/*
 * KeyHandler.java (för 10.1)
 * Karl-Adam Karlsson
 * 06-10-05
 *
 *
 */
import javax.crypto.*;
import java.security.*;
import java.io.*;


public class KeyHandler{

	public KeyHandler(String privateName, String publicName){
		KeyPair aPair = genKeys(1024);
		saveKey(privateName, aPair.getPrivate());
		saveKey(publicName, aPair.getPublic());
	}//end of constructor

	
	/*
	* genKeys generates and returns a keypair of desired Size.
 	* 
	*
	* @param int keysize the desired size of the keypair
	*
	* @returns KeyPair of size keysize
	*
	*/
	private KeyPair genKeys(int keysize){
		KeyPairGenerator aGenerator = null;
		String alg1 = "DSA";
		
		try{
			aGenerator = KeyPairGenerator.getInstance(alg1);
			aGenerator.initialize(keysize);
			
		}catch(NoSuchAlgorithmException alEx){
			System.err.print(alEx);
			System.exit(1);
		}

	return aGenerator.generateKeyPair();	
	}//end of genKeys

	/*
	* SaveKey saves a Key to file.
	* Both key to be saved and filename are parameters.
 	*
	* @param String fileName The file to save to.
	* @param Key aKey The key to be saved.
	*
	*/
	private void saveKey(String fileName, Key aKey){	
		File outFile  = new File(fileName);                    
		FileOutputStream outStream;            
		ObjectOutputStream oStream;
	

		try{
   			outStream = new FileOutputStream(outFile);
   			oStream = new ObjectOutputStream(outStream);
			oStream.writeObject(aKey);
			oStream.close();
			outStream.close();
   		
		} catch(IOException e) {
   			System.err.println("IO Exception");
   			e.printStackTrace();
   			System.exit(1);
		}
		
		
	}//endof saveKey



	/*
	* main
	* 
	*/
	public static void main (String[] args) {
		if(args==null || args.length < 2 ||args.length>2){
			System.out.print("Usage:\njava KeyHandler <privateKey> <publicKey>\n");
			System.out.println("Where <privateKey> is desired name of private keyfile.");
			System.out.println("Where <publicKey> is desired name of public keyfile.");
		}
		else if(args.length==2&&args[0]!=null&&args[1]!=null){
			new KeyHandler(args[0],args[1]);
		}
		else if(args[0]==null||args[1]==null){
			System.out.print("Usage:\njava KeyHandler <privateKey> <publicKey>\n");
			System.out.println("Where <privateKey> is desired name of private keyfile.");
			System.out.println("Where <publicKey> is desired name of public keyfile.");
		}
  		
  	}//end of main
}//end of Class