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How to encrypt & decrypt large video file

I would like to store video files in storage that can be accessed only my application. outside the user should not be able to access his video. I tried Encryption & Decryption but the video file is too large (1GB) it takes a lot of time.
Do you have any Idea guys how can I do?
Please find below my Encryption & Decryption Code :
private File sdCardRoot;
private ProgressBar progressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sdCardRoot = Environment.getExternalStorageDirectory();
Button encrypt = findViewById(R.id.zip);
Button dencrypt = findViewById(R.id.unzip);
progressBar = findViewById(R.id.progress);
encrypt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
progressBar.setVisibility(View.VISIBLE);
try {
Log.e("file", "try");
encryption();
} catch (Exception e) {
Log.e("file", "catch" + String.valueOf(e));
e.printStackTrace();
}
}
});
dencrypt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
progressBar.setVisibility(View.VISIBLE);
try {
dcryption();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
private void dcryption() throws Exception {
progressBar.setVisibility(View.VISIBLE);
String password = "javapapers";
// reading the salt
// user should have secure mechanism to transfer the
// salt, iv and password to the recipient
File fileSalt = new File(sdCardRoot, "/salt.enc");
FileInputStream saltFis = new FileInputStream(fileSalt);
byte[] salt = new byte[8];
saltFis.read(salt);
saltFis.close();
// reading the iv
File fileIv = new File(sdCardRoot, "/iv.enc");
FileInputStream ivFis = new FileInputStream(fileIv);
byte[] iv = new byte[16];
ivFis.read(iv);
ivFis.close();
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt, 65536,
256);
SecretKey tmp = factory.generateSecret(keySpec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
// file decryption
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
File oldFile = new File(sdCardRoot, "/wp.mp4");
File oldFile1 = new File(sdCardRoot, "/w.des");
FileInputStream fis = new FileInputStream(oldFile1);
FileOutputStream fos = new FileOutputStream(oldFile);
byte[] in = new byte[64];
int read;
while ((read = fis.read(in)) != -1) {
byte[] output = cipher.update(in, 0, read);
if (output != null)
fos.write(output);
}
byte[] output = cipher.doFinal();
if (output != null) {
fos.write(output);
fis.close();
fos.flush();
fos.close();
}
if (fileIv.exists() && fileSalt.exists() && oldFile1.exists()) {
fileIv.delete();
fileSalt.delete();
oldFile1.delete();
}
progressBar.setVisibility(View.GONE);
System.out.println("File Decrypted.");
}
private void encryption() throws Exception {
File oldFile = new File(sdCardRoot, "/w.mp4");
File oldFile1 = new File(sdCardRoot, "/w.des");
Log.e("file", String.valueOf(oldFile));
FileInputStream inFile = new FileInputStream(oldFile);
Log.e("file", String.valueOf(inFile));
// encrypted file
FileOutputStream outFile = new FileOutputStream(oldFile1);
Log.e("file", String.valueOf(outFile));
// password to encrypt the file
String password = "javapapers";
// password, iv and salt should be transferred to the other end
// in a secure manner
// salt is used for encoding
// writing it to a file
// salt should be transferred to the recipient securely
// for decryption
byte[] salt = new byte[8];
SecureRandom secureRandom = new SecureRandom();
secureRandom.nextBytes(salt);
Log.e("file", "a");
File fileSalt = new File(sdCardRoot, "/salt.enc");
FileOutputStream saltOutFile = new FileOutputStream(fileSalt);
Log.e("file", "b");
saltOutFile.write(salt);
saltOutFile.close();
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt, 65536,
256);
SecretKey secretKey = factory.generateSecret(keySpec);
SecretKey secret = new SecretKeySpec(secretKey.getEncoded(), "AES");
//
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
// iv adds randomness to the text and just makes the mechanism more
// secure
// used while initializing the cipher
// file to store the iv
Log.e("file", "c");
File fileIv = new File(sdCardRoot, "/iv.enc");
FileOutputStream ivOutFile = new FileOutputStream(fileIv);
Log.e("file", "d");
byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
ivOutFile.write(iv);
ivOutFile.close();
//file encryption
byte[] input = new byte[64];
int bytesRead;
while ((bytesRead = inFile.read(input)) != -1) {
byte[] output = cipher.update(input, 0, bytesRead);
if (output != null)
outFile.write(output);
}
byte[] output = cipher.doFinal();
if (output != null)
outFile.write(output);
inFile.close();
outFile.flush();
outFile.close();
if (oldFile.exists()) {
oldFile.delete();
}
System.out.println("File Encrypted.");
}

