byte[] to String and String to byte[]

Question

I have a small problem to change the type from byte[] to String and then from String to byte[]. When I use my code, it returns the RSA error "Too much data for rsa block". But when I use the original byte[], it works fine.

This is how it works:

cipherData = cipher.doFinal(cipherData);

I tried to change the data type:

// Byte[] to String
String encrypted = new String(cipherData, "UTF-8");
// RSA Operation
cipherData = cipher.doFinal(encrypted.getBytes());

I don't understand. The line String encrypted = new String(cipherData, "UTF-8") is not going to have any effect on the line cipherData = cipher.doFinal(cipherData). — John Kugelman
– John Kugelman, Commented Apr 4, 2013 at 16:52
You are absolutely right. Changed it. But the error persists. I tried it also with StringBuffer. It does not work as well. — JavaForAndroid
– JavaForAndroid, Commented Apr 4, 2013 at 16:55
Have you tried specifying character set explicitly: encrypted.getBytes("UTF-8") ? — PM 77-1
– PM 77-1, Commented Apr 4, 2013 at 17:07

Jon Skeet · Accepted Answer · 2013-04-04 17:23:14Z

7

This is the problem:

String encrypted = new String(cipherData, "UTF-8");

Your cipherData isn't UTF-8-encoded text. It's arbitrary binary data. So don't try to interpret it as if it were UTF-8 text.

Instead, use either hex or base64 - where base64 is probably the simplest approach. I like the public domain iHarder base64 library:

String encrypted = Base64.encodeBytes(cipherData);
...

cipherData = Base64.decode(encrypted);

EDIT: If you're using Android of course, then use the built-in library :)

edited Apr 4, 2013 at 17:23

answered Apr 4, 2013 at 16:58

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

MrMoDoJoJr Over a year ago

Why would you use iHarder and not the built in support of the Convert class?

JavaForAndroid Over a year ago

If I would like to use such a library, i have to take a look at Android Base64 libraries. Does the library also support decryption?

JavaForAndroid Over a year ago

Thanks. I will check the API for Base64 on Android.

Jon Skeet Over a year ago

@MrMoDoJoJr: Are you thinking of System.Convert in .NET? This is Java.

JavaForAndroid · Accepted Answer · 2013-04-04 17:09:28Z

0

I works perfect. Here is the Code for Android Base64 library:

String encrypted = Base64.encodeToString(cipherData, Base64.DEFAULT);
cipherData = cipher.doFinal(Base64.decode(encrypted, Base64.DEFAULT));

answered Apr 4, 2013 at 17:09

JavaForAndroid

1,1792 gold badges22 silver badges47 bronze badges

Collectives™ on Stack Overflow

byte[] to String and String to byte[]

2 Answers 2

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related