/*
* Concept profile generation tool suite
* Copyright (C) 2015 Biosemantics Group, Erasmus University Medical Center,
* Rotterdam, The Netherlands
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
*/
package org.erasmusmc.utilities;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStreamWriter;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
public class WriteEncryptedFile {
public static KeyPair generateKeyPair(){
KeyPair result = null;
KeyPairGenerator keygen;
try {
keygen = KeyPairGenerator.getInstance("RSA");
keygen.initialize(512);
result = keygen.generateKeyPair();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return result;
}
public static void saveKey(Key key, String filename){
saveRawKey(filename, key);
}
public static Key loadKey(String filename){
return loadRawKey(filename);
}
private static Key loadRawKey(String filename) {
Key result = null;
try {
FileInputStream binFile = new FileInputStream(filename);
try {
ObjectInputStream inp = new ObjectInputStream(binFile);
try {
result = (Key)inp.readObject();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return result;
}
private static void saveRawKey(String filename, Key key) {
try {
FileOutputStream binFile = new FileOutputStream(filename);
try {
ObjectOutputStream out = new ObjectOutputStream(binFile);
out.writeObject(key);
} catch (IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
public WriteEncryptedFile(String filename, String keyFilename){
this(filename, loadKey(keyFilename));
}
public WriteEncryptedFile(String filename, Key publicKey){
try{
//Step 1: generate random symmetric key (AES algorithm):
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128);
SecretKey aesKey = kgen.generateKey();
//Step 2: Create encoding cipher using public key (RSA algorithm):
Cipher rsaCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
rsaCipher.init(Cipher.ENCRYPT_MODE, publicKey);
//Step 3: Open file stream:
FileOutputStream file = new FileOutputStream(filename);
//Step 4: Encode symmetric key using encoding cipher, and write to file:
file.write(rsaCipher.doFinal(aesKey.getEncoded()));
//Step 5: Open encrypted stream using symmetric key (AES algorithm):
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, aesKey);
CipherOutputStream out = new CipherOutputStream(file, cipher);
bufferedWrite = new BufferedWriter(new OutputStreamWriter(out));
} catch (Exception e){
e.printStackTrace();
}
}
public void writeln(String string){
try {
bufferedWrite.write(string);
bufferedWrite.newLine();
} catch (IOException e) {
e.printStackTrace();
}
}
public void flush(){
try {
bufferedWrite.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
public void close() {
try {
bufferedWrite.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private BufferedWriter bufferedWrite;
}