Use Below Code:
import java.io.File;
import java.io.RandomAccessFile;
public class VideoCrypt {
public static final int REVERSE_BYTE_COUNT = 1024;
public static boolean decrypt(String path) {
try {
if (path == null) return false;
File source = new File(path);
int byteToReverse = source.length() < REVERSE_BYTE_COUNT ? ((int) source.length()) : REVERSE_BYTE_COUNT;
RandomAccessFile f = new RandomAccessFile(source, "rw");
f.seek(0);
byte b[] = new byte[byteToReverse];
f.read(b);
f.seek(0);
reverseBytes(b);
f.write(b);
f.seek(0);
b = new byte[byteToReverse];
f.read(b);
f.close();
return true;
} catch (Exception e) {
return false;
}
}
public static boolean encrypt(String path) {
try {
if (path == null) return false;
File source = new File(path);
RandomAccessFile f = new RandomAccessFile(source, "rw");
f.seek(0);
int byteToReverse = source.length() < REVERSE_BYTE_COUNT ? ((int) source.length()) : REVERSE_BYTE_COUNT;
byte b[] = new byte[byteToReverse];
f.read(b);
f.seek(0);
reverseBytes(b);
f.write(b);
f.seek(0);
b = new byte[byteToReverse];
f.read(b);
f.close();
return true;
} catch (Exception e) {
return false;
}
}
private static void reverseBytes(byte[] array) {
if (array == null) return;
int i = 0;
int j = array.length - 1;
byte tmp;
while (j > i) {
tmp = array[j];
array[j] = array[i];
array[i] = tmp;
j--;
i++;
}
}
}

File types are identified by file extension and file magic. If you want to skip encrypting the file you can edit the file header by changing its magic so that programs can't recognize the type. A "magic" is a few bytes at the start of the file that define its type.

Android javax.crypto.BadPaddingException: pad block corrupted

I am trying to decrypt a file using the following code:
Uri targURI = Uri.parse("content://xxxx/yyy.txt");
try {
InputStream content = getContentResolver().openInputStream(targURI);
BufferedReader reader1 = new BufferedReader(new InputStreamReader(content));
String line1;
String text = "";
while ((line1 = reader1.readLine()) != null) {
text+=line1;
}
Log.i("FILE ENCRYPTED", text);
String DECRYPTED = "";
DECRYPTED = decrypt(text);
Log.i("FILE DECRYPTED:", DECRYPTED);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public String decrypt(String paramString) throws Exception {
String md5_pin1 = "";
String md5_pin = MD5(md5_pin1);
SecretKeySpec keySpec = new SecretKeySpec(md5_pin.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, keySpec);
byte[] paramString1 = Base64.decode(paramString.getBytes(), 0);
byte[] paramstring2 = cipher.doFinal(paramString1);
String decoded = new String(paramstring2, "UTF-8");
return decoded;
}
#NonNull
public static String MD5(String paramString) throws Exception {
MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
digest.update(paramString.getBytes());
byte messageDigest[] = digest.digest();
StringBuffer hexString = new StringBuffer();
int i=0;
while( i < messageDigest.length) {
String str = Integer.toHexString( messageDigest[i] & 0xFF );
if (str.length() == 1) {
hexString.append("0");
}
hexString.append(str);
i += 1;
}
return hexString.toString();
}
as it is showed the file is accessed using a content provider, and stored in a String variable, and actually the correct string value is stored (encrypted data).
The way to decrypt it is to get a seed (empty space in this case), and then use MD5 digest, then use that value to encrypt/decrypt the cleartext.
However whenever the code reaches: String decoded = new String(paramstring2, "UTF-8"); the error message: pad block corrupted is thrown.
Any ideas what I am doing wrong?

