File Encryption: New to Java encryption plz help

Question

ive been looking at some code i got from a friends java book about how to encode/decode stuff. It seems to me that the key that is generated would be a one time thing and you would get a new one the next time you tried. If that happened i would think at least you would not decode the text correctly that had previosly been encoded by a different key. Plz point out another example for what im trying to do if this one is doing something else which it seems to me it must be. Or if not plz explain how it works. Thanks for youre time.
heres the code ive been looking at to learn how to encode/decode files for a game ive been working on:
import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.awt.*;
import java.util.*;
public class TestCipher{
     public static void main(String args[]) throws Exception {
               Set set = new HashSet();
               System.out.println("Enter password\nMust contain at least 8 characters");
               BufferedReader first = new BufferedReader(new
               InputStreamReader(System.in));
               //password must be at leaste 8 charaacters
               //private static final
               String password = "uuuuuuuu";
               password = first.readLine();
               Random random = new Random();
               for (int i=0; i<10; i++){
                    Point point = new Point(random.nextInt(1000), random.nextInt(2000));
                    set.add(point);
               int last = random.nextInt(5000);
               //create key
               byte key[] = password.getBytes();
               DESKeySpec desKeySpec = new DESKeySpec(key);
               SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
               SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
               //create Cipher
               Cipher desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
               desCipher.init(Cipher.ENCRYPT_MODE, secretKey);
               //create Stream
               FileOutputStream fos = new FileOutputStream("out.des");
               BufferedOutputStream bos = new BufferedOutputStream(fos);
               CipherOutputStream cos = new CipherOutputStream(bos, desCipher);
               ObjectOutputStream oos = new ObjectOutputStream(cos);
               //write objects
               oos.writeObject(set);
               oos.writeInt(last);
               oos.flush();
               oos.close();
               //change Cipher Mode
               desCipher.init(Cipher.DECRYPT_MODE, secretKey);
               //Create Stream
               FileInputStream fis = new FileInputStream("out.des");
               BufferedInputStream bis = new BufferedInputStream(fis);
               CipherInputStream cis = new CipherInputStream(bis, desCipher);
               ObjectInputStream ois = new ObjectInputStream(cis);
               //read objects
               Set set2 = (Set)ois.readObject();
               int last2 = ois.readInt();
               ois.close();
               //compare original with what is read back
               int count = 0;
               if (set.equals(set2)){
                    System.out.println("Set1:" + set);
                    System.out.println("Set2:" + set2);
                    System.out.println("Sets are okay.");
                    count++;
               if (last == last2){
                    System.out.println("int1:" + last);
                    System.out.println("int2:" + last2);
                    System.out.println("ints are okay.");
                    count++;
               if (count != 2){
                    System.out.println("Problem during encryption/decryption");

Answer 1

You can use EnvelopedDataGenerator from BC library.
FileInputStream src = new FileInputStream(inputFile); // File to encrypt
byte[] data = new byte[src.available()];
src.read(data);
src.close();               
CMSEnvelopedDataGenerator dataGenerator =new CMSEnvelopedDataGenerator();     
dataGenerator.addKeyTransRecipient(getPersonalCertificate()); // add personal certificate
// OPTIONAL add other recipients certificates who can decode
dataGenerator.addKeyTransRecipient(cert1);
CMSProcessableByteArray byteArray =new CMSProcessableByteArray(data);     
CMSEnvelopedData envelopedData = dataGenerator.generate(byteArray, CMSEnvelopedDataGenerator.DES_EDE3_CBC, "BC");
FileOutputStream fos = new FileOutputStream(outputFile);
fos.write(envelopedData.getEncoded());
fos.close();