C# Rijndael IV size doesn't match block size, while it should

Question

I have the following code:

private void EncryptFile(string inputFile, string outputFile, string pass)
    {
        try
        {
            string password = @pass;
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] key = UE.GetBytes(password);
            byte[] iv = new byte[128];
            for(int i =0; i < iv.Length; i++)
            {
                iv[i] = Convert.ToByte(true);
            }
            string cryptFile = outputFile;
            FileStream fsCrypt = new FileStream(cryptFile, FileMode.Create);

            RijndaelManaged RMCrypto = new RijndaelManaged();
            MessageBox.Show(RMCrypto.BlockSize + "\n" + iv.Length);
            CryptoStream cs = new CryptoStream(fsCrypt,
                RMCrypto.CreateEncryptor(key, iv),
                CryptoStreamMode.Write);

            FileStream fsIn = new FileStream(inputFile, FileMode.Open);

            int data;
            while ((data = fsIn.ReadByte()) != -1)
                cs.WriteByte((byte)data);


            fsIn.Close();
            cs.Close();
            fsCrypt.Close();
        }
        catch(Exception ex)
        {
            //MessageBox.Show("Encryption failed!", "Error");
            MessageBox.Show(ex.Message);
        }
    }

But have a problem with the IV size. Using a simple message box I found that (probably) the block size is 128. So, I set the IV to a 128 bytes array full of "1" values to test. The first message box confirms the blocksize and the IV array length are both 128. However, I get an exception saying Specified initialization vector (IV) does not match the block size for this algorithm.

Why is this and how to fix the issue?

Answer 1

AES block size is 128 bits . Not bytes. Bits.

The winner of the AES contest, Rijndael, supports block and key sizes of 128, 192, and 256 bits , but in AES the block size is always 128 bits . The extra block sizes were not adopted by the AES standard