<?php
namespace Illuminate\Encryption;
use Illuminate\Contracts\Encryption\DecryptException;
use Illuminate\Contracts\Encryption\Encrypter as EncrypterContract;
use Illuminate\Contracts\Encryption\EncryptException;
use Illuminate\Contracts\Encryption\StringEncrypter;
use RuntimeException;
class Encrypter implements EncrypterContract, StringEncrypter
{
/**
* The encryption key.
*
* @var string
*/
protected $key;
/**
* The algorithm used for encryption.
*
* @var string
*/
protected $cipher;
/**
* Create a new encrypter instance.
*
* @param string $key
* @param string $cipher
* @return void
*
* @throws \RuntimeException
*/
public function __construct($key, $cipher = 'AES-128-CBC')
{
$key = (string) $key;
if (static::supported($key, $cipher)) {
$this->key = $key;
$this->cipher = $cipher;
} else {
throw new RuntimeException('The only supported ciphers are AES-128-CBC and AES-256-CBC with the correct key lengths.');
}
}
/**
* Determine if the given key and cipher combination is valid.
*
* @param string $key
* @param string $cipher
* @return bool
*/
public static function supported($key, $cipher)
{
$length = mb_strlen($key, '8bit');
return ($cipher === 'AES-128-CBC' && $length === 16) ||
($cipher === 'AES-256-CBC' && $length === 32);
}
/**
* Create a new encryption key for the given cipher.
*
* @param string $cipher
* @return string
*/
public static function generateKey($cipher)
{
return random_bytes($cipher === 'AES-128-CBC' ? 16 : 32);
}
/**
* Encrypt the given value.
*
* @param mixed $value
* @param bool $serialize
* @return string
*
* @throws \Illuminate\Contracts\Encryption\EncryptException
*/
public function encrypt($value, $serialize = true)
{
$iv = random_bytes(openssl_cipher_iv_length($this->cipher));
// First we will encrypt the value using OpenSSL. After this is encrypted we
// will proceed to calculating a MAC for the encrypted value so that this
// value can be verified later as not having been changed by the users.
$value = \openssl_encrypt(
$serialize ? serialize($value) : $value,
$this->cipher, $this->key, 0, $iv
);
if ($value === false) {
throw new EncryptException('Could not encrypt the data.');
}
// Once we get the encrypted value we'll go ahead and base64_encode the input
// vector and create the MAC for the encrypted value so we can then verify
// its authenticity. Then, we'll JSON the data into the "payload" array.
$mac = $this->hash($iv = base64_encode($iv), $value);
$json = json_encode(compact('iv', 'value', 'mac'), JSON_UNESCAPED_SLASHES);
if (json_last_error() !== JSON_ERROR_NONE) {
throw new EncryptException('Could not encrypt the data.');
}
return base64_encode($json);
}
/**
* Encrypt a string without serialization.
*
* @param string $value
* @return string
*
* @throws \Illuminate\Contracts\Encryption\EncryptException
*/
public function encryptString($value)
{
return $this->encrypt($value, false);
}
/**
* Decrypt the given value.
*
* @param string $payload
* @param bool $unserialize
* @return mixed
*
* @throws \Illuminate\Contracts\Encryption\DecryptException
*/
public function decrypt($payload, $unserialize = true)
{
$payload = $this->getJsonPayload($payload);
$iv = base64_decode($payload['iv']);
// Here we will decrypt the value. If we are able to successfully decrypt it
// we will then unserialize it and return it out to the caller. If we are
// unable to decrypt this value we will throw out an exception message.
$decrypted = \openssl_decrypt(
$payload['value'], $this->cipher, $this->key, 0, $iv
);
if ($decrypted === false) {
throw new DecryptException('Could not decrypt the data.');
}
return $unserialize ? unserialize($decrypted) : $decrypted;
}
/**
* Decrypt the given string without unserialization.
*
* @param string $payload
* @return string
*
* @throws \Illuminate\Contracts\Encryption\DecryptException
*/
public function decryptString($payload)
{
return $this->decrypt($payload, false);
}
/**
* Create a MAC for the given value.
*
* @param string $iv
* @param mixed $value
* @return string
*/
protected function hash($iv, $value)
{
return hash_hmac('sha256', $iv.$value, $this->key);
}
/**
* Get the JSON array from the given payload.
*
* @param string $payload
* @return array
*
* @throws \Illuminate\Contracts\Encryption\DecryptException
*/
protected function getJsonPayload($payload)
{
$payload = json_decode(base64_decode($payload), true);
// If the payload is not valid JSON or does not have the proper keys set we will
// assume it is invalid and bail out of the routine since we will not be able
// to decrypt the given value. We'll also check the MAC for this encryption.
if (! $this->validPayload($payload)) {
throw new DecryptException('The payload is invalid.');
}
if (! $this->validMac($payload)) {
throw new DecryptException('The MAC is invalid.');
}
return $payload;
}
/**
* Verify that the encryption payload is valid.
*
* @param mixed $payload
* @return bool
*/
protected function validPayload($payload)
{
return is_array($payload) && isset($payload['iv'], $payload['value'], $payload['mac']) &&
strlen(base64_decode($payload['iv'], true)) === openssl_cipher_iv_length($this->cipher);
}
/**
* Determine if the MAC for the given payload is valid.
*
* @param array $payload
* @return bool
*/
protected function validMac(array $payload)
{
return hash_equals(
$this->hash($payload['iv'], $payload['value']), $payload['mac']
);
}
/**
* Get the encryption key.
*
* @return string
*/
public function getKey()
{
return $this->key;
}
}