Till kitkat, encryption/decryption is working good but in lollipop it decrypts only partial data.
I don't have problem with encryption because I encrypted a file with lollipop and decrypts it with kitkat it works fine but not vice versa.
Here is the code.
Encryption code
Encrypt(BufferedInputStream is, File destfile, String passcode) {
bis = is;
try {
fos = new FileOutputStream(destfile);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
dest = new BufferedOutputStream(fos, 1024);
this.passcode = passcode;
}
static void encrypt() throws IOException, NoSuchAlgorithmException,
NoSuchPaddingException, InvalidKeyException {
// Length is 16 byte
SecretKeySpec sks = new SecretKeySpec(passcode.getBytes(), "AES");
// Create cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, sks);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[1024];
while ((b = bis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
bis.close();
}
Decryption code
public Decrypt(String path, String pathcode) {
// TODO Auto-generated constructor stub
filepath = path;
try {
fis = new FileInputStream(new File(path));
this.passcode = pathcode;
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
static String decrypt() throws IOException, NoSuchAlgorithmException,
NoSuchPaddingException, InvalidKeyException {
SecretKeySpec sks = new SecretKeySpec(passcode.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, sks);
CipherInputStream cis = new CipherInputStream(fis, cipher);
int size = fis.available();
byte[] resdata = new byte[size];
cis.read(resdata, 0, size);
String newres = new String(resdata, "UTF-8").trim();
//write("decrypted_file.xhtml",newres);
if(fis!=null)
{
fis.close();
}
if(cis!=null)
cis.close();
return newres;
}
What's the problem in this code? Do I need to do anything more?
available() doesn't necessarily return the length of the entire stream, just the estimated number of bytes that can be read without blocking. So, use a ByteArrayOutputStream to store the bytes and then covert to a byte array:
CipherInputStream cis = new CipherInputStream(fis, cipher);
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
int bytesRead;
byte[] data = new byte[1024];
while ((bytesRead = cis.read(data, 0, data.length)) != -1) {
buffer.write(data, 0, bytesRead);
}
buffer.flush();
byte[] resdata = buffer.toByteArray();
String newres = new String(resdata, "UTF-8").trim();
Related
I am trying to encrypt and then decrypt audio file . Everything goes right but when I try to decrypt the encrypted audio , everytime I got this exception
javax.crypto.BadPaddingException: pad block corrupted
My MainActivity is like this: I want to decrypt and play the song side by side
public class MainActivity extends Activity{
private final String KEY = "abc";
Button btn_Dec, btn_In;
byte[] incrept;
byte[] decrpt;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ctx = this;
btn_Dec = (Button) findViewById(R.id.button2);
btn_In = (Button) findViewById(R.id.button1);
btn_Dec.setOnClickListener(btnDecListner);
btn_In.setOnClickListener(btnInListner);
}
public OnClickListener btnDecListner = new OnClickListener() {
public void onClick(View v) {
VincentFileCrypto simpleCrypto = new VincentFileCrypto();
try {
// decrypt the file here first argument is key and second is encrypted file which we get from SD card.
decrpt = simpleCrypto.decrypt(KEY, getAudioFileFromSdCard());
//play decrypted audio file.
playMp3(decrpt);
} catch (Exception e) {
e.printStackTrace();
}
}
};
Context ctx;
public OnClickListener btnInListner = new OnClickListener() {
public void onClick(View v) {
VincentFileCrypto simpleCrypto = new VincentFileCrypto();
try {
// encrypt audio file send as second argument and corresponding key in first argument.
incrept = simpleCrypto.encrypt(KEY, getAudioFile());
//Store encrypted file in SD card of your mobile with name vincent.mp3.
FileOutputStream fos = new FileOutputStream(new File("/sdcard/vincent.mp3"));
fos.write(incrept);
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
};
/**
* #return byte array for encryption.
* #throws FileNotFoundException
*/
public byte[] getAudioFile() throws FileNotFoundException
{
byte[] audio_data = null;
byte[] inarry = null;
AssetManager am = ctx.getAssets();
try {
InputStream is = am.open("Sleep Away.mp3"); // use recorded file instead of getting file from assets folder.
int length = is.available();
audio_data = new byte[length];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
while ((bytesRead = is.read(audio_data)) != -1)
{
output.write(audio_data, 0, bytesRead);
}
inarry = output.toByteArray();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return inarry;
}
/**
* This method fetch encrypted file which is save in sd card and convert it in byte array after that this file will be decrept.
