How to make one file?

Question

I have basically 2 problems here
a)When I do generate a signature using the enduser's privatekey,,I will be ending up with two files one signature file and other the original document,,I need one file which contains the signature as well as the original doc in readable format and also i can authenticate doc using the same signature presemt in that file.
b)In PKI scenario shud i encrypt the doc(data) without signature or shud i encrypt the doc as well as the signature also?
c)If i have the signature as separate entity how can i find out publickey attributes or any information of the public key using the signature that is there?
Plz do repond asap with exaples if possible,
thnx in advnce
Subhash

Answer 1

Yup...I need one more help i.e I was able to encrypt/decrypt using assymtric and symetric,,the flow was like this...I had a key pair...
I generate a DES key then I create a cipher by the data string,,then i used to encrypt the des key and store it in the database...then again at the server i used to decrypt the symmetric key using the private key from the key pair and then descrypt the data...it was all well and fine..
now instaed of string i tried MSword of MSEXCELL i wasnt able to do at ll..some suggested to do padding so i tried des/cbc/pkcs5padding...it was encryting well but again i was stuck while decrypting,,it was asking for IV parametr and all,,i tried a lot but wasnt out of it...
now my question is shud i include the getIv byte even in the encrypted file also...???
i wud like to paste the code,,plz help me...
encryption part is
import java.io.*;
import java.security.*;
import java.security.spec.*;
import java.security.spec.X509EncodedKeySpec;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAKey;
import java.io.*;
import java.util.*;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.sql.*;
import java.math.BigInteger;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.Key;
import java.security.KeyFactory;
import java.security.Security;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class FileEncrypt
byte[] encryptedDESKey;
// encryptPart variables
KeyGenerator kg;
Key key;
Cipher cipher;
RSAPublicKey rsaPublicKey;
Cipher encryptCipher;
// decryptedPart variables
RSAPrivateKey priv;
Cipher decryptCipher;
byte[] decryptedDESKey;
SecretKeyFactory skf;
DESKeySpec desKeySpec;
SecretKey sk;
Cipher desCipher;
public static void main(String args[]){
     String path = "C://USB//test.doc";
     String fileName = "C://USB//ENCtest.doc";
FileEncrypt pk1 = new FileEncrypt();
String encryptedPassword = pk1.encryptPart(path,fileName);
     Connection con = null;
Statement stmt = null;
ResultSet rs = null;
//XlEncrypt tt = new XlEncrypt();
TxtFile profile = new TxtFile();
try{
DriverManager.registerDriver (profile.getDriver());
con =DriverManager.getConnection (profile.getURLName(), profile.getUserName(), profile.getPassword());
stmt = con.createStatement();
con =DriverManager.getConnection (profile.getURLName(), profile.getUserName(), profile.getPassword());
stmt = con.createStatement();
stmt.executeUpdate("insert into test (pki) values('"+encryptedPassword+"')");
}catch (SQLException e) {
System.out.println (e.getMessage() + "Problem in getting connections");
private String encryptPart(String path,String fileName){   
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
try{
// create des key
kg = KeyGenerator.getInstance("DES");
key = kg.generateKey();
// encrypt some data
//cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE,key);
//read in cert from file and get public key and decrypt des key
rsaPublicKey = getRSAPublicKey("buyer");
encryptCipher= Cipher.getInstance("RSA","BC");
encryptCipher.init(Cipher.ENCRYPT_MODE,rsaPublicKey);
encryptedDESKey = encryptCipher.doFinal(key.getEncoded());
     FileEncrypt tt = new FileEncrypt();
String sd = tt.hexEncode(encryptedDESKey);
int c;
FileInputStream fis = new FileInputStream(path);
StringBuffer fileBuffer = new StringBuffer();
while((c=fis.read())!=-1){
fileBuffer.append((char)c);
String fileString = fileBuffer.toString();
byte[] encword = cipher.doFinal(fileString.getBytes());
String outFile = tt.hexEncode(encword);
DataOutputStream out2 = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(fileName)));
out2.writeBytes(outFile);
out2.close();
return sd;
}catch(Exception e)
System.out.println("<ERROR>\nIn encryptPart\n"+e.toString()+"\n</ERROR>");
return null;
/** This array is used to convert from bytes to hexadecimal numbers */
static final char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
* A convenience method to convert an array of bytes to a String. We do
* this simply by converting each byte to two hexadecimal digits. Something
* like Base 64 encoding is more compact, but harder to encode.
