected static $encryptionMethods = [
self::KEY_STRENGTH_128BIT => ZipFileInterface::ENCRYPTION_METHOD_WINZIP_AES_128,
self::KEY_STRENGTH_192BIT => ZipFileInterface::ENCRYPTION_METHOD_WINZIP_AES_192,
self::KEY_STRENGTH_256BIT => ZipFileInterface::ENCRYPTION_METHOD_WINZIP_AES_256
];
/**
* Vendor version.
*
* @var int
*/
protected $vendorVersion = self::VV_AE_1;
/**
* Encryption strength.
*
* @var int
*/
protected $encryptionStrength = self::KEY_STRENGTH_256BIT;
/**
* Zip compression method.
*
* @var int
*/
protected $method;
/**
* Returns the Header ID (type) of this Extra Field.
* The Header ID is an unsigned short integer (two bytes)
* which must be constant during the life cycle of this object.
*
* @return int
*/
public static function getHeaderId()
{
return 0x9901;
}
/**
* Returns the vendor version.
*
* @see WinZipAesEntryExtraField::VV_AE_1
* @see WinZipAesEntryExtraField::VV_AE_2
*/
public function getVendorVersion()
{
return $this->vendorVersion & 0xffff;
}
/**
* Sets the vendor version.
*
* @see WinZipAesEntryExtraField::VV_AE_1
* @see WinZipAesEntryExtraField::VV_AE_2
* @param int $vendorVersion the vendor version.
* @throws ZipException Unsupport vendor version.
*/
public function setVendorVersion($vendorVersion)
{
if ($vendorVersion < self::VV_AE_1 || self::VV_AE_2 < $vendorVersion) {
throw new ZipException($vendorVersion);
}
$this->vendorVersion = $vendorVersion;
}
/**
* Returns vendor id.
*
* @return int
*/
public function getVendorId()
{
return self::VENDOR_ID;
}
/**
* @return bool|int
* @throws ZipException
*/
public function getKeyStrength()
{
return self::keyStrength($this->encryptionStrength);
}
/**
* @param int $encryptionStrength Encryption strength as bits.
* @return int
* @throws ZipException If unsupport encryption strength.
*/
public static function keyStrength($encryptionStrength)
{
$flipKeyStrength = array_flip(self::$keyStrengths);
if (!isset($flipKeyStrength[$encryptionStrength])) {
throw new ZipException("Unsupport encryption strength " . $encryptionStrength);
}
return $flipKeyStrength[$encryptionStrength];
}
/**
* Returns compression method.
*
* @return int
*/
public function getMethod()
{
return $this->method & 0xffff;
}
/**
* Internal encryption method.
*
* @return int
* @throws ZipException
*/
public function getEncryptionMethod()
{
return isset(self::$encryptionMethods[$this->getKeyStrength()]) ?
self::$encryptionMethods[$this->getKeyStrength()] :
self::$encryptionMethods[self::KEY_STRENGTH_256BIT];
}
/**
* @param int $encryptionMethod
* @return int
* @throws ZipException
*/
public static function getKeyStrangeFromEncryptionMethod($encryptionMethod)
{
$flipKey = array_flip(self::$encryptionMethods);
if (!isset($flipKey[$encryptionMethod])) {
throw new ZipException("Unsupport encryption method " . $encryptionMethod);
}
return $flipKey[$encryptionMethod];
}
/**
* Sets compression method.
*
* @param int $compressionMethod Compression method
* @throws ZipException Compression method out of range.
*/
public function setMethod($compressionMethod)
{
if (0x0000 > $compressionMethod || $compressionMethod > 0xffff) {
throw new ZipException('Compression method out of range');
}
$this->method = $compressionMethod;
}
/**
* Set key strength.
*
* @param int $keyStrength
*/
public function setKeyStrength($keyStrength)
{
$this->encryptionStrength = self::encryptionStrength($keyStrength);
}
/**
* Returns encryption strength.
*
* @param int $keyStrength Key strength in bits.
* @return int
*/
public static function encryptionStrength($keyStrength)
{
return isset(self::$keyStrengths[$keyStrength]) ?
self::$keyStrengths[$keyStrength] :
self::$keyStrengths[self::KEY_STRENGTH_128BIT];
}
/**
* Serializes a Data Block.
* @return string
*/
public function serialize()
{
return pack(
'vvcv',
$this->vendorVersion,
self::VENDOR_ID,
$this->encryptionStrength,
$this->method
);
}
/**
* Initializes this Extra Field by deserializing a Data Block.
* @param string $data
* @throws ZipException
*/
public function deserialize($data)
{
$size = strlen($data);
if (self::DATA_SIZE !== $size) {
throw new ZipException('WinZip AES Extra data invalid size: ' . $size . '. Must be ' . self::DATA_SIZE);
}
/**
* @var int $vendorVersion
* @var int $vendorId
* @var int $keyStrength
* @var int $method
*/
$unpack = unpack('vvendorVersion/vvendorId/ckeyStrength/vmethod', $data);
$this->setVendorVersion($unpack['vendorVersion']);
if (self::VENDOR_ID !== $unpack['vendorId']) {
throw new ZipException('Vendor id invalid: ' . $unpack['vendorId'] . '. Must be ' . self::VENDOR_ID);
}
$this->setKeyStrength(self::keyStrength($unpack['keyStrength'])); // checked
$this->setMethod($unpack['method']);
}
}