I am a beginner in Java Programming. My code encrypts data extracted from a text file and stores it in another file using RSA algorithm. I want to make my Private Key password protected by using the KeyStore class (http://download.oracle.com/javase/1,5.0/docs/api/java/security/KeyStore.html) and it’s nested class – KeyStore.PrivateKeyEntry (http://download.oracle.com/javase/1,5.0/docs/api/java/security/KeyStore.PrivateKeyEntry.html).
The constructor of KeyStore.PrivateKeyEntry requires a Certificate[] array and I am not sure about how to generate this Certificate[] array.
I am attaching my code so far along with the question:
This is the Encryption code.
public class Fileencrypt {
public static void main(String args[]) throws IOException, InvalidKeyException, java.security.InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, KeyStoreException, CertificateException, CertificateEncodingException, IllegalStateException, NoSuchProviderException, SignatureException, UnrecoverableKeyException{
try{
byte[] plainData;
byte[] encryptedData = null;
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(2048);
KeyPair kp = kpg.genKeyPair();
PublicKey publicKey = kp.getPublic();
PrivateKey privateKey = kp.getPrivate();
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
try {
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(publicKey.getEncoded());
FileOutputStream fos = new FileOutputStream("C:\\Output\\Publickey.txt");
fos.write(x509EncodedKeySpec.getEncoded());
fos.close();
// Store Private Key.
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(privateKey.getEncoded());
fos = new FileOutputStream("C:\\Output\\Privatekey.txt");
fos.write(pkcs8EncodedKeySpec.getEncoded());
fos.close();
} catch (IOException e) {
System.out.println(e.getMessage());
}
File f = new File("C:\\Output\\text.txt");
FileInputStream in = new FileInputStream(f);
plainData = new byte[(int)f.length()];
in.read(plainData);
try {
encryptedData = cipher.doFinal(plainData);
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
System.out.println(encryptedData);
FileOutputStream target = new FileOutputStream(new File("C:\\Output\\encrypted.txt"));
target.write(encryptedData);
target.close();
}
catch(IOException e){e.printStackTrace();}
catch(InvalidKeyException ei){ei.printStackTrace();
}
}
}
This is the Decryption code.
public class Filedecrypt {
public static void main(String args[]) throws IOException,
InvalidKeyException, java.security.InvalidKeyException,
NoSuchAlgorithmException, NoSuchPaddingException,
BadPaddingException {
try {
byte[] plainData = null;
byte[] encryptedData;
File f1 = new File("C:\\Output\\Privatekey.txt");
FileInputStream in1 = new FileInputStream(f1);
byte[] bytekey = new byte[(int) f1.length()];
in1.read(bytekey);
KeyFactory keyFac = KeyFactory.getInstance("RSA");
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(bytekey);
PrivateKey key = keyFac.generatePrivate(keySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, key);
File f = new File("C:\\Output\\encrypted.txt");
FileInputStream in = new FileInputStream(f);
encryptedData = new byte[(int) f.length()];
in.read(encryptedData);
try {
plainData = cipher.doFinal(encryptedData);
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
FileOutputStream target = new FileOutputStream(
new File(
"C:\\Output\\text1.txt"));
target.write(plainData);
target.close();
} catch (IOException e) {
e.printStackTrace();
} catch (InvalidKeyException ei) {
ei.printStackTrace();
} catch (InvalidKeySpecException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
If you want to save private key with certificate you can use something like this:
or another similar method I have: