Hi,

I have a problem with my decryption, the encryption seems to work fine but
when I try to decrypt the encrypted string I get an exception "Padding is
invalid and cannot be removed." thrown on sreader.ReadToEnd(); so could
anyone tell me what I'm doing wrong?

public class MyRijndael
{
    private byte[] _iv;
    public MyRijndael(byte[] iv)
    {
        this._iv = iv;
    }

    public string Encrypt(string input, byte[] key)
    {
        MemoryStream output = new MemoryStream();

        Rijndael rn = Rijndael.Create();

        CryptoStream scrypt = new CryptoStream(output,
rn.CreateEncryptor(key, this._iv), CryptoStreamMode.Write);
        scrypt.FlushFinalBlock();

        StreamWriter swriter = new StreamWriter(scrypt);
        swriter.Write(input);
        swriter.Flush();

        byte[] buffer = output.ToArray();

        swriter.Close();
        scrypt.Close();
        output.Close();

        return Convert.ToBase64String(buffer);
    }

    public string Decrypt(string input64, byte[] key)
    {
        MemoryStream input = new
MemoryStream(Convert.FromBase64String(input64));

        Rijndael rn = Rijndael.Create();

        CryptoStream scrypt = new CryptoStream(input,
rn.CreateDecryptor(key, this._iv), CryptoStreamMode.Read);

        StreamReader sreader = new StreamReader(scrypt);

        string res = sreader.ReadToEnd();    <-- error "Padding is invalid
and cannot be removed."

        sreader.Close();
        scrypt.Close();
        input.Close();

        return res;
    }
}

Show quote Hide quote Sure - you're calling FlushFinalBlock before you've written anything to the
stream.  You are supposed to write everything to the stream, then call
FlushFinalBlock, then close the stream.

Alun.
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