com.gwtcx.server.util.Security.java Source code

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Here is the source code for com.gwtcx.server.util.Security.java

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/**
 * (C) Copyright 2010, 2011 upTick Pty Ltd
 *
 * Licensed under the terms of the GNU General Public License version 3
 * as published by the Free Software Foundation. You may obtain a copy of the
 * License at: http://www.gnu.org/copyleft/gpl.html
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.gwtcx.server.util;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
//import java.security.SecureRandom;

import org.apache.commons.lang.RandomStringUtils;

// import com.allen_sauer.gwt.log.client.Log;

public class Security {

    public static String byteStringToHexString(final String s) {
        String r = "";
        for (int i = 0; i < s.length(); i++) {
            r += byteToHexChars(s.charAt(i));
        }
        return r;
    }

    public static String byteToHexChars(final int i) {
        final String s = "0" + Integer.toHexString(i);
        return s.substring(s.length() - 2);
    }

    public static String hexStringToByteString(final String s) {
        String r = "";
        for (int i = 0; i < s.length(); i += 2) {
            r += (char) Integer.parseInt(s.substring(i, i + 2), 16);
        }
        return r;
    }

    public static String md5(final String text) {
        String hashword = null;

        try {
            final MessageDigest md5 = MessageDigest.getInstance("MD5");
            md5.update(text.getBytes());
            final BigInteger hash = new BigInteger(1, md5.digest());
            hashword = hash.toString(16);
        } catch (final NoSuchAlgorithmException nsae) {
        }

        while (hashword.length() < 32) {
            hashword = "0" + hashword;
        }

        return hashword;
    }

    /**
     * Generates a string of 32 letters (A to Z)
     * 
     * @return A string formed by 32 A-to-Z random letters.
     */
    public static String randomCharString() {
        return RandomStringUtils.randomAlphabetic(32);
    }

    /*
        
    public static String randomCharString() {
      String buffer = null;
          
      Log.debug("randomCharString()");
        
      try {
        SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
        
        byte[] salt = new byte[32];
        secureRandom.nextBytes(salt);
        
        Log.debug("salt: " + salt);
        
        buffer = new String(salt);
      }
      catch (NoSuchAlgorithmException e) {
      }
        
      Log.debug("buffer: " + buffer);
        
      return buffer;
    }
        
    */

    private final byte sbox[] = new byte[256];
    private int i;
    private int j;

    public String codeDecode(final String plaintext) {
        byte x;
        String r = "";
        final int pl = plaintext.length();
        for (int k = 0; k < pl; k++) {
            i = i + 1 & 0xff;
            j = j + sbox[i] & 0xff;

            x = sbox[i];
            sbox[i] = sbox[j];
            sbox[j] = x;

            r += (char) (plaintext.charAt(k) ^ sbox[sbox[i] + sbox[j] & 0xff] & 0xff);
        }

        return r;
    }

    public String codeDecode(final String key, final String plaintext) {
        setUp(key);
        return codeDecode(plaintext);
    }

    public void setUp(final String key) {
        int k;
        byte x;

        for (i = 0; i < 256; i++) {
            sbox[i] = (byte) i;
        }

        final int kl = key.length();
        for (i = 0, j = 0, k = 0; i < 256; i++) {
            j = j + sbox[i] + key.charAt(k) & 0xff;
            k = (k + 1) % kl;

            x = sbox[i];
            sbox[i] = sbox[j];
            sbox[j] = x;
        }

        // Set things up to start coding/decoding

        i = 0;
        j = 0;
    }
}