import java.io.*;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.*;
import java.security.cert.*;
import java.security.interfaces.*;
import javax.crypto.*;
import javax.crypto.spec.*;


//  Based on sample at:
//  http://java.sun.com/j2se/1.4.2/docs/guide/security/jce/JCERefGuide.html
//  Requires J2SE 1.5  due to bugs in earlier versions in algorithm parameters

//  Reads an encoded pkcs#8 PrivateKeyInfo file, encrypts it using PBE, wraps in
//  an EncryptedPrivateKeyInfo, writes to file;  decrypts the EncryptedPrivateKeyInfo
//  blob and displays private key parameters of original RSA private key. 

//  See also:
//  http://java.sun.com/j2se/1.5.0/docs/api/javax/crypto/EncryptedPrivateKeyInfo.html
//  http://java.sun.com/j2se/1.5.0/docs/api/java/security/spec/PKCS8EncodedKeySpec.html
//  http://www.openssl.org/docs/apps/pkcs8.html
//
//     Copyright   M. Gallant   04/07/2005

class EncPrivKeyInfo {

  public static void main(String[] args) {
   if (args.length != 1)
	System.out.println("Usage: EncPrivKeyInfo <PKCS#8PrivateKeyInfo>");
   else 
   try
	{	 
	PBEKeySpec pbeKeySpec;
	PBEParameterSpec pbeParamSpec;
	SecretKeyFactory keyFac;

	byte[] encodedprivkey =   getFileBytes(args[0]) ;
    byte[] salt = {
        (byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
        (byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
    };

	String MYPBEALG = "PBEWithSHA1AndDESede" ;
	//String MYPBEALG = "PBEWithMD5AndDES" ;
    // Iteration count
    int count = 20;

    // Create PBE parameter set
    pbeParamSpec = new PBEParameterSpec(salt, count);

    // Prompt user for encryption password.
    // Collect user password as char array (using the
    // "readPasswd" method from above), and convert
    // it into a SecretKey object, using a PBE key
    // factory.

   // System.out.print("Enter encryption password:  ");
   // System.out.flush();

    String password = "This is a stupid password!" ;
    pbeKeySpec = new PBEKeySpec(password.toCharArray());
    keyFac = SecretKeyFactory.getInstance(MYPBEALG);
    SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);

    Cipher pbeCipher = Cipher.getInstance(MYPBEALG);

    // Initialize PBE Cipher with key and parameters
    pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);


    // Encrypt the encoded Private Key with the PBE key
    byte[] ciphertext = pbeCipher.doFinal(encodedprivkey);
    // displayData(ciphertext);
	
  //----- Now construct  PKCS #8 EncryptedPrivateKeyInfo object  -----------
	AlgorithmParameters algparms = AlgorithmParameters.getInstance(MYPBEALG);
	algparms.init(pbeParamSpec) ;
	EncryptedPrivateKeyInfo encinfo = new EncryptedPrivateKeyInfo(algparms, ciphertext) ;
	
	FileOutputStream sigfos = new FileOutputStream("encrypedprivkey8");   //write PKCS#8 EncryptedPrivateKeyInfo to file
	sigfos.write(encinfo.getEncoded());
	sigfos.close();



	// ------- now recover the private key and display information --------------
	 PKCS8EncodedKeySpec pvkKeySpec = encinfo.getKeySpec(pbeKey) ;
	System.out.println("\nGot the PKCS8EncodedKeySpec .. \n") ;
	 KeyFactory keyFactory = KeyFactory.getInstance("RSA");
	 RSAPrivateKey mypvkKey = (RSAPrivateKey)keyFactory.generatePrivate(pvkKeySpec);
	 System.out.println(mypvkKey.toString()) ;



    }
   catch(Exception ioe)
	{
	 System.out.println(ioe.toString());
	}
 }


  private static void displayData(byte[] data)
  {
	int bytecon = 0;    //to get unsigned byte representation
	for(int i=1; i<=data.length ; i++){
		bytecon = data[i-1] & 0xFF ;   // byte-wise AND converts signed byte to unsigned.
           if(bytecon<16)
            System.out.print("0" + Integer.toHexString(bytecon).toUpperCase() + " ");   // pad on left if single hex digit.
            else
            System.out.print(Integer.toHexString(bytecon).toUpperCase() + " ");   // pad on left if single hex digit.
		if(i%16==0)
		  System.out.println();
	  }
  }



 private static byte[] getFileBytes(String infile){
  File f = new File(infile) ;
  int sizecontent = ((int) f.length());
  byte[] data = new byte[sizecontent];
  try 
	{
	FileInputStream freader = new FileInputStream(f);
	freader.read(data, 0, sizecontent) ;
	freader.close();
	return data;
	}
  catch(IOException ioe)
	 {
	System.out.println(ioe.toString());
	return null;
	}
}


}