Функция шифрует строку, но расшифровать не получается. Подскажите где ошибка.

function encrypt($decrypted, $password="123", $salt='!kQm*fF3pXe1Kbm%9') {
// Build a 256-bit $key which is a SHA256 hash of $salt and $password.
$key = hash('SHA256', $salt . $password, 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 $iv_base64 . $encrypted;
}
 
 
function decrypt($encrypted, $password="123", $salt='!kQm*fF3pXe1Kbm%9') {
// Build a 256-bit $key which is a SHA256 hash of $salt and $password.
$key = hash('SHA256', $salt . $password, 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;
}
 
$a = base64_encode(encrypt("rus"));
print $a;
 
print base64_encode(decrypt($a));  // здесь строка не расшифровывается