Develop Reference

CryptoKit-ios and Android encrypting and decrypting

I am trying to encrypt in android and decrypt in ios.I am using AES.GCM encryption however when i try to decrypt the package in ios i get Aunthetication faliure message.Below is the code for ios decryption
func decryptData(decryptToData:Data,key:SymmetricKey)->String {
let combinedData = decryptToData // Previous sealed bo
let sealedBoxToOpen = try! AES.GCM.SealedBox(combined: decryptToData)
if let decryptedData = try? AES.GCM.open(sealedBoxToOpen, using: key) {
decryptedString = String(data: decryptedData, encoding: .utf8)!
print(decryptedString ?? "Failed")
} else {
print(CryptoKitError) // Ouch, doSomething() threw an error.
}
}
This is similar to iOS CryptoKit in Java but i am doing the other way around.
This is the android encryption code
public synchronized Map<String, String> encrypt(byte[] rawKey, byte[] rawData, #Nullable byte[] associatedData) throws StashDataEncryptionException {
byte[] rawEncryptionKey = null;
if (rawKey == null) {
SecureRandom secureRandom = new SecureRandom();
byte[] key = new byte[KEY_LENGTH_BYTE];
secureRandom.nextBytes(key);
rawEncryptionKey = key;
} else {
rawEncryptionKey = rawKey;
}
byte[] iv = null;
byte[] encrypted = null;
try {
iv = new byte[IV_LENGTH_BYTE];
secureRandom.nextBytes(iv);
final Cipher cipherEnc = getCipher();
cipherEnc.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(rawEncryptionKey, "AES"), new GCMParameterSpec(TAG_LENGTH_BIT, iv));
if (associatedData != null) {
cipherEnc.updateAAD(associatedData);
}
encrypted = cipherEnc.doFinal(rawData);
String base64Key = Base64.encodeToString(rawEncryptionKey, Base64.DEFAULT);
//concat all of it to a single message
ByteBuffer byteBuffer = ByteBuffer.allocate(1 + iv.length + encrypted.length);
byteBuffer.put((byte) iv.length);
byteBuffer.put(iv);
byteBuffer.put(encrypted);
byte[] cipherMessage = byteBuffer.array();
Map map = new HashMap<String, String>();
map.put(MAP_KEY, base64Key);
map.put(MAP_Byte_CONTENT, cipherMessage);
return map;
} catch (Exception e) {
throw new StashDataEncryptionException("could not encrypt data", e);
}
}
i checked the key,iv and tag lenght.Its same on the ios side as android

Hey there I played very long to day with this and I came up with a working Xcode playground demoing CryptoKit AES-GCM 256 encryption & decryption. I also had this error very often today but could solve it. You can clone my playgrounds repo and try it out, play with it:
https://github.com/Blackjacx/Playgrounds/blob/master/playgrounds/CryptoKit.playground/Contents.swift

Implementations will differ, enough to invalidate authenticated encryption.
Use an enterprise grade, cross platform compatible library like libsodium.

APK checksum- Binary Code Protection

How can i calculate the CheckSum of my APK file in android? I want to calculate the APK checksum and compare it everytime my app. executes to see if some one has modified the binary code? How can i calculate check sum and achieve this?

Updated in 2020 - Google Play can now optimise, repackage and re-sign uploaded .apks (and add security meta data to the .apk) so it's unlikely this tamper check is still valid. Better to use the SafetyNet attestation API to verify the device and in turn your app - just ensure you're verifying the signature offline on your server.
Here's some code to checksum your APK. I wrote and article on adding tamper detections to your apps (which ironically didn't include apk checksum).
private static long getApkFileChecksum(Context context) {
String apkPath = context.getPackageCodePath();
Long chksum = null;
try {
// Open the file and build a CRC32 checksum.
FileInputStream fis = new FileInputStream(new File(apkPath));
CRC32 chk = new CRC32();
CheckedInputStream cis = new CheckedInputStream(fis, chk);
byte[] buff = new byte[80];
while (cis.read(buff) >= 0) ;
chksum = chk.getValue();
} catch (Exception e) {
e.printStackTrace();
}
return chksum;
}
You could also use this to can the sha-256 of your apk...
public static String getApkFileDigest(Context context) {
String apkPath = context.getPackageCodePath();
try {
byte[] hashed= getDigest(new FileInputStream(apkPath), "SHA-256");
return Base64.encodeToString(hashed, Base64.DEFAULT);
} catch (Throwable throwable) {
throwable.printStackTrace();
}
return null;
}
public static final int BUFFER_SIZE = 2048;
public static byte[] getDigest(InputStream in, String algorithm) throws Throwable {
MessageDigest md = MessageDigest.getInstance(algorithm);
try {
DigestInputStream dis = new DigestInputStream(in, md);
byte[] buffer = new byte[BUFFER_SIZE];
while (dis.read(buffer) != -1) {
}
dis.close();
} finally {
in.close();
}
return md.digest();
}

Android ServerSocket programming with jCIFS streaming files

I've got a bit of an issue and I've been asking regarding it quite a few times, but I think I'm one step closer now, so hopefully someone can help me with the rest.
My previous questions:
Connect to NAS device from Android
How to open files in Android with default viewer using jCIFS
Put simply - I want to create an application that:
Can connect to a NAS device using jCIFS
Is capable of launching files in the default viewer - i.e. a video in the video player
The first part is relatively easy and I've already done that, but the second part is what's troubling me and what I've asked about a few times before. I think I've made some progress though.
I think I need to use a ServerSocket in my application to somehow create a bridge between the NAS and the application that's playing the content. I'm thinking this could be done using a Service. The files from the NAS device can be accessed as a FileInputStream.
There are plenty of applications on Market (i.e. ES File Explorer) that are capable of doing this without root access, so I know it's possible - at the moment I just don't know how.
I've been looking at Logcat while using some of the aforementioned applications, and they all seem to be creating a local server and then launch a video Intent from that server. How can this be achieved?

Basic answer is to use SmbFileInputStream to get InputStream You probably use this.
Now the tricky part is how to offer InputStream to other apps.
One possible approach, how many apps provide streaming of any InputStream to other apps on device, is to use http: URL scheme, and tunel your stream over http.
Then apps that can handle http URLs can open and use your data.
For this you have to make some kind of http server, which sounds difficult, but actually is achievable task. Good source to start with is nanohttpd library which is just one java source, originally used to list files in dirs, but you can adapt it to stream your InputStream over http. That's what I did with success.
Your url would look like http:// localhost:12345 where 12345 is port on which your server listens for requests. This port may be obtained from ServerSocket.getLocalPort(). Then give this URL to some app and your server waits for connection and sends data.
A note about http streaming: some apps (e.g. video players) like seekable http streams (http Range header). Since you can get also SmbRandomAccessFile, you can make your tiny server to provide any part of data in file. Android's built-in video player needs such seekable http stream in order to allow seeking in video file, otherwise it gives "Video can't be played" error. Your server must be ready to handle disconnects and multiple connects with different Range values.
Basic tasks of http server:
create ServerSocket
create Thread waiting for connection (Socket accept = serverSocket.accept()), one thread may be ok since you'd handle single client at a time
read http request (socket.getInputStream()), mainly check GET method and Range header)
send headers, mainly Content-Type, Content-Length, Accept-Ranges, Content-Range headers
send actual binary data, which is plain copying of InputStream (file) to OutputStream (socket)
handle disconnects, errors, exceptions
Good luck in implementation.
EDIT:
Here's my class that does the thing. It references some non-present classes for file, which should be trivial for you to replace by your file class.
/**
* This is simple HTTP local server for streaming InputStream to apps which are capable to read data from url.
* Random access input stream is optionally supported, depending if file can be opened in this mode.
*/
public class StreamOverHttp{
private static final boolean debug = false;
private final Browser.FileEntry file;
private final String fileMimeType;
private final ServerSocket serverSocket;
private Thread mainThread;
/**
* Some HTTP response status codes
*/
private static final String
HTTP_BADREQUEST = "400 Bad Request",
HTTP_416 = "416 Range not satisfiable",
HTTP_INTERNALERROR = "500 Internal Server Error";
public StreamOverHttp(Browser.FileEntry f, String forceMimeType) throws IOException{
file = f;
fileMimeType = forceMimeType!=null ? forceMimeType : file.mimeType;
serverSocket = new ServerSocket(0);
mainThread = new Thread(new Runnable(){
#Override
public void run(){
try{
while(true) {
Socket accept = serverSocket.accept();
new HttpSession(accept);
}
}catch(IOException e){
e.printStackTrace();
}
}
});
mainThread.setName("Stream over HTTP");
mainThread.setDaemon(true);
mainThread.start();
}
private class HttpSession implements Runnable{
private boolean canSeek;
private InputStream is;
private final Socket socket;
HttpSession(Socket s){
socket = s;
BrowserUtils.LOGRUN("Stream over localhost: serving request on "+s.getInetAddress());
Thread t = new Thread(this, "Http response");
t.setDaemon(true);
t.start();
}
#Override
public void run(){
try{
openInputStream();
handleResponse(socket);
}catch(IOException e){
e.printStackTrace();
}finally {
if(is!=null) {
try{
is.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
}
private void openInputStream() throws IOException{
// openRandomAccessInputStream must return RandomAccessInputStream if file is ssekable, null otherwise
is = openRandomAccessInputStream(file);
if(is!=null)
canSeek = true;
else
is = openInputStream(file, 0);
}
private void handleResponse(Socket socket){
try{
InputStream inS = socket.getInputStream();
if(inS == null)
return;
byte[] buf = new byte[8192];
int rlen = inS.read(buf, 0, buf.length);
if(rlen <= 0)
return;
// Create a BufferedReader for parsing the header.
ByteArrayInputStream hbis = new ByteArrayInputStream(buf, 0, rlen);
BufferedReader hin = new BufferedReader(new InputStreamReader(hbis));
Properties pre = new Properties();
// Decode the header into params and header java properties
if(!decodeHeader(socket, hin, pre))
return;
String range = pre.getProperty("range");
Properties headers = new Properties();
if(file.fileSize!=-1)
headers.put("Content-Length", String.valueOf(file.fileSize));
headers.put("Accept-Ranges", canSeek ? "bytes" : "none");
int sendCount;
String status;
if(range==null || !canSeek) {
status = "200 OK";
sendCount = (int)file.fileSize;
}else {
if(!range.startsWith("bytes=")){
sendