public FileData decryptFile(FileData fd) throws IOException {
ByteArrayInputStream input = fd.getInputStream();
ByteArrayOutputStream output = new ByteArrayOutputStream();
BASE64Decoder base64 = new BASE64Decoder();
byte[] bytearr = base64.decodeBuffer(input);
input = new ByteArrayInputStream(bytearr);
Cipher cipher = null;
try {
cipher = Cipher.getInstance("Blowfish/ECB/PKCS5Padding");
} catch (Exception e) {
throw new IOException(e);
}
try {
cipher.init(Cipher.DECRYPT_MODE, key);
} catch (Exception e) {
throw new IOException(e);
}
int length = -1;
CipherInputStream stream = new CipherInputStream(input, cipher);
while ((length = stream.read(bytearr)) != -1) {
output.write(bytearr, 0, length);
}
output.close();
String path = fd.getPath().replaceAll("\\.(.*)_enc", "\\.$1");
return new FileData(path, output.toByteArray());
}
/** This encryption/decryption code doesn't match outputs with the Python code. It needs fixed. */
public byte[] decrypt(byte[] encryptedBytes) { // , byte[] iv
String output = null;
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
try {
SecretKeySpec key = generatekey();
// Cipher decryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
// IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
// decryptCipher.init(Cipher.DECRYPT_MODE, key, ivParameterSpec);
Cipher decryptCipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
decryptCipher.init(Cipher.DECRYPT_MODE, key);
outputStream = new ByteArrayOutputStream();
ByteArrayInputStream inStream = new ByteArrayInputStream(encryptedBytes);
CipherInputStream cipherInputStream = new CipherInputStream(inStream, decryptCipher);
byte[] buf = new byte[1024];
int bytesRead;
while ((bytesRead = cipherInputStream.read(buf)) >= 0) {
outputStream.write(buf, 0, bytesRead);
}
output = new String(outputStream.toByteArray(), "UTF-8");
Log.d(TAG, output);
cipherInputStream.close();
inStream.close();
} catch (InvalidKeyException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
// Log.e(TAG,e.getCause().toString());
Log.e(TAG, e.getMessage());
return null;
} /*catch (InvalidAlgorithmParameterException e) {
e.printStackTrace();
return null;
}*/ catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
return null;
}
// return output;
return outputStream.toByteArray();
}
String getDecryptedData(RSAPrivateKey key)
throws InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException,
NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, IOException {
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidOpenSSL");
cipher.init(Cipher.DECRYPT_MODE, key);
CipherInputStream cipherInputStream =
new CipherInputStream(new FileInputStream(getFilePath()), cipher);
byte[] roundTrippedBytes = new byte[1000]; // TODO: dynamically resize
// as we get more data
int index = 0;
int nextByte;
while ((nextByte = cipherInputStream.read()) != -1) {
roundTrippedBytes[index] = (byte) nextByte;
index++;
}
cipherInputStream.close();
return new String(roundTrippedBytes, 0, index, "UTF-8");
}
private void runTest(String name) throws Exception {
String lCode = "ABCDEFGHIJKLMNOPQRSTUVWXY0123456789";
KeyGenerator kGen;
if (name.indexOf('/') < 0) {
kGen = KeyGenerator.getInstance(name, "BC");
} else {
kGen = KeyGenerator.getInstance(name.substring(0, name.indexOf('/')), "BC");
}
Cipher in = Cipher.getInstance(name, "BC");
Cipher out = Cipher.getInstance(name, "BC");
Key key = kGen.generateKey();
ByteArrayInputStream bIn = new ByteArrayInputStream(lCode.getBytes());
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
in.init(Cipher.ENCRYPT_MODE, key);
if (in.getIV() != null) {
out.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(in.getIV()));
} else {
out.init(Cipher.DECRYPT_MODE, key);
}
CipherInputStream cIn = new CipherInputStream(bIn, in);
CipherOutputStream cOut = new CipherOutputStream(bOut, out);
int c;
while ((c = cIn.read()) >= 0) {
cOut.write(c);
}
cIn.close();
cOut.flush();
cOut.close();
String res = new String(bOut.toByteArray());
if (!res.equals(lCode)) {
fail("Failed - decrypted data doesn't match.");
}
}
public static String decrypt(String cryptedText, String password) {
String dec = "";
try {
// convert to byte array
PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray());
// METHOD = "PBEWITHSHA-1AND128BITAES-CBC-BC";
// //PBEWITHSHA256AND128BITAES-CBC-BC";//PBEWithMD5AndDES";
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(METHOD);
SecretKey secretKey = keyFactory.generateSecret(keySpec);
PBEParameterSpec parameterSpec = new PBEParameterSpec(salt, iterationCount);
cipher = Cipher.getInstance(METHOD);
cipher.init(Cipher.DECRYPT_MODE, secretKey, parameterSpec);
decryptedText = new ByteArrayInputStream(cryptedText.getBytes());
CipherInputStream in = new CipherInputStream(decryptedText, cipher);
byte contents = (byte) in.read();
char c = 82;
while (contents != -1) {
fileBytes.add(new Byte(contents));
c = (char) Integer.parseInt(fileBytes.get(fileBytes.size() - 1) + "");
dec = dec + c;
contents = (byte) in.read();
}
in.close();
} catch (IOException ex) {
Logger.getLogger(Logic.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidKeyException ex) {
Logger.getLogger(Logic.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidAlgorithmParameterException ex) {
Logger.getLogger(Logic.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidKeySpecException ex) {
Logger.getLogger(Logic.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Logic.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchPaddingException ex) {
Logger.getLogger(Logic.class.getName()).log(Level.SEVERE, null, ex);
}
return dec;
}
/**
* Read crypted data from the highscore-file.
*
* @return the decrypted data in the file.
* @see ObjectInputStream#readObject
*/
@SuppressWarnings("unchecked")
private void readHighscore() {
FileInputStream fis = null;
CipherInputStream cis = null;
ObjectInputStream ois = null;
entries = new ArrayList<HighscoreEntry>();
try {
fis = new FileInputStream(GameConstants.HIGHSCORE_FILE_NAME);
cis = new CipherInputStream(fis, dcipher);
ois = new ObjectInputStream(cis);
this.entries = (ArrayList<HighscoreEntry>) ois.readObject();
ois.close();
cis.close();
fis.close();
} catch (FileNotFoundException e) {
entries = new ArrayList<HighscoreEntry>();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception {
// prompt user to enter a port number
System.out.print("Enter the port number: ");
Scanner scan = new Scanner(System.in);
int port = scan.nextInt();
scan.nextLine();
System.out.print("Enter the host name: ");
String hostName = scan.nextLine();
// Initialize a key pair generator with the SKIP parameters we sepcified, and genrating a pair
// This will take a while: 5...15 seconrds
System.out.println("Generating a Diffie-Hellman keypair: ");
KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH");
kpg.initialize(PARAMETER_SPEC);
KeyPair keyPair = kpg.genKeyPair();
System.out.println("key pair has been made...");
// one the key pair has been generated, we want to listen on
// a given port for a connection to come in
// once we get a connection, we will get two streams, One for input
// and one for output
// open a port and wait for a connection
ServerSocket ss = new ServerSocket(port);
System.out.println("Listeining on port " + port + " ...");
Socket socket = ss.accept();
// use to output and input primitive data type
DataOutputStream out = new DataOutputStream(socket.getOutputStream());
// next thing to do is send our public key and receive client's
// this corresponds to server step 3 and step 4 in the diagram
System.out.println("Sending my public key...");
byte[] keyBytes = keyPair.getPublic().getEncoded();
out.writeInt(keyBytes.length);
out.write(keyBytes);
System.out.println("Server public key bytes: " + CryptoUtils.toHex(keyBytes));
// receive the client's public key
System.out.println("Receiving client's public key...");
DataInputStream in = new DataInputStream(socket.getInputStream());
keyBytes = new byte[in.readInt()];
in.readFully(keyBytes);
// create client's public key
KeyFactory kf = KeyFactory.getInstance("DH");
X509EncodedKeySpec x509Spec = new X509EncodedKeySpec(keyBytes);
PublicKey clientPublicKey = kf.generatePublic(x509Spec);
// print out client's public key bytes
System.out.println(
"Client public key bytes: " + CryptoUtils.toHex(clientPublicKey.getEncoded()));
// we can now use the client's public key and
// our own private key to perform the key agreement
System.out.println("Performing the key agreement ... ");
KeyAgreement ka = KeyAgreement.getInstance("DH");
ka.init(keyPair.getPrivate());
ka.doPhase(clientPublicKey, true);
// in a chat application, each character is sendt over the wire, separetly encrypted,
// Instead of using ECB, we are goin to use CFB, with a block size of 8 bits(1byte)
// to send each character. We will encrypt the same character in a different way
// each time. But in order to use CFB8, we need an IVof 8 bytes. We will create
// that IV randomly and and send it to the client. It doesn't matter if somoene
// eavesdrops on the IV when it is sent over the wire. it's not sensitive info
// creating the IV and sending it corresponds to step 6 and 7
byte[] iv = new byte[8];
SecureRandom sr = new SecureRandom();
sr.nextBytes(iv);
out.write(iv);
// we generate the secret byte array we share with the client and use it
// to create the session key (Step 8)
byte[] sessionKeyBytes = ka.generateSecret();
// create the session key
SecretKeyFactory skf = SecretKeyFactory.getInstance("DESede");
DESedeKeySpec DESedeSpec = new DESedeKeySpec(sessionKeyBytes);
SecretKey sessionKey = skf.generateSecret(DESedeSpec);
// printout session key bytes
System.out.println("Session key bytes: " + CryptoUtils.toHex(sessionKey.getEncoded()));
// now use tha that session key and IV to create a CipherInputStream. We will use them to read
// all character
// that are sent to us by the client
System.out.println("Creating the cipher stream ...");
Cipher decrypter = Cipher.getInstance("DESede/CFB8/NoPadding");
IvParameterSpec spec = new IvParameterSpec(iv);
decrypter.init(Cipher.DECRYPT_MODE, sessionKey, spec);
CipherInputStream cipherIn = new CipherInputStream(socket.getInputStream(), decrypter);
// we just keep reading the input and print int to the screen, until -1 sent over
int theCharacter = 0;
theCharacter = cipherIn.read();
while (theCharacter != -1) {
System.out.print((char) theCharacter);
theCharacter = cipherIn.read();
}
// once -1 is received we want to close up our stream and exit
cipherIn.close();
in.close();
out.close();
socket.close();
}