Avoid using default padding for cipher as it may be different on different environment.
Try the following code:
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
Also use the same padding for encrypting the file.
You can use the following methods:
private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] iv = new byte[cipher.getBlockSize()];
IvParameterSpec ivParams = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"), ivParams);
return cipher.doFinal(data);
}
private static byte[] decrypt(byte[] encrypted, byte[] key) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] ivByte = new byte[cipher.getBlockSize()];
IvParameterSpec ivParamsSpec = new IvParameterSpec(ivByte);
cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key, "AES"), ivParamsSpec);
return cipher.doFinal(encrypted);
}

This was not a problem related to coding.
Please disregard this question

javax.crypto.BadPaddingException: Given final block not properly padded while decryption

I am trying to decrypt a file in java. The first 16 bytes of decrypted file are IV (initialization vector). Please help in resolving the above exception.
I am trying to prepend the IV in the output file in AESFileEncryption() and then reading it while decryption.
Thank You.
public class AESFileEncryption {
public static void encrypt(String path,String pwd) throws Exception {
FileOutputStream outFile;
try (
FileInputStream inFile = new FileInputStream(path)) {
String fileName=path;
System.out.println(path);
outFile = new FileOutputStream(fileName+".aes");
// password to encrypt the file
String password = pwd;
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
};
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(password.toCharArray(),salt,65536,128);// user-chosen password that can be used with password-based encryption (PBE).
SecretKey secretKey = factory.generateSecret(keySpec);
SecretKey secret = new SecretKeySpec(secretKey.getEncoded(), "AES");//Secret KeySpec is a class and implements inteface SecretKey
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecureRandom random = new SecureRandom();
byte bytes[] = new byte[16];
random.nextBytes(bytes);
IvParameterSpec ivspec = new IvParameterSpec(bytes);
cipher.init(Cipher.ENCRYPT_MODE, secret,ivspec);//opmode,key
outFile.write(bytes);
byte[] input = new byte[64];
int bytesRead;
while ((bytesRead = inFile.read(input)) != -1) {
byte[] output = cipher.update(input, 0, bytesRead);
if (output != null)
Files.write(Paths.get(fileName+".aes"), output, StandardOpenOption.APPEND);
} byte[] output = cipher.doFinal();
if (output != null)
Files.write(Paths.get(fileName+".aes"), output, StandardOpenOption.APPEND);
}
outFile.flush();
outFile.close();
File f=new File(path);
boolean x=f.delete();
if(x){
System.out.println("File deleted");
}
JOptionPane.showMessageDialog(null,"File Encrypted.");
}
}
Decryption code
public class AESFileDecryption {
public static void decrypt(String path,String pwd) throws Exception {
String password = pwd;
String fileName=path;
File file=new File(path);
//System.out.println(inFile.toString());
String fileNameWithOutExt = path.replaceFirst("[.][^.]+$", "");
System.out.println(fileName);
System.out.println(fileNameWithOutExt);
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
};
System.out.println("1");
FileInputStream fis = new FileInputStream(path);
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(password.toCharArray(),salt,65536,128);
SecretKey tmp = factory.generateSecret(keySpec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
System.out.println("2");
// file decryption
Cipher cipher=null;
byte bytes[]=new byte[16];
fis.read(bytes, 0, 16);
IvParameterSpec ivspec = new IvParameterSpec(bytes);
cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secret, ivspec);
System.out.println("3");
FileOutputStream fos = new FileOutputStream(fileNameWithOutExt);
System.out.println("4");
byte[] in = new byte[64];
int read;
while ((read = fis.read(in,16,(int)file.length()-16)) != -1) {
byte[] output = cipher.update(in, 0, read);
if (output != null)
fos.write(output);
}
try{
byte[] output = cipher.doFinal();
if (output != null)
fos.write(output);
fis.close();
fos.flush();
fos.close();
System.out.println("File Decrypted.");
}
catch(IOException | BadPaddingException | IllegalBlockSizeException e)
{
System.out.println(e+"");
}
}
}