public static String hexEncode(byte[] bytes) {
StringBuffer s = new StringBuffer(bytes.length * 2);
for(int i = 0; i < bytes.length; i++) {
byte b = bytes;
s.append(digits[(b & 0xf0) >> 4]);
s.append(digits[b & 0x0f]);
return s.toString();
* A convenience method to convert in the other direction, from a string
* of hexadecimal digits to an array of bytes.
public static byte[] hexDecode(String s) throws IllegalArgumentException {
try {
int len = s.length();
byte[] r = new byte[len/2];
for(int i = 0; i < r.length; i++) {
int digit1 = s.charAt(i*2), digit2 = s.charAt(i*2 + 1);
if ((digit1 >= '0') && (digit1 <= '9')) digit1 -= '0';
else if ((digit1 >= 'a') && (digit1 <= 'f')) digit1 -= 'a' - 10;
if ((digit2 >= '0') && (digit2 <= '9')) digit2 -= '0';
else if ((digit2 >= 'a') && (digit2 <= 'f')) digit2 -= 'a' - 10;
r[i] = (byte)((digit1 << 4) + digit2);
return r;
catch (Exception e) {
throw new IllegalArgumentException("hexDecode(): invalid input");
// encryptPart private method
private RSAPublicKey getRSAPublicKey(String userName){
try{
FileInputStream fis = new FileInputStream("C:/certificates/buyer/buyer.crt");
BufferedInputStream bis = new BufferedInputStream(fis);
CertificateFactory cf = CertificateFactory.getInstance("X.509");
X509Certificate cert = null;
while(bis.available() > 0){
cert = (X509Certificate)cf.generateCertificate(bis);
return (RSAPublicKey)cert.getPublicKey();
catch(Exception e){
System.out.println("<ERROR>\nTrying to get Public Key from cert\n"+e.toString()+"\n</ERROR>");
return null;
decryption part is
import java.io.*;
import java.security.*;
import java.security.spec.*;
import java.security.spec.X509EncodedKeySpec;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAKey;
import java.io.*;
import java.util.*;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.sql.*;
import java.math.BigInteger;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.Key;
import java.security.KeyFactory;
import java.security.Security;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.*;
import java.security.spec.*;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class FileDecrypt
byte[] encryptedDESKey;
// encryptPart variables
KeyGenerator kg;
Key key;
Cipher cipher;
RSAPublicKey rsaPublicKey;
Cipher encryptCipher;
// decryptedPart variables
RSAPrivateKey priv;
Cipher decryptCipher;
byte[] decryptedDESKey;
SecretKeyFactory skf;
DESKeySpec desKeySpec;
SecretKey sk;
Cipher desCipher;
public static void main(String args[]){
     String inputFile = "C://Usb//ENCtest.doc";
     Connection con = null;
Statement stmt = null;
ResultSet rs = null;
     TxtFile profile = new TxtFile();
     String var="";
     try {
DriverManager.registerDriver (profile.getDriver());
con =DriverManager.getConnection (profile.getURLName(), profile.getUserName(), profile.getPassword());
stmt = con.createStatement();
con =DriverManager.getConnection (profile.getURLName(), profile.getUserName(), profile.getPassword());
stmt = con.createStatement();
rs = stmt.executeQuery("select pki from test");
if(rs.next()){
var = rs.getString("pki");
}catch (SQLException e) {
System.out.println (e.getMessage() + "Problem in getting connections");
     System.out.println(var);
     String encSymKey = var;
     FileDecrypt tpk = new FileDecrypt();
String decryptedPassword = tpk.decryptPart(inputFile,encSymKey);
//return decryptedPassword;     
private String decryptPart(String inputFile,String encSymKey)
try{   
