Using string password

Question

Hi
Can someone give me a sample code about how to use string password when encrypting and decrypting data?
I have made an application that encrypts and decrypts data and it can even save password. Password is not created from string see code:
KeyGenerator kgen = KeyGenerator.getInstance("Blowfish");
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(raw, "Blowfish");
Now I want that client can give a password and application use that while encrypting and decrypting.
I'm using CipherOutputStream and CipherInputStream to save and open data. I'm using Blowfish algorithm.
Regards
Juha

Answer 1

Hi Juha,
Here is the sample code for encrypting and decrypting a string.
import java.io.*;
import java.security.*;
import javax.crypto.*;
import sun.misc.*;
public class SecretWriting{
public static void main(String args[]) throws Exception{
if(args.length<2)
System.out.println("Usage : SecretWriting -e|-d text");
return;
Security.addProvider(new com.sun.crypto.provider.SunJCE());
Key key;
try{
ObjectInputStream in=new ObjectInputStream(new FileInputStream("des.key"));
key=(Key)in.readObject();
in.close();
catch(FileNotFoundException fnfe)
KeyGenerator generator= KeyGenerator.getInstance("DES");
generator.init(new SecureRandom() );
key=generator.generateKey();
ObjectOutputStream out=new ObjectOutputStream(new FileOutputStream("des.key"));
out.writeObject(key);
out.close();
Cipher cipher=Cipher.getInstance("DES/ECB/PKCS5Padding");
if(args[0].indexOf("e") !=-1)
cipher.init(Cipher.ENCRYPT_MODE,key);
String amalgam=args[1];
for(int i=2;i<args.length;i++)
amalgam+=" "+args;
byte[] stringBytes=amalgam.getBytes("UTF8");
byte[] raw=cipher.doFinal(stringBytes);
BASE64Encoder encoder = new BASE64Encoder();
String base64 = encoder.encode(raw);
System.out.println(base64);
else if(args[0].indexOf("d")!=-1)
cipher.init(Cipher.DECRYPT_MODE,key);
BASE64Decoder decoder = new BASE64Decoder();
byte[] raw = decoder.decodeBuffer(args[1]);
byte[] stringBytes = cipher.doFinal(raw);
String result = new String(stringBytes,"UTF8");
System.out.println(result);
I hope this will help you out.
Thanks
Bakrudeen
Technical Support Engineer
Sun MicroSystems Inc, India