Hello guys,

I need to implement FEAL Cipher in JAVA. The main idea is to make a console program which encrypts .txt file into an FEAL cipher encrypted file. Later on, the same program should be able to decrypt the encrypted file back into .txt format.

I have to write the cipher using the DES S-boxes defined in page 38 in here: http://cacr.uwaterloo.ca/hac/about/chap7.pdf

The implementation of the cipher is described here: http://info.isl.ntt.co.jp/crypt/eng/...al/call-3e.pdf

And the example of the cipher in C language can be found here (not sure if that's exactly what I need): http://info.isl.ntt.co.jp/crypt/eng/...eal/call-6.txt

I have also found this implementation of FEAL cipher in Java, but it uses a lot of packages and libraries what is not really good for me. I only need to make it use the main JAVA libraries:

My problem is that the steps of the implementation are not really clear to me.

Not sure what to do with the text when I get it from the file. How do I divide it into two 32-bit parts (Left and Right)? Do I just convert the text into string of bytes and take first 4 bits of the every character to the left part and last 4 bits to the right part? If yes, what after should I do exactly?

If anyone has any experience with similar algorithms or has an idea how to implement this, I would really appreciate your help.

Fellow programmer ElJay