// get private key from file
priv = getRSAPrivateKey();
// decrypted des key
int c;
Security.addProvider(new BouncyCastleProvider());
FileDecrypt t1 = new FileDecrypt();
byte[] encryptedDESKey1 = t1.hexDecode(encSymKey);
decryptCipher = Cipher.getInstance("RSA","BC");
decryptCipher.init(Cipher.DECRYPT_MODE,priv);
decryptedDESKey = decryptCipher.doFinal(encryptedDESKey1);
// convert bytes back to des key
skf = SecretKeyFactory.getInstance("DES");
desKeySpec = new DESKeySpec(decryptedDESKey);
sk = skf.generateSecret(desKeySpec);
// decrypt the encrypted password
//desCipher = desCipher.getInstance("DES/ECB/PKCS5Padding");
desCipher = desCipher.getInstance("DES");
               desCipher.init(Cipher.DECRYPT_MODE,sk);     
//desCipher.init(Cipher.DECRYPT_MODE,sk);
FileDecrypt obj1 = new FileDecrypt();
FileInputStream fis = new FileInputStream(inputFile);
StringBuffer encryptedFile = new StringBuffer();
while((c=fis.read())!=-1){
encryptedFile.append((char)c);
String encFile = encryptedFile.toString();
System.out.println(encFile);
byte[] jk =obj1.hexDecode(encFile);
String encVar = new String(desCipher.doFinal(jk));
//String encVar = new String(desCipher.doFinal(jk));
DataOutputStream out2 = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("C:/usb/dectest.doc")));
out2.writeBytes(encVar);
out2.close();
//System.out.println(new String(desCipher.doFinal(jk)));
return new String("subhash");
}catch(Exception e){
System.out.println("<ERROR>\nIn decryptPart\n"+e.toString()+"\n</ERROR>");
return null;
// decryptPart private method
private RSAPrivateKey getRSAPrivateKey()
try{
File keyFile = new File("C:/certificates/buyer/buyerkey.der");
DataInputStream in = new DataInputStream(new FileInputStream(keyFile));
byte [] fileBytes = new byte[(int) keyFile.length()];
in.readFully(fileBytes);
in.close();
KeyFactory kf = KeyFactory.getInstance("RSA");
KeySpec ks = new PKCS8EncodedKeySpec(fileBytes);
return (RSAPrivateKey)kf.generatePrivate(ks);
}catch(Exception e){
System.out.println("<ERROR>\nTrying to get Private Key from file\n"+e.toString()+"\n</ERROR>");
return null;
/** This array is used to convert from bytes to hexadecimal numbers */
static final char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
* A convenience method to convert an array of bytes to a String. We do
* this simply by converting each byte to two hexadecimal digits. Something
* like Base 64 encoding is more compact, but harder to encode.
public static String hexEncode(byte[] bytes) {
StringBuffer s = new StringBuffer(bytes.length * 2);
for(int i = 0; i < bytes.length; i++) {
byte b = bytes[i];
s.append(digits[(b & 0xf0) >> 4]);
s.append(digits[b & 0x0f]);
return s.toString();
* A convenience method to convert in the other direction, from a string
* of hexadecimal digits to an array of bytes.
public static byte[] hexDecode(String s) throws IllegalArgumentException {
try {
int len = s.length();
byte[] r = new byte[len/2];
for(int i = 0; i < r.length; i++) {
int digit1 = s.charAt(i*2), digit2 = s.charAt(i*2 + 1);
if ((digit1 >= '0') && (digit1 <= '9')) digit1 -= '0';
else if ((digit1 >= 'a') && (digit1 <= 'f')) digit1 -= 'a' - 10;
if ((digit2 >= '0') && (digit2 <= '9')) digit2 -= '0';
else if ((digit2 >= 'a') && (digit2 <= 'f')) digit2 -= 'a' - 10;
r[i] = (byte)((digit1 << 4) + digit2);
return r;
}catch (Exception e) {
throw new IllegalArgumentException("hexDecode(): invalid input");
plz do reply asap,,
bye
Subhash