Question

I have the following code. When I check the value of variable i it is 16 bytes but then when the output is converted to Base64 it is 24 bytes.

   byte[] bytOut = ms.GetBuffer();
        int i = 0;
        for (i = 0; i < bytOut.Length; i++)
            if (bytOut[i] == 0)
                break;

        // convert into Base64 so that the result can be used in xml

        return System.Convert.ToBase64String(bytOut, 0, i);

Is this expected? I am trying to cut down storage and this is one of my problems.

Answer 1

Yes, you’d expect to see some expansion. You’re representing your data in a base with only 64 characters. All those unprintable ASCII characters still need a way to be encoded though. So you end up with slight expansion of the data.

Here’s a link that explains how much: Base64: What is the worst possible increase in space usage?

Edit: Based on your comment above, if you need to reduce size, you should look at compressing the data before you encrypt. This will get you the max benefit from compression. Compressing encrypted binary does not work.