<?php
declare(strict_types=1);
namespace ParagonIE\Paserk\Types;
use ParagonIE\ConstantTime\{
Base64UrlSafe,
Binary
};
use ParagonIE\Paserk\{
ConstraintTrait,
PaserkException,
PaserkTypeInterface,
Util
};
use ParagonIE\Paseto\{
Exception\InvalidVersionException,
KeyInterface,
Keys\SymmetricKey,
ProtocolCollection,
ProtocolInterface
};
use SodiumException;
use function
count,
explode,
implode;
/**
* Class Local
* @package ParagonIE\Paserk\Types
*/
class Local implements PaserkTypeInterface
{
use ConstraintTrait;
/**
* @throws InvalidVersionException
*/
public function __construct(ProtocolInterface ...$versions) {
if (count($versions) > 0) {
$this->collection = new ProtocolCollection(...$versions);
} else {
$this->collection = ProtocolCollection::v4();
}
}
/**
* @param KeyInterface $key
* @return string
*
* @throws PaserkException
*/
public function encode(KeyInterface $key): string
{
if (!($key instanceof SymmetricKey)) {
throw new PaserkException('Only symmetric keys can be serialized as kx.local.');
}
$this->throwIfInvalidProtocol($key->getProtocol());
/// @SPEC DETAIL: Algorithm Lucidity
if (Binary::safeStrlen($key->raw()) < 32) {
throw new PaserkException("Symmetric keys must be 256-bit");
}
$version = Util::getPaserkHeader($key->getProtocol());
return implode('.', [$version, self::getTypeLabel(), $key->encode()]);
}
/**
* @param string $paserk
* @return KeyInterface
*
* @throws PaserkException
*/
public function decode(string $paserk): KeyInterface
{
$pieces = explode('.', $paserk);
if (count($pieces) !== 3) {
throw new PaserkException('Invalid PASERK');
}
if (!hash_equals(self::getTypeLabel(), $pieces[1])) {
throw new PaserkException('Invalid PASERK');
}
$version = Util::getPasetoVersion($pieces[0]);
$this->throwIfInvalidProtocol($version);
/// @SPEC DETAIL: Algorithm Lucidity
$decoded = Base64UrlSafe::decode($pieces[2]);
if (Binary::safeStrlen($decoded) < 32) {
throw new PaserkException("Symmetric keys must be 256-bit");
}
return new SymmetricKey(
$decoded,
$version
);
}
/**
* @return string
*/
public static function getTypeLabel(): string
{
return 'local';
}
/**
* Get the lid PASERK for the PASERK representation of this local key.
*
* @param KeyInterface $key
* @return string
* @throws PaserkException
* @throws SodiumException
*/
public function id(KeyInterface $key): string
{
return Lid::encode(
$key->getProtocol(),
$this->encode($key)
);
}
}
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