Develop Reference

Android javax.crypto.BadPaddingException

I am implementing encryption/decryption to my files. code is given below. I can't find out the problem.
Am I missing anything? I need to implement 128 bit AES Encryption.
Is there anything wrong?
It end up with error
"javax.crypto.BadPaddingException: error:1e06b065:Cipher functions:EVP_DecryptFinal_ex:BAD_DECRYPT"
Please help me.
private static byte[] encodeFile(byte[] yourKey, byte[] fileData)
throws Exception {
byte[] encrypted = null;
SecretKeySpec skeySpec = new SecretKeySpec(yourKey, 0, yourKey.length, "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7PADDING");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
encrypted = cipher.doFinal(fileData);
return encrypted;
}
private static byte[] generateKey() throws NoSuchAlgorithmException {
byte[] keyStart = "This is my key".getBytes();
String id = "dummypass";
int iterationCount = 1000;
int saltLength = 32;
int keyLength = 128;
SecureRandom random = new SecureRandom();
byte[] salt = Arrays.copyOf(keyStart,saltLength);
random.nextBytes(salt);
KeySpec keySpec = new PBEKeySpec(id.toCharArray(), salt,
iterationCount, keyLength);
SecretKeyFactory keyFactory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
byte[] keyBytes = new byte[0];
try {
keyBytes = keyFactory.generateSecret(keySpec).getEncoded();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
SecretKey key = new SecretKeySpec(keyBytes, "AES");
return key.getEncoded();
}
private static byte[] decodeFile(byte[] yourKey, byte[] encryptedData)
throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(yourKey, 0, yourKey.length,
"AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7PADDING");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encryptedData);
return decrypted;
}
public static void Encrypt(byte[] bytesToEncrypt, File target) {
try {
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream(target));
byte[] key = generateKey();
byte[] encryptedBytes = encodeFile(key, bytesToEncrypt);
bos.write(encryptedBytes);
bos.flush();
bos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public static byte[] DecryptFile(byte[] bytesToDecrypt) {
byte[] decodedData = new byte[0];
try {
byte[] key = generateKey();
decodedData = decodeFile(key, bytesToDecrypt);
} catch (Exception e) {
e.printStackTrace();
}
return decodedData;
}

Verify that key is the same in both Encrypt and DecryptFile.
Since both call generateKey and generateKey calls SecureRandom nextBytes the keys are going to be different.
You need to save the encryption key for use during decryption.

Android Lollipop Decryption using AES is not working properly

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();

Decryption of pdf file in android

I need to encrypt and decrypt the PDF file which is in external storage and did encryption using AES algorithm.
Now i need to decrypt the file which as encrypted,tried to decrypt and get byte then convert to string to show in textview but it showing data in encrypted form in textview...
Code is here which i tried:
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;
public class FileActivity extends Activity {
private String encryptedFileName = "sample.pdf.aes";//
private static String algorithm = "AES";
static SecretKey yourKey = null;
TextView text;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file);
// saveFile("Hi friends");
try {
saveFile( new String(loadFile(Environment.getExternalStorageDirectory()+"/pdf.pdf")));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
text=(TextView)findViewById(R.id.text);
text.setText(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);
yourKey = secretKeyFactory.generateSecret(keySpec);
return yourKey;
}
public static SecretKey generateSalt() 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);
SecretKey key = keyGenerator.generateKey();
return key;
}
public static byte[] encodeFile(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length,
algorithm);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(fileData);
return encrypted;
}
public static byte[] decodeFile(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length,
algorithm);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(fileData);
return decrypted;
}
void saveFile(String stringToSave) {
try {
File file = new File(Environment.getExternalStorageDirectory()
+ File.separator, encryptedFileName);
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream(file));
char[] p = { 'p', 'a', 's', 's' };
SecretKey yourKey = generateKey(p, generateSalt().toString()
.getBytes());
byte[] filesBytes = encodeFile(yourKey, stringToSave.getBytes());
bos.write(filesBytes);
bos.flush();
bos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public static byte[] loadFile(String sourcePath) throws IOException
{
InputStream inputStream = null;
try
{
inputStream = new FileInputStream(sourcePath);
return readFully(inputStream);
}
finally
{
if (inputStream != null)
{
inputStream.close();
}
}
}
public static byte[] readFully(InputStream stream) throws IOException
{
byte[] buffer = new byte[8192];
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int bytesRead;
while ((bytesRead = stream.read(buffer)) != -1)
{
baos.write(buffer, 0, bytesRead);
}
return baos.toByteArray();
}
String decodeFile() {
String str = null;
try {
byte[] decodedData = decodeFile(yourKey,loadFile(Environment.getExternalStorageDirectory()+"/sample.pdf.aes"));
str = new String(decodedData);
System.out.println("DECODED FILE CONTENTS : " + str);
} catch (Exception e) {
e.printStackTrace();
}
return str;
}
}
Thanks if any suggestions is great help....Is there any another way to do encrypt and decrypt the pdf file