There are a few problems with the small example, but the one that is most immediately your problem is the line
while ((read = fis.read(in,16,(int)file.length()-16)) != -1) {
You seem to be confused about the meaning of the offset parameter to the read(). It is not the offset into the file, but rather the offset into the array (in) that is specified in the first parameter.
A non-exhaustive list of other problems that I see include:
writing to the file using the two independent mechanisms (FileOutputStream.write() and Files.write()). This actually worked ok when I ran your program but it seems like it's asking for trouble. There's no reason to use Files.write() here.
fis.read(bytes, 0, 16); does not check the return value.
It seems you are struggling with finding some IO idioms that you're comfortable with. Or perhaps just experimenting. At the risk of giving you even more options to juggle, you might consider investigating google's open source Guava library. Many people find it has just what they needed.

RSA - Encrypt in Android / Decrypt in PHP

I encrypt a word in java and I have trouble decrypting it in php.
here is how I create the keys in android:
public void GenerateAndSaveToFile(){
try {
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024);
KeyPair kp = kpg.genKeyPair();
Key publicKey = kp.getPublic();
Key privateKey = kp.getPrivate();
KeyFactory fact = KeyFactory.getInstance("RSA");
RSAPublicKeySpec pub = fact.getKeySpec(kp.getPublic(), RSAPublicKeySpec.class);
RSAPrivateKeySpec priv = fact.getKeySpec(kp.getPrivate(), RSAPrivateKeySpec.class);
//////////////////////////
String root = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES).toString();
File myDir = new File(root + "/keys");
myDir.mkdirs();
File file = new File (myDir, "private.key");
FileOutputStream fileout1 = new FileOutputStream(file);
ObjectOutputStream oout1 = new ObjectOutputStream(fileout1);
oout1.writeObject(priv.getModulus());
oout1.writeObject( priv.getPrivateExponent());
oout1.close();
///////////////////////
File file2 = new File (myDir, "public.key");
FileOutputStream fileout2 = new FileOutputStream(file2);
ObjectOutputStream oout2 = new ObjectOutputStream(new BufferedOutputStream(fileout2));
oout2.writeObject(pub.getModulus());
oout2.writeObject( pub.getPublicExponent());
oout2.close();
}
catch (Exception ex){
Exception e = ex;
}
}
here is how I encrypt the word with generated public key in android:
byte[] u1Encrypted = RSAEncrypt(String.valueOf(inputEmail.getText()).getBytes());
public byte[] RSAEncrypt(byte[] data) {
try {
PublicKey pubKey = ReadPublicKey();
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] cipherData = cipher.doFinal(data);
return cipherData;
}
catch (Exception ex)
{
Exception e = ex;
return null;
}
}
private PublicKey ReadPublicKey() throws IOException {
try {
AssetManager assetManager = getAssets();
InputStream in = assetManager.open("public.key");
ObjectInputStream oin = new ObjectInputStream(new BufferedInputStream(in));
try {
BigInteger m = (BigInteger) oin.readObject();
BigInteger e = (BigInteger) oin.readObject();
RSAPublicKeySpec keySpec = new RSAPublicKeySpec(m, e);
KeyFactory fact = KeyFactory.getInstance("RSA");
PublicKey pubKey = fact.generatePublic(keySpec);
return pubKey;
} catch (Exception e) {
throw new RuntimeException("Spurious serialisation error", e);
} finally {
oin.close();
}
}
catch (Exception ex)
{
Exception e = ex;
return null;
}
}
then I convert the encrypted string to base64 in android:
String u1EncryptedBase64 = Base64.encodeToString(u1Encrypted, Base64.DEFAULT);
and in php I decode the base64 string:
$encryptedString = base64_decode(u1EncryptedBase64);
get the private key:
$keytmp = fopen("../../../private.key", "r") or die("Unable to open file!");
$key = fread($keytmp,filesize("../../../private.key"));
$res = openssl_get_privatekey($key);
and finally I try to decrypt the string in php:
if (openssl_private_decrypt($encryptedString, $decrypted, $res)) {
echo $decrypted;
}
else
{
echo "problem";
}
and error I get is:
Warning: openssl_private_decrypt(): key parameter is not a valid private key ...
please guide me how to accompolish this task.
thanks

