Question

i know there is many types of encode and decode and from what i have read, base64 is a great choice when it comes to encode binary file (image, mp3, video).

Now, when it comes to decode, i will need to convert from the base64 and then get the string value. the process to get the string after decode, i will require to do like this (in c#): System.Text.Encoding.ASCII.GetString(encodedDataAsBytes);

here i noticed that i have several choices on what to use to get the string, such as ASCII, UNICODE, DEFAULT.

the real question in this post is if im using java to encode and c# to decode the binary file, what is the best solution/choice should i use? i have tried several method and some of the character could not be read thus gives out question mark symbol (?).

however, the most closer encode decode that could be read the byte is when im using this in Java: String encoded = Base64.encodeToString(fileData, Base64.CRLF); meanwhile in c# im using like this: byte[] encodedDataAsBytes = System.Convert.FromBase64String(encodedData);
string returnValue = System.Text.Encoding.ASCII.GetString(encodedDataAsBytes);

Still, there are several character that cannot be read. Does anyone have solution for this problem statement? any feedback is much appreciated. thanks for advance.

Answer 1

You state that that input is “image, mp3, video”, so: arbitrary binary. You then state that you’re using base-64, meaning: for some reason you need to transfer / store this data as a string (note: transfer / storage as raw binary would usually be preferred – base-64 has overhead).

Now, when it comes to decode, i will need to convert from the base64 and then get the string value.

There’s the problem; there is no string value here. An “image, mp3, video” is simply not a “string value”. What you can do is decode from the base-64 back to raw binary (trivial in either java or c#), but that is all you can do. If you needed a “string value” from raw binary, the only thing you can do is to re-encode it via base-64 (which would give you back what you started with), or some other base-n.

A text-encoding such as ASCII or UTF-8 only makes sense if the binary data is known to actually be text data stored in that encoding. You cannot use UTF-8 to “decode” binary that isn’t actually UTF-8.