I got with this code
public class FileActivity extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file);
encryptPDF();
}
public void encryptPDF()
{
//CipherInputStream input=null;
/*FileInputStream fis=null ;
FileOutputStream fos=null;*/
// get the key
try {
final KeyGenerator generator = KeyGenerator.getInstance("AES");
generator.init(128);
final SecretKey secretKey = generator.generateKey();
// perform encryption
Cipher cipher;
cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretKey);
FileInputStream fis = new FileInputStream(Environment.getExternalStorageDirectory()+"/sample.pdf");
FileOutputStream fos = new FileOutputStream(Environment.getExternalStorageDirectory()+"/pdf_encrypt.enc");
final CipherOutputStream output = new CipherOutputStream(fos, cipher);
int bytesRead = 0;
final byte[] plainText = new byte[4096];
while ((bytesRead = fis.read(plainText)) >= 0) {
output.write(plainText, 0, bytesRead);
}
output.flush();
output.close();
fos.close();
fis.close();
final byte[] iv = cipher.getIV();
// decrypt the file
cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(iv));
fis = new FileInputStream(Environment.getExternalStorageDirectory()+"/pdf_encrypt.enc");
fos = new FileOutputStream(Environment.getExternalStorageDirectory()+"/test.pdf");
CipherInputStream input = new CipherInputStream(fis, cipher);
final byte[] decryptedData = new byte[4096];
int decryptedRead;
while ((decryptedRead = input.read(decryptedData)) >= 0) {
fos.write(decryptedData, 0, decryptedRead);
}
fos.flush();
fos.close();
input.close();
fis.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

Decrypt AES256 encrypted bytes

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();
}

How to download an encrypted png file without loosing data?

I'm new to android. I'm doing an application which can download an encrypted png image file to sd card then displaying it after decryption. But I notice that I'm getting "javax.crypto.IllegalBlockSizeException: last block incomplete in decryption image decryption" when decrypting that downloaded image. Then I found that downloaded image size is 0KB (Original - 150KB). Then I downloaded my encrypted image from browser and checked. I'm getting the original image size. I'm sure there is something wrong in my image downloading class. But I cant figure it out. Please help me. Thanks in advance.
Image downloading AsyncTask Class
public class DownloadImagesTask extends AsyncTask<String, Void, Bitmap>
{
private String fileName;
#Override
protected Bitmap doInBackground(String... urls)
{
//Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
return download_Image(urls[0]);
}
#Override
protected void onPostExecute(Bitmap result)
{
storeImage(result);
}
private Bitmap download_Image(String url)
{
Bitmap bm = null;
File file = new File(url);
fileName = file.getName();
try
{
URL aURL = new URL(url);
URLConnection conn = aURL.openConnection();
conn.connect();
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
bm = BitmapFactory.decodeStream(bis);
bis.close();
is.close();
}
catch (OutOfMemoryError e)
{
Log.e("Hub", "Error getting the image from server : " + e.getMessage().toString());
}
catch (IOException e)
{
Log.e("Hub", "Error getting the image from server : " + e.getMessage().toString());
}
return bm;
}
public void storeImage(Bitmap bm)
{
BitmapFactory.Options bmOptions;
bmOptions = new BitmapFactory.Options();
bmOptions.inSampleSize = 1;
String extStorageDirectory = CommonUtils.getDataFromPreferences("metaPath", "");
Log.d("extStorageDirectory", extStorageDirectory);
OutputStream outStream = null;
File wallpaperDirectory = new File(extStorageDirectory);
if (!wallpaperDirectory.exists())
{
wallpaperDirectory.mkdirs();
}
File outputFile = new File(wallpaperDirectory, fileName);
if (!outputFile.exists() || outputFile.length() == 0)
{
try
{
outStream = new FileOutputStream(outputFile);
}
catch (FileNotFoundException e1)
{
e1.printStackTrace();
}
try
{
bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
outStream.flush();
outStream.close();
Log.d("ScratchActivtiy", "Image Saved");
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
}
(All images were encrypted by me. And I hosted them in a Server. There is no issue in ancryption or decryption. I tested them. All are working fine.)
CryptClass
public class CryptClass
{
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);
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;
}
}

If I understand correctly you are downloading the image first
BufferedInputStream bis = new BufferedInputStream(is);
bm = BitmapFactory.decodeStream(bis);
Then saving it to a file with PNG compression:
bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
And AFTER that doing your decryption on the file, right?
I think you might want to decrypt the bytes prior to saving them as a png, or maybe even prior to using the decodeStream. Otherwise you are decrypting the encrypted bytes that decode stream and PNG compression messed with.
Try skipping all of the BitmapFactory stuff and just save the initial file as-is, and then run your decryption. In your AsyncTask:
String saveFilePath = <path to the temporary encrypted file>;
FileOutputStream outputStream = new FileOutputStream(saveFilePath);
int bytesRead = -1;
byte[] buffer = new byte[4096];
while ((bytesRead = is.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.close();
inputStream.close();
Then run your decryption stuff on the saved file