I can show you how i have done encryption in my android and decryption in php. It worked wonderfully fine.May be you can get some help from this. In android the code is like:
final private static String RSA_public_key="MIIBIDANBgkqhkiG9w0BAQEFAAOCAQ0AMIIBCAKCAQEApeRuOhn71+wcRtlN6JoW\n" +
"JLrVE5HKLPukFgpMdguNskBwDOPrrdYKP1e3rZMHN9oVB/QTTpkQM4CrGYlstUmT\n" +
"u5nEfdsH4lHRxe3qhi9+zOknWKJCnW4Cq70oITCAK08BIJ/4ZcGM1SUyv1+0u1aB\n" +
"cx6g1aKhthttRjNpck2LBaHVolt7Z4FTb5SdZMwJKRyEv8fuP6yyR0CJGEbQKZKA\n" +
"ODNKyqJ42sVzUQ2AMQIWdhkFdAFahKCL4MChGvKU6F20cHdvokyxXJjU3sZobjNf\n" +
"i+8FzH9hd7y8kmi4o3AKP69p5asgflXoXHpo135i3NzZqlNJ+Bs9pY+90u9iLScp\n" +
"JwIBAw==";
static String enccriptData(String txt)
{
String encoded = "";
byte[] encrypted = null;
try {
byte[] publicBytes = Base64.decode(RSA_public_key, Base64.DEFAULT);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING"); //or try with "RSA"
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
encrypted = cipher.doFinal(txt.getBytes());
encoded = Base64.encodeToString(encrypted, Base64.DEFAULT);
}
catch (Exception e) {
e.printStackTrace();
}
return encoded;
}
I have paste that encoded string that is returned in the above function in below $string. This is the code for php:
<?php
$string="W39VlV1Q96QzDIR/jINzaEL7rh2Z+Z90uxJ1DtaSfkVKzIgt2TIkxsuRY+A2icwPtTdq6+9j1Xb009KT+ck2KD+dot3wPL5UaHqApbZSi6UZan/nDbFCNJdffTlTWsPS2ThEefeMMSs8HE2ORSt42D8cxYlogOvkvlLr60cHYKwfC1itLSqPuYR+C/gPAf6yCteLbj//EkJp8TemlmPi0eSsH492FgrmBqiTOS4LzpzsPFpSI4KJbuM2dvqp5jkt7MnpR1laILmyC37fA5XPUQmEQChoG5eSbMxqO7SPboYC1BH9ATy6uTS1MGXGDzJ2FSJ41MMRV1Ul/4UNFVA8Ng==";
$encryptedString = base64_decode($string);
$key="-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----";
openssl_private_decrypt($encryptedString, $decrypted, $key);
$string1=$decrypted;
echo $string1;
?>
The private and public keys are made for each other.

