Question

I am converting a byte[] array to string . And then converting the string back to byte[] array. Then on checking if both the arrays are equal – I get that they are not equal:

 byte[] ciphertext2=c.doFinal(username.getBytes("utf-8"));
          //JUST CHECKING IGNORE
          String qaz=new String(ciphertext2,"utf-8");
          //qaz=qaz+"1";
          System.out.println("just chekcing------------------------"+qaz);
          byte[] ciphertext3=qaz.getBytes("utf-8");
          if(Arrays.equals(ciphertext2,ciphertext3))
          {
           System.out.println("just chekcing they are equal------------------------");
          }
          else
          System.out.println("just chekcing they are not equal------------------------");<br>

OUTPUT :

just chekcing they are not equal-------------------- 

Why doesn’t it work?
Edit

It works perfectly fine when using Base64 of java. But why doesn’t it work when converting byte to string and vice-versa directly? What actually happens when you convert a string a byte array and vice versa?

Answer 1

If this is the result of encryption, you should not be using a string constructor. You don’t have encoded text – you have arbitrary binary data. You need to understand the difference between data which is fundamentally text and which needs to be represented in binary (e.g. writing a text file to disk) and data which is fundamentally binary and which needs to be represented in text (e.g. including encrypted data in an XML document).

You should use base64 (e.g. with this public domain library) or possibly hex. This will result in ASCII data which is guaranteed to roundtrip to the original binary data.