*
* #return byte array of encrypted data for decription.
* #throws FileNotFoundException
*/
public byte[] getAudioFileFromSdCard() throws FileNotFoundException
{
byte[] inarry = null;
try {
//getting root path where encrypted file is stored.
File sdcard = Environment.getExternalStorageDirectory();
File file = new File(sdcard, "vincent.mp3"); //Creating file object
//Convert file into array of bytes.
FileInputStream fileInputStream = null;
byte[] bFile = new byte[(int) file.length()];
fileInputStream = new FileInputStream(file);
fileInputStream.read(bFile);
fileInputStream.close();
inarry = bFile;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return inarry;
}
/**
* This Method is used to play audio file after decrepting.
*
* #param mp3SoundByteArray : This is our audio file which will be play and it converted in byte array.
*/
private void playMp3(byte[] mp3SoundByteArray) {
try {
// create temp file that will hold byte array
File tempMp3 = File.createTempFile("kurchina", "mp3", getCacheDir());
tempMp3.deleteOnExit();
FileOutputStream fos = new FileOutputStream(tempMp3);
fos.write(mp3SoundByteArray);
fos.close();
// Tried reusing instance of media player
// but that resulted in system crashes...
MediaPlayer mediaPlayer = new MediaPlayer();
FileInputStream fis = new FileInputStream(tempMp3);
mediaPlayer.setDataSource(fis.getFD());
mediaPlayer.prepareAsync();
mediaPlayer.start();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
The encryption and decryption methods are mentioned in this class
public class VincentFileCrypto {
public byte[] encrypt(String seed, byte[] cleartext) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes());
byte[] result = encrypt(rawKey, cleartext);
// return toHex(result);
return result;
}
public byte[] decrypt(String seed, byte[] encrypted) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes());
byte[] enc = encrypted;
byte[] result = decrypt(rawKey, enc);
return result;
}
//done
private byte[] getRawKey(byte[] seed) throws Exception {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(seed);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
return raw;
}
private byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(clear);
return encrypted;
}
private byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encrypted);
return decrypted;
}
}
After days of research and hard work I found the solution ,may help and save somebody's else time . Here is my answer. I changed the above code logic like this
now what is happening , I am able to successfully encrypt the file and save it in the sdcard and then decrypt it to play . No body else can play the audio.
here we go : happy coding
public class Main2Activity extends AppCompatActivity {
private String encryptedFileName = "encrypted_Audio.mp3";
private static String algorithm = "AES";
static SecretKey yourKey = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
//saveFile("Hello From CoderzHeaven asaksjalksjals");
try {
saveFile(getAudioFile());
} catch (FileNotFoundException e) {
e.printStackTrace();
}
decodeFile();
}
public static SecretKey generateKey(char[] passphraseOrPin, byte[] salt) throws NoSuchAlgorithmException, InvalidKeySpecException {
// Number of PBKDF2 hardening rounds to use. Larger values increase
// computation time. You should select a value that causes computation
// to take >100ms.
final int iterations = 1000;
// Generate a 256-bit key
final int outputKeyLength = 256;
SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(passphraseOrPin, salt, iterations, outputKeyLength);
SecretKey secretKey = secretKeyFactory.generateSecret(keySpec);
return secretKey;
}
public static SecretKey generateKey() throws NoSuchAlgorithmException {
// Generate a 256-bit key
final int outputKeyLength = 256;
SecureRandom secureRandom = new SecureRandom();
// Do *not* seed secureRandom! Automatically seeded from system entropy.
KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
keyGenerator.init(outputKeyLength, secureRandom);
yourKey = keyGenerator.generateKey();
return yourKey;
}
public static byte[] encodeFile(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] encrypted = null;
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length, algorithm);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(
new byte[cipher.getBlockSize()]));
encrypted = cipher.doFinal(fileData);
return encrypted;
}
public static byte[] decodeFile(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] decrypted = null;
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.DECRYPT_MODE, yourKey, new IvParameterSpec(new byte[cipher.getBlockSize()]));
decrypted = cipher.doFinal(fileData);
return decrypted;
}
void saveFile(byte[] stringToSave) {
try {
File file = new File(Environment.getExternalStorageDirectory() + File.separator, encryptedFileName);
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
yourKey = generateKey();
byte[] filesBytes = encodeFile(yourKey, stringToSave);
bos.write(filesBytes);
bos.flush();
bos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
void decodeFile() {
try {
byte[] decodedData = decodeFile(yourKey, readFile());
// String str = new String(decodedData);
//System.out.println("DECODED FILE CONTENTS : " + str);
playMp3(decodedData);
} catch (Exception e) {
e.printStackTrace();
}
}
public byte[] readFile() {
byte[] contents = null;
File file = new File(Environment.getExternalStorageDirectory()
+ File.separator, encryptedFileName);
int size = (int) file.length();
contents = new byte[size];
try {
BufferedInputStream buf = new BufferedInputStream(
new FileInputStream(file));
try {
buf.read(contents);
buf.close();
} catch (IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return contents;
}
public byte[] getAudioFile() throws FileNotFoundException
{
byte[] audio_data = null;
byte[] inarry = null;
AssetManager am = getAssets();
try {
InputStream is = am.open("Sleep Away.mp3"); // use recorded file instead of getting file from assets folder.
