/*
 * SignHandler.java (för 10.2)
 * Karl-Adam Karlsson
 * 06-10-09
 *
 * java SignHandler <keystore> <keystore_password> <alias> <key_password> <data> <certificate> <signature>
 * signerar filen <data> med (den privata) nyckeln som finns i <keystore> under namnet <alias>, sparar ett certifikat
 * som  (innehållande den publika nyckeln) i filen <certificate> och sparar signaturen i filen <signature>
 * (sändaren kan sedan skicka filerna <data>, <signature> och <certificate> till mottagaren för verifiering)
 *
 */
import java.security.*;
import java.io.*;

public class SignHandler{

	/*
	 * Konstruktor
	 */
	public SignHandler(String kStore,String storePass, String alias, String keyPass, String dataPath, String certName, String sigName){
		KeyStore store = loadKeyStore(kStore, storePass);
		
		try{
			signAndSaveSig(getInS(dataPath), store.getKey(alias,keyPass.toCharArray()), sigName);
			saveCert(store.getCertificate(alias), certName);
		}catch(KeyStoreException kex){
			kex.printStackTrace();
			System.exit(1);	
		}catch(NoSuchAlgorithmException noA){
			noA.printStackTrace();
			System.exit(1);	
		}catch(UnrecoverableKeyException kk){
			kk.printStackTrace();
			System.exit(1);	
		}
	}
	
	/*
	 * Saves the public key to a file called <certName>
	 * @param Certificate acert The certificate to be saved.
	 * @param String cerName The name of the file to save the key to.
	 *
	 */
	private void saveCert(java.security.cert.Certificate aCert, String certName){
		File f = new File(certName);
		FileOutputStream outFile  = null;      
		ObjectOutputStream outStream;            
		
		try{
			outFile = new FileOutputStream(certName);    
   			outStream = new ObjectOutputStream(outFile);
        	outStream.writeObject(aCert);
       		outStream.close();
   		
		} catch(IOException e) {
   			System.err.println("IO Exception");
   			e.printStackTrace();
   			System.exit(1);
		} 
	}//end of saveCert
	
	/*
	 * Signs the file referenced by instream with the privat key aKey
	 * And saves the signature to a file named sigName
	 * 
	 * @param inStream A instream to the file to sign
	 * @param Key aKey The key to use for signing
	 * @param sigName The Name of the signature file to save signature to.
	 */
	private void signAndSaveSig(FileInputStream inStream, Key aKey, String sigName){
		File aFile  = new File(sigName);
		Signature aSig = null;
		byte[] signature = null;
		
		try{
			aSig = Signature.getInstance( "SHA1withDSA" );
			aSig.initSign( (PrivateKey)aKey );
		}catch(NoSuchAlgorithmException noAl){
			System.err.println(noAl);
			System.exit(1);	
		}catch(InvalidKeyException inKey){
			System.err.println(inKey);
			System.exit(1);	
		}
		

		int aLen;
		byte[] buffLn = new byte[1024];
		
		try{
	        	while ((aLen = inStream.read(buffLn)) != -1) {
    	    	             aSig.update( buffLn );
        		}
        		
        		signature = aSig.sign();
        		saveSig(sigName, signature);        
				inStream.close();
				
        }catch(IOException ioe){
        	ioe.printStackTrace();
			System.exit(1);	
        }catch(SignatureException sigEx){
        	sigEx.printStackTrace();
			System.exit(1);	
        }
	}//end of file
	
	/*
	* SaveSig saves a Signature to file.
	* Both Signature to be saved and filename are parameters.
 	*
	* @param String fileName The file to save to.
	* @param byte[] aSig The Signature, in bytes, to be saved.
	*
	*/
	private void saveSig(String fileName, byte[] aSig){	
		File outFile  = new File(fileName);          
		FileOutputStream outStream;            
		
		try{
   			outStream = new FileOutputStream(fileName);
        	outStream.write(aSig);
       		outStream.close();
   		
		} catch(IOException e) {
   			System.err.println("IO Exception");
   			e.printStackTrace();
   			System.exit(1);
		}
			
	}//endof saveSig
	
	/*
	* getInS
	* Returns a FileInputStream connected to a file
	* @param String fimeName The name of the file to connect the stream to.
	* @return FileInputStream A stream connected to the file.
	*/
	private FileInputStream getInS(String fileName){
		FileInputStream inFstream = null;
		
		try{
			inFstream = new FileInputStream(fileName);
		}catch(FileNotFoundException fEx){
			fEx.printStackTrace();;
			System.exit(1);
		}
	return inFstream;	
	}//end of getInS
	
	/*
	* loadKeyStore
	* Loads a KeyStore Object from the file named <keyFileName>
	* @param keyFileName Name of file to load keypair from
	* @return KeyStore the loaded keystore.
	*/
	private KeyStore loadKeyStore(String keyFileName, String keyPass){
			KeyStore aStore = null;
			System.out.println("Pass: "+keyPass);
			System.out.println("aschararray: "+keyPass.toCharArray());
			
			try{
				aStore = KeyStore.getInstance(KeyStore.getDefaultType());
				aStore.load(new FileInputStream(keyFileName), keyPass.toCharArray());
			}catch(IOException ioe){
				ioe.printStackTrace();
				System.exit(1);	
			}catch(NoSuchAlgorithmException alE){
				alE.printStackTrace();
				System.exit(1);	
			}catch(java.security.cert.CertificateException cex){
				cex.printStackTrace();
				System.exit(1);	
			}catch(KeyStoreException kex){
				kex.printStackTrace();
				System.exit(1);	
			}
	
	return aStore;
	}//end of loadKeyPair


	/*
	* main
	* 
	*/
	public static void main (String[] args) {
	
		if(args==null || args.length != 7){
			System.out.println("Usage:java SignHandler <keystore> <keystore_password> <alias> <key_password> <data> <certificate> <signature>");
			System.out.println("Where <keysore> is the keystore to use.");
			System.out.println("Where <alias> is the alias specified in the keystore.");
			System.out.println("Where <keysore_password> is the password for this keystore.");
			System.out.println("Where <key_password> is the password for the key.");
			System.out.println("Where <data> is the file to sign.");
			System.out.println("Where <certificate> is the filename to save certificate to.");
			System.out.println("Where <signature> is the filename to save signature to.");
	}
	else if(args.length==7&&args[0]!=null&&args[1]!=null&&args[2]!=null&&args[3]!=null&&args[4]!=null&&args[5]!=null&&args[6]!=null){
			new SignHandler(args[0],args[1],args[2],args[3],args[4],args[5],args[6]);
		}
		else if(args[0]==null||args[1]==null||args[2]==null||args[3]==null||args[4]==null||args[5]==null||args[6]==null){
			System.out.println("null is NOT a Valid argument.");
			System.out.println("Usage:java SignHandler <keystore> <keystore_password> <alias> <key_password> <data> <certificate> <signature>");
			System.out.println("Where <keysore> is the keystore to use.");
			System.out.println("Where <alias> is the alias specified in the keystore.");
			System.out.println("Where <keysore_password> is the password for this keystore.");
			System.out.println("Where <key_password> is the password for the key.");
			System.out.println("Where <data> is the file to sign.");
			System.out.println("Where <certificate> is the filename to save certificate to.");
			System.out.println("Where <signature> is the filename to save signature to.");
		}
  		
  	}//end of main
}//end of Class