Send file encrypted (Server) and receive file decrypted (Client) with AES 256

Im sending a file from Server to a Client but i need to send a encrypted file with AES 256 and receive a original for client use in diferente machine.
I want use 2 string to generate a SHA256 for example: "fruit" and "car29".
After generate this key I want to use this key as secretkey to encrypt with AES256.The client and server know the two strings.
My server code:
public final static int SOCKET_PORT = 4444;
public final static String FILE_TO_SEND = "C:\\file.txt";
public static void main(String[] args) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
FileInputStream fis = null;
BufferedInputStream bis = null;
OutputStream os = null;
ServerSocket servsock = null;
Socket sock = null;
try {
servsock = new ServerSocket(SOCKET_PORT);
while (true) {
System.out.println("Waiting...");
try {
sock = servsock.accept();
System.out.println("Accepted connection : " + sock);
// send file
File myFile = new File(FILE_TO_SEND);
byte[] mybytearray = new byte[(int) myFile.length()];
fis = new FileInputStream(myFile);
bis = new BufferedInputStream(fis);
bis.read(mybytearray, 0, mybytearray.length);
os = sock.getOutputStream();
System.out.println("Sending " + FILE_TO_SEND + "(" + mybytearray.length + " bytes)");
os.write(mybytearray, 0, mybytearray.length);
os.flush();
System.out.println("Done.");
} finally {
if (bis != null) {
bis.close();
}
if (os != null) {
os.close();
}
if (sock != null) {
sock.close();
}
}
}
} finally {
if (servsock != null) {
servsock.close();
}
}
}
My client code:
public final static int SOCKET_PORT = 4444;
public final static String SERVER = "127.0.0.1";
public final static String FILE_TO_RECEIVED = "C:\\file.txt";
public final static int FILE_SIZE = 6022386;
public static void main (String [] args ) throws IOException {
int bytesRead;
int current = 0;
FileOutputStream fos = null;
BufferedOutputStream bos = null;
Socket sock = null;
try {
sock = new Socket(SERVER, SOCKET_PORT);
System.out.println("Connecting...");
// receive file
byte [] mybytearray = new byte [FILE_SIZE];
InputStream is = sock.getInputStream();
fos = new FileOutputStream(FILE_TO_RECEIVED);
bos = new BufferedOutputStream(fos);
bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead;
do {
bytesRead =
is.read(mybytearray, current, (mybytearray.length-current));
if(bytesRead >= 0) current += bytesRead;
} while(bytesRead > -1);
bos.write(mybytearray, 0 , current);
bos.flush();
System.out.println("File " + FILE_TO_RECEIVED
+ " downloaded (" + current + " bytes read)");
}
finally {
if (fos != null) fos.close();
if (bos != null) bos.close();
if (sock != null) sock.close();
}
}
Thanks in advance!

There's some function I write for you, check it out.
For generating HASH/Digest:
public byte[] generateHASH(byte[] message) throws Exception {
MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
byte[] hash = messageDigest.digest(message);
return hash;
}
For Encryption:
public byte[] encrypt(byte[] msg, byte[] key, byte[] iv) throws Exception {
//prepare key
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
//prepare cipher
String cipherALG = "AES/CBC/PKCS5padding"; // use your preferred algorithm
Cipher cipher = Cipher.getInstance(cipherALG);
String string = cipher.getAlgorithm();
//as iv (Initial Vector) is only required for CBC mode
if (string.contains("CBC")) {
IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
} else {
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
}
byte[] encMessage = cipher.doFinal(msg);
return encMessage;
}
For Decryption:
public byte[] decrypt(byte[] encMsgtoDec, byte[] key, byte[] iv) throws Exception {
//prepare key
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
//prepare cipher
String cipherALG = "AES/CBC/PKCS5padding"; // use your preferred algorithm
Cipher cipher = Cipher.getInstance(cipherALG);
String string = cipher.getAlgorithm();
//as iv (Initial Vector) is only required for CBC mode
if (string.contains("CBC")) {
IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
} else {
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
}
byte[] decMsg = cipher.doFinal(encMsgtoDec);
return decMsg;
}
Note:
If you use CBC mode, then both encrypt() and decrypt() use same iv, otherwise you don't need iv, and of course key is same for both.
Your key generation process is naive. You better use RSA public key encryption for key exchange or Diffie–Hellman key exchange method for secret key transfer.

I would suggest you to use SSL. The data encryption comes by default. The SSL handshake takes care of generating and exchanging the encryption keys and subsequently encrypting the data from the source and decrypting it at the receiving end. All this happens at the transport layer and the application does not have to bother or do anything explicit except for configuring it to use SSL.