int length = is.available();
audio_data = new byte[length];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
while ((bytesRead = is.read(audio_data)) != -1) {
output.write(audio_data, 0, bytesRead);
}
inarry = output.toByteArray();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return inarry;
}
private void playMp3(byte[] mp3SoundByteArray) {
try {
// create temp file that will hold byte array
File tempMp3 = File.createTempFile("kurchina", "mp3", getCacheDir());
tempMp3.deleteOnExit();
FileOutputStream fos = new FileOutputStream(tempMp3);
fos.write(mp3SoundByteArray);
fos.close();
// Tried reusing instance of media player
// but that resulted in system crashes...
MediaPlayer mediaPlayer = new MediaPlayer();
FileInputStream fis = new FileInputStream(tempMp3);
mediaPlayer.setDataSource(fis.getFD());
mediaPlayer.prepare();
mediaPlayer.start();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
Hi I am working on AES encryption and decryption in my project.
I have a .mp4 file which is encrypted using "AES/CBC/pkcs5padding".
I have the key and iv values which is used to encrypt the first 256 bytes of the audio file.
I need to decrypt the file's first 256 bytes using the same algorithm , key and iv values.
I have followed some links (link1,link2).
I got a audio player demo and tried to implement my part(AES encryption and decryption) as demo.
Below I explained the code what I have done.
This method reads the data from encrypted file which is under res/raw folder.
private void readFile() throws IOException, InvalidKeyException,
NoSuchAlgorithmException, NoSuchPaddingException,
InvalidAlgorithmParameterException, IllegalBlockSizeException,
BadPaddingException {
Context context = getApplicationContext();
/*
* InputStream is = getResources().openRawResource(
* getResources().getIdentifier("raw/encrypted", "raw",
* getPackageName())); String text = "";
*
* int size = is.available(); byte[] buffer = new byte[size];
* is.read(buffer);
*/
InputStream inStream = context.getResources().openRawResource(
R.raw.encrypted);
// get string from file
byte[] music = new byte[256];
for (int i = 0; i <= inStream.available(); i = i + 255) {
music = convertStreamToByteArray(inStream, i);
byte[] bytesToWrite = new byte[256];
bytesToWrite = music;
if (i == 0) {
bytesToWrite = AES256Cipher.decrypt(iv.getBytes("UTF-8"),
key.getBytes("UTF-8"), music);
// writeFirstSetOfBytes("decrypted.mp4");
}
writeFirstSetOfBytes(bytesToWrite);
}
}
the decrypt method got from the link1. Here I passed the key and iv values mentioned above.
public static byte[] decrypt(byte[] ivBytes, byte[] keyBytes,
byte[] textBytes) throws java.io.UnsupportedEncodingException,
NoSuchAlgorithmException, NoSuchPaddingException,
InvalidKeyException, InvalidAlgorithmParameterException,
IllegalBlockSizeException, BadPaddingException {
AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivBytes);
// SecretKeySpec newKey = new SecretKeySpec(keyBytes, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE,
new SecretKeySpec(keyBytes, "AES"), ivSpec);
return cipher.doFinal(textBytes);
}
This method used to get the byte array from the input stream.
public static byte[] convertStreamToByteArray(InputStream is, int size)
throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buff = new byte[256];
int i = Integer.MAX_VALUE;
while ((i = is.read(buff, size, buff.length)) > 0) {
baos.write(buff, 0, i);
}
return baos.toByteArray(); // be sure to close InputStream in calling
// function
}
This method writes the received byte array into a destination file(decrypted.mp4)
private void writeFirstSetOfBytes(byte[] byteToWrite) {
File file = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS),
"/decrypted.mp4");
FileOutputStream stream = null;
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// writing data into file
try {
stream = new FileOutputStream(file);
stream.write(byteToWrite);
stream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I am getting the following error.
javax.crypto.IllegalBlockSizeException: error:0606506D:digital envelope routines:EVP_DecryptFinal_ex:wrong final block length
How can I achieve my requirement ?
