How to include md5 package in application

Question

Hi All,
First of all sorry I posted in another users thread. In the thread http://forums.sun.com/thread.jspa?threadID=5426671 the person used org.bouncycastle.crypto.digests.MD5Digest for doing md5.
I need some help here on how you include the org.bouncycastle.crypto.digests.MD5Digest library in my java code as I want to use the md5.
I am also working on something similar like that but without the web application part and a detail which consists on OTP part using md5.
As the md5() doesn't work in j2me so was also searching for something which will work on MIDP.
package com.abc; //package define
public class messDig5 //class define
    private String generateHash(String OTP, int loopNum) {
        byte[] secretBytes = OTP.getBytes();
        for (int x = 0; x < loopNum; x++) {
            byte[] tempStore = new byte[16];
            tempStore = hash(secretBytes);
            secretBytes = tempStore;
     //   return convertToHex(secretBytes);
        return byteArrayToHexString(secretBytes);
    public byte[] hash(byte[] secretBytes) {
       org.bouncycastle.crypto.digests.MD5Digest digest = new org.bouncycastle.crypto.digests.MD5Digest();
        digest.reset();
        // Update MD5 digest with user secret in byte format
        digest.update(secretBytes, 0, secretBytes.length);
        // get length of digest to initialise new md5 byte array
        int length = digest.getDigestSize();
        // create md5 byte array using length
        byte[] md5 = new byte[length];
        // calculate MD5 hash, using md5 byte array, 0 for buffer offset
        digest.doFinal(md5, 0);
        return md5;
//    private static String convertToHex(byte[] data) {
//        StringBuffer buf = new StringBuffer();
//        String Hex;
//        String formattedHex;
//        for (int i = 0; i < data.length; i++) {
//            int halfbyte = (data[i] >>> 4) & 0x0F;
//            int two_halfs = 0;
//            do {
//                if ((0 <= halfbyte) && (halfbyte <= 9)) {
//                    buf.append((char) ('0' + halfbyte));
//                } else {
//                    buf.append((char) ('a' + (halfbyte - 10)));
//                halfbyte = data[i] & 0x0F;
//            } while (two_halfs++ < 1);
//        Hex = buf.toString();
//        formattedHex = "\n" + Hex.substring(0, 4) + " " + Hex.substring(4, 8) + " " + Hex.substring(8, 12) + " " + Hex.substring(12, 16) + " " + Hex.substring(16, 20) + " " + Hex.substring(20, 24) + " " + Hex.substring(24, 28) + " " + Hex.substring(28, 32);
//        return formattedHex;
    static String byteArrayToHexString(byte byteValues[]) {
        byte singleChar = 0;
        if (byteValues == null || byteValues.length <= 0) {
            return null;
        String entries[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
            "a", "b", "c", "d", "e", "f"};
        StringBuffer out = new StringBuffer(byteValues.length * 2);
        for (int i = 0; i < byteValues.length; i++) {
            singleChar = (byte) (byteValues[i] & 0xF0);
            singleChar = (byte) (singleChar >>> 4);
            // shift the bits down
            singleChar = (byte) (singleChar & 0x0F);
            out.append(entries[(int) singleChar]);
            singleChar = (byte) (byteValues[i] & 0x0F);
            out.append(entries[(int) singleChar]);
        String rslt = new String(out);
        return rslt;

Answer 1

Camellia,
I take you already added bouncycatsle to your project as a compile dependency, since it compiles (unless it does not).
All you have to do for your code to work on the phone, you need to build your JAR file (that you use to distribute your MIDlet) with bouncycastle packaged in. This will all depend on the method you use to build your JAD and JAR files.
I use antenna tool, which provides me with ant tasks to compile, build jar, package external libraries etc. Your scenario can be different, but all you have to do is to search manuals and/or google for methods on how to package external libraries with your build.
Daniel