How to encypt a .txt file and how to decrypt a same .txt file when i need

Question

My requirement is i want to encrypt a .txt file and
keep it in some folder. In that file we put database connection
information. when ever we need that file we have to access it and decrypt
it. with that decrypted values we have make connection with database.
i am sending a code in which i wrote both encyption and decrytion in same file, but i want to do it separately.
Please help me regarding this.
package com.businessobjects;
import java.io.*;
import java.security.*;
import javax.crypto.*;
public class EncryptDecrypt
     public static void EncodeIt()
          try
          // generate Cipher objects for encoding and decoding
          Cipher itsocipher1 = Cipher.getInstance("DES");
          Cipher itsocipher2 = Cipher.getInstance("DES");
          // generate a KeyGenerator object
          KeyGenerator KG = KeyGenerator.getInstance("DES");
          System.out.println("Using algorithm " + KG.getAlgorithm());
          // generate a DES key
          Key mykey = KG.generateKey();
          // initialize the Cipher objects
          System.out.println("Initializing ciphers...");
          itsocipher1.init(Cipher.ENCRYPT_MODE, mykey);
          itsocipher2.init(Cipher.DECRYPT_MODE, mykey);
          // creating the encrypting cipher stream
          //System.out.println("Creating the encrypting cipher stream...");
          /*FileInputStream fis = new FileInputStream("Original.txt");
FileOutputStream fos = new FileOutputStream("Encypt.txt");
          CipherInputStream cis1 = new CipherInputStream(fis, itsocipher1);
          // creating the decrypting cipher stream
          //System.out.println("Creating the decrypting cipher stream...");
          byte[] b1 = new byte[8];
int i1 = cis1.read(b1);
          while (i1 != -1)
               fos.write(b1, 0, i1);
               i1 = cis1.read(b1);
fis.close();
fos.close();*/
// writing the decrypted data to output file
FileInputStream fis1 = new FileInputStream("Encypt.txt");
FileOutputStream fos1 = new FileOutputStream(Decypt.txt");
CipherInputStream cis2 = new CipherInputStream(fis1, itsocipher2);
          byte[] b2 = new byte[8];
          int i2 = cis2.read(b2);
          while (i2 != -1)
               fos1.write(b2, 0, i2);
               i2 = cis2.read(b2);
fis1.close();
          fos1.close();
//cis1.close();
          cis2.close();
          catch (Exception e)
          System.out.println("Caught exception: " + e);
With regards
Pavankumar.

Answer 1

here is the solution you wanted it
uses password based encryption
but your requirements are for very badly
designed code
This is the encryption part
it converts the inputfile original.txt
into the outputfile encrypt.txt which
contains the original encrypted
import java.io.FileInputStream;
import java.io.FileOutputStream;
import javax.crypto.Cipher;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
public class PWBEncryption {
    // Salt
    static byte[] salt = {
        (byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
        (byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
    // Iteration count
    static int count = 20;
    public PWBEncryption() {
    // params:
    // password   -> the pasword used to create the key
    // inputfile  -> the file containing the stuff to be encrypted
    // i.e. original.txt
    // outputfile -> the file that will contain the encrypted stuff
    // i.e. encrypt.txt
    public static boolean doIt(char[] password,String inputfile,String outputfile){
        try{
            // Create PBE parameter set
            PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, count);
            PBEKeySpec pbeKeySpec = new PBEKeySpec(password);
            // create secretkey
            SecretKeyFactory keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
            SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
            // create cipher
            Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
            pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
            // read input
            FileInputStream fis = new FileInputStream(inputfile);
            byte[] input = new byte[fis.available()];
            fis.read(input);
            // encrypt
            byte[] output = pbeCipher.doFinal(input);
            // write encrypted output
            FileOutputStream fos = new FileOutputStream(outputfile);
            fos.write(output);
            return true;
        catch(Exception e){
            System.out.println(e.toString());
            return false;
}This is the decrypt part
import java.io.FileInputStream;
import java.io.FileOutputStream;
import javax.crypto.Cipher;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
public class PWBDecryption {
    // Salt
    static byte[] salt = {
        (byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
        (byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
    // Iteration count
    static int count = 20;
    public PWBDecryption() {
    // params:
    // password   -> the pasword used to create the key
    // inputfile  -> the file containing the decrypted data
    // i.e. encrypt.txt
    // outputfile -> the file that will contain the decrypted data
    // i.e. decrypt.txt
    public static boolean doIt(char[] password,String inputfile,String outputfile){
        try{
            // Create PBE parameter set
            PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, count);
            PBEKeySpec pbeKeySpec = new PBEKeySpec(password);
            // create secretkey
            SecretKeyFactory keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
            SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
            // create cipher
            Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
            pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);
            // read input
            FileInputStream fis = new FileInputStream(inputfile);
            byte[] input = new byte[fis.available()];
            fis.read(input);
            // encrypt
            byte[] output = pbeCipher.doFinal(input);
            // write encrypted output
            FileOutputStream fos = new FileOutputStream(outputfile);
            fos.write(output);
            return true;
        catch(Exception e){
            return false;
}runner
public class RunRun {
    public RunRun() {
    public static void main(String args[]){
        char password[] = {'q','w','e','r','t','y'};       
        boolean enc = PWBEncryption.doIt(password,"C:\\original.txt","c:\\encrypt.txt");
        System.out.println("Encryption status == "+enc);
        boolean dec = PWBDecryption.doIt(password,"c:\\encrypt.txt","c:\\decrypt.txt");
        System.out.println("Decryption status == "+dec);
}