How do I decrypt the first 256 bytes of data only?
Is there any code behaves wrongly ?
Is there any third party library avilable ?
If need more clarification, kindly let me know.
According to Wikipedia, PKCS#5 is a special variant of PKCS#7 that is defined for exactly 64-bit blocks (while PKCS#7 works for any block size), but AES uses 128-bit blocks only (or larger, but this was not included in the standard), thus the mismatch. Try another padding scheme.
I Tried following code.
How to read encrypted .epub file (Without saving decrypted file on sd card)
I want to maintain security for .epub file
is it possible to maintain security?
Thanks for Help in prior
static void encrypt() throws IOException, NoSuchAlgorithmException,
NoSuchPaddingException, InvalidKeyException {
// Here you read the cleartext.
String file_en_path = Environment.getExternalStorageDirectory().getAbsolutePath() +"/Decrypted";
File extStore = new File(file_en_path,"text.epub");
FileInputStream fis = new FileInputStream(extStore);
// This stream write the encrypted text. This stream will be wrapped by
// another stream.
File extStore_enc = new File(file_en_path,"text_enc.epub");
FileOutputStream fos = new FileOutputStream(extStore_enc);
Log.d("encrypt--fis------------->>>>>>",""+fis);
Log.d("encrypt--fos------------->>>>>>",""+fos);
// Length is 16 byte
SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(),"AES");
// Create cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, sks);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
}
static void decrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
String file_de_path = Environment.getExternalStorageDirectory().getAbsolutePath() +"/Decrypted";
File extStore = new File(file_de_path,"text_enc.epub");
//File extStore = Environment.getExternalStorageDirectory();
FileInputStream fis = new FileInputStream(extStore);
File extStore_dec = new File(file_de_path,"text_dec.epub");
FileOutputStream fos = new FileOutputStream(extStore_dec);
//FileOutputStream fos = context.openFileOutput("fontsize_dec.txt",Context.MODE_PRIVATE);
Log.d("decrypt--fis------------->>>>>>",""+fis);
Log.d("decrypt--fos------------->>>>>>",""+fos);
SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(),"AES");
IvParameterSpec ivSpec = new IvParameterSpec("MyDifficultPassw".getBytes());
Cipher cipher = Cipher.getInstance("AES");
try {
cipher.init(Cipher.DECRYPT_MODE, sks, ivSpec);
} catch (InvalidAlgorithmParameterException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
CipherInputStream cis = new CipherInputStream(fis, cipher);
int b;
byte[] d = new byte[8];
StringBuilder sb = new StringBuilder();
String line;
BufferedReader reader = new BufferedReader(new InputStreamReader(cis, "UTF-8"));
/*line = reader.readLine();
sb.append(line);
Log.d("sb.append(line)--------------------------->",""+sb.append(line));*/
while ((line = reader.readLine()) != null) {
sb.append(line);
// Log.d("sb.append(line)--------------------------->",""+sb.append(line));
// Log.d("Line--------------------------->",""+line);
}
Log.d("sb.toSting-------------------->",""+sb.toString());
while ((b = cis.read(d)) != -1) {
//Log.d("cis.read(d)------------------------>>>>>>>",""+cis.read(d));
fos.write(d, 0, b);
}
fos.flush();
fos.close();
cis.close();
}
I've never worked with encryption before. Actually I know nothing about encryption. I have a file encrypted with openssl tool using params:
openssl aes-256-cbc -nosalt -in fileIn -out fileOUT -p -k KEY
I need to decrypt it into memory but I don't know how. Can anyone provide me the code related to encryption?
Here's class I have written to decrypt a string encoded with params above (if I remmeber it correct):
public class CipherUtils {
public static byte[] getKey(String password, byte[] salt) {
try {
byte[] passwordSalt = EncodingUtils.getAsciiBytes(password);
passwordSalt = concatenateByteArrays(passwordSalt, salt);
byte[] hash1 = getHashForHash(null, passwordSalt);
byte[] hash2 = getHashForHash(hash1, passwordSalt);
byte[] key = concatenateByteArrays(hash1, hash2);
return key;
} catch (Exception e) {
return null;
}
}
public static byte[] getIV(String password, byte[] salt) {
try {
byte[] passwordSalt = EncodingUtils.getAsciiBytes(password);
passwordSalt = concatenateByteArrays(passwordSalt, salt);
byte[] hash1 = getHashForHash(null, passwordSalt);
byte[] hash2 = getHashForHash(hash1, passwordSalt);
byte[] hash3 = getHashForHash(hash2, passwordSalt);
return hash3;
} catch (Exception e) {
return null;
}
}
private static byte[] getHashForHash(byte[] hash, byte[] passwordSalt) {
try {
byte[] hashMaterial = concatenateByteArrays(hash, passwordSalt);
MessageDigest md = MessageDigest.getInstance("MD5");
return md.digest(hashMaterial);
} catch (Exception e) {
return null;
}
}
private static byte[] concatenateByteArrays(byte[] a, byte[] b) {
if (a == null)
return b;
if (b == null)
return a;
byte[] result = new byte[a.length + b.length];
System.arraycopy(a, 0, result, 0, a.length);
System.arraycopy(b, 0, result, a.length, b.length);
return result;
}
}
Salt is an empty bytearray in this case. It uses apache-commons-compress.jar.
Here's usage example:
byte[] key = CipherUtils.getKey(password, null);
byte[] IV = CipherUtils.getIV(password, null);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key, "AES"),
new IvParameterSpec(IV));
cis = new CipherInputStream(is, cipher);
Where is is an InputStream of encrypted data.
this may helps you
public void encrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
// Here you read the cleartext.
FileInputStream fis = new FileInputStream("data/cleartext");
// This stream write the encrypted text. This stream will be wrapped by
// another stream.
FileOutputStream fos = new FileOutputStream("data/encrypted");
// Length is 16 byte
SecretKeySpec sks = new SecretKeySpec("yourkey".getBytes(), "AES");
// Create cipher
Cipher cipher = Cipher.getInstance("AES/CBC");
cipher.init(Cipher.ENCRYPT_MODE, sks);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
}
Decrypt
public void decrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
FileInputStream fis = new FileInputStream("data/encrypted");
FileOutputStream fos = new FileOutputStream("data/decrypted");
SecretKeySpec sks = new SecretKeySpec("yourkey".getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC");
cipher.init(Cipher.DECRYPT_MODE, sks);
CipherInputStream cis = new CipherInputStream(fis, cipher);
int b;
byte[] d = new byte[8];
while((b = cis.read(d)) != -1) {
fos.write(d, 0, b);
}
fos.flush();
fos.close();
cis.close();
}
I am working on some big files and when I will go for the full file encryption/decryption. It is taking too much of time. Now I want to encrypt only first 1024 bytes of file and the rest of the bytes will remain the same.
Here is my code:
static void encrypt(String inputPath, String outputPath) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException
{
// Here you read the cleartext.
FileInputStream fis = new FileInputStream(inputPath);
// This stream write the encrypted text. This stream will be wrapped by another stream.
FileOutputStream fos = new FileOutputStream(outputPath);
// Length is 16 byte
SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(), "AES");
// Create cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, sks);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
int count = 0;
byte[] d = new byte[1024];
while((b = fis.read(d)) != -1) {
if(count <= 1024){
count += b;
cos.write(d, 0, b);
}else{
cos.write(d, 0, b);
}
// cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
}
static byte[] decrypt(String inputPath) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
FileInputStream fis = new FileInputStream(inputPath);
// FileOutputStream fos = new FileOutputStream(outputPath);
SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, sks);
CipherInputStream cis = new CipherInputStream(fis, cipher);
int b;
byte[] d = new byte[1024];
ByteArrayOutputStream bos = new ByteArrayOutputStream();
int count =0;
while((b = cis.read(d)) != -1) {
if(count <= 1024){
count += b;
bos.write(d, 0, b);
}else{
bos.write(d, 0, b);
}
}
byte[] completeBytes = bos.toByteArray();
cis.close();
return completeBytes;
}
Please suggest something..
load the first 1024 bytes from the file, encrypt them then write them back. convert this C# code to java for reading the first 1024 bytes:
byte[] chunkData = new byte[];
int chunkSize = 1024;
using(FileStream fsInput = FileStream(PATH TO FileMode.Read)
fsInput.Read(chunkData, 0, chunkSize);