php - mcrypt_decrypt(): IV パラメータは、ブロックサイズと同じ長さでなければなりません

Question

コード内の一部の情報を暗号化しようとしているので、これを行う方法を探しました。これはphpの公式ウェブサイトで見つけました： http://www.php.net/manual/vote-note.php?id=107483&page=book.mcrypt&vote=down

だから、私はそれを少し変えて、これをしました：

class EncrypterDecrypter {

private $SECRET = "xxxxxxxxxxxxxxxxxxxx";


function encrypt($decrypted, $salt = 'zzzzzzzzzzzzzzzzzz') {
    $password = $this->SECRET;
    // 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;
}

public function decrypt($encrypted, $salt = 'zzzzzzzzzzzzzzzzzz') {
    $password = $this->SECRET;
    // 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;
   }
}

キーとソルトのサイズを変更しようとしましたが、警告が表示され続けます。他のトピックも検索しましたが、答えが見つかりませんでした。すべて特定のものに見えます。