Input byte array has incorrect ending byte at 40

Question

I have a string that is base64 encoded. It looks like this:

eyJibGExIjoiYmxhMSIsImJsYTIiOiJibGEyIn0=

Any online tool can decode this to the proper string which is {"bla1":"bla1","bla2":"bla2"}. However, my Java implementation fails:

import java.util.Base64;
System.out.println("payload = " + payload);
String json = new String(Base64.getDecoder().decode(payload));

I'm getting the following error:

payload = eyJibGExIjoiYmxhMSIsImJsYTIiOiJibGEyIn0=
java.lang.IllegalArgumentException: Input byte array has incorrect ending byte at 40

What is wrong with my code?

Answer 1

Okay, I found out. The original String is encoded on an Android device using android.util.Base64 by Base64.encodeToString(json.getBytes("UTF-8"), Base64.DEFAULT);. It uses android.util.Base64.DEFAULT encoding scheme.

Then on the server side when using java.util.Base64 this has to be decoded with Base64.getMimeDecoder().decode(payload) not with Base64.getDecoder().decode(payload)

Answer 2

I was trying to use the strings from the args. I found that if I use arg[0].trim() that it made it work. eg

Base64.getDecoder().decode(arg[0].trim());

I guess there's some sort of whitespace that gets it messed up.

Answer 3

Maybe too late, but I also had this problem.

By default, the Android Base64 util adds a newline character to the end of the encoded string.
The Base64.NO_WRAP flag tells the util to create the encoded string without the newline character.

Your android app should encode src something like this:

String encode = Base64.encodeToString(src.getBytes(), Base64.NO_WRAP);