EDIT: DO NOT USE THIS IT IS INSECURE
I have used this in the past, i think i originally found it here on stackoverflow somewhere.
class EncryptClass
{
private $crypt_password;# = 'SOME PASSWORD';
private $crypt_salt = 'SOME SALT';
public function password($pWord)
{
$this->crypt_password = $pWord;
return true;
}
public function encrypt($decrypted)
{
$pass = $this->crypt_password;
$salt = $this->crypt_salt;
// Build a 256-bit $key which is a SHA256 hash of $salt and $password.
$key = hash('SHA256', $salt . $pass, true);
// Build $iv and $iv_base64. We use a block size of 128 bits (AES compliant) and CBC mode. (Note: ECB mode is inadequate as IV is not used.)
srand(); $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC), MCRYPT_RAND);
if (strlen($iv_base64 = rtrim(base64_encode($iv), '=')) != 22) return false;
// Encrypt $decrypted and an MD5 of $decrypted using $key. MD5 is fine to use here because it's just to verify successful decryption.
$encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $decrypted . md5($decrypted), MCRYPT_MODE_CBC, $iv));
// We're done!
return urlencode($iv_base64 . $encrypted);
}
public function decrypt($encrypted)
{
$pass = $this->crypt_password;
$salt = $this->crypt_salt;
$encrypted = rawurldecode($encrypted);
// Build a 256-bit $key which is a SHA256 hash of $salt and $password.
$key = hash('SHA256', $salt . $pass, true);
// Retrieve $iv which is the first 22 characters plus ==, base64_decoded.
$iv = base64_decode(substr($encrypted, 0, 22) . '==');
// Remove $iv from $encrypted.
$encrypted = substr($encrypted, 22);
// Decrypt the data. rtrim won't corrupt the data because the last 32 characters are the md5 hash; thus any \0 character has to be padding.
$decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($encrypted), MCRYPT_MODE_CBC, $iv), "\0\4");
// Retrieve $hash which is the last 32 characters of $decrypted.
$hash = substr($decrypted, -32);
// Remove the last 32 characters from $decrypted.
$decrypted = substr($decrypted, 0, -32);
// Integrity check. If this fails, either the data is corrupted, or the password/salt was incorrect.
if (md5($decrypted) != $hash) return false;
// Yay!
return $decrypted;
}
}//class crypt
Then use it like this:
$cr = new EncryptClass;
$cr->password('A PASSWORD');
// to encrypt
$crypt = $cr->encrypt('The thing you want to crypt');
// to decrypt
$decrypt = $cr->decrypt('The thing you want to decrypt');
Hope it helps.
