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Olivier Ligny - - 12/03/2008 - vue 7062 fois

DES 256 bits encrypter/decrypter - Java source code

A java class to encrypt/decrypt data using 96 bits DES algorithm.

Usage :

String encrypted = DesEncrypter.cryptString("hello world", "ABCDEFABCDEFABCDEFABCDEF");
String plain = DesEncrypter.decryptString(encrypted, "ABCDEFABCDEFABCDEFABCDEF");

The key is a 24 hex string (= 12 bytes = 96 bits)
This class uses the javax.crypto extensions, you must have it in your classpath.


import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;
import com.sun.crypto.provider.SunJCE;
import java.security.spec.*;

import java.util.Date;


public class DesEncrypter {
    Cipher ecipher;
    Cipher dcipher;

    // 8-byte Salt
    static byte[] salt = {
        (byte)0xA9, (byte)0x9B, (byte)0xC8, (byte)0x32,
        (byte)0x56, (byte)0x35, (byte)0xE3, (byte)0x03
    };

    // Iteration count
    static int iterationCount = 19;

    public static String cryptString(String str, String key) {
        String encrypted = "";
        try {
            DesEncrypter encrypter = new DesEncrypter(key);
            encrypted = encrypter.encrypt(str);
        } catch (Exception e) {
            System.out.println(e);
            e.printStackTrace();
        }
        return encrypted;       
    }

    public static String decryptString(String str, String key) {
        String decrypted = "";
        try {
            DesEncrypter encrypter = new DesEncrypter(key);
            decrypted = encrypter.decrypt(str);
        } catch (Exception e) {
            System.out.println(e);
            e.printStackTrace();
        }
        return decrypted;       
    }

    DesEncrypter(String passPhrase) {
        try {
            // Create the key
            KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
            SecretKey key = SecretKeyFactory.getInstance(
                "PBEWithMD5AndDES").generateSecret(keySpec);
            ecipher = Cipher.getInstance(key.getAlgorithm());
            dcipher = Cipher.getInstance(key.getAlgorithm());

            // Prepare the parameter to the ciphers
            AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);

            // Create the ciphers
            ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
            dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
        } catch (java.security.InvalidAlgorithmParameterException e) {
        } catch (java.security.spec.InvalidKeySpecException e) {
        } catch (javax.crypto.NoSuchPaddingException e) {
        } catch (java.security.NoSuchAlgorithmException e) {
        } catch (java.security.InvalidKeyException e) {
        }
   }

    public String byteArrayToString(byte[] data) {
        String res = "";
        StringBuffer sb = new StringBuffer();
        for(int i=0; i<data.length; i++) {
            int n = (int) data[i];
            if(n<0) n += 256;
            sb.append((char) n);
        }
        res = sb.toString();
        return res;
    }
   
    public byte[] stringToByteArray(String s){
        byte[] temp = new byte[s.length()];
        for(int i=0;i<s.length();i++){
            temp[i] = (byte) s.charAt(i);
        }
        return temp;
    }

    public String encrypt(String str) {
        try {
            // Encode the string into bytes using utf-8
            byte[] utf8 = str.getBytes("UTF8");

            // Encrypt
            byte[] enc = ecipher.doFinal(utf8);

            return byteArrayToString(enc);
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (java.io.IOException e) {
        }
        return null;
    }

    public String decrypt(String str) {
        try {

            byte[] dec = stringToByteArray(str);

            // Decrypt
            byte[] utf8 = dcipher.doFinal(dec);

            // Decode using utf-8
            return new String(utf8, "UTF8");
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (java.io.IOException e) {
        }
        return null;
    }
   
   
   
    public static void main(String[] args) {
       
       
    }
   
     public static String static_intArrayToString(int[]t){
        StringBuffer sb = new StringBuffer();
        for(int i=0;i<t.length;i++){
            sb.append((char)t[i]);
        }
        return sb.toString();
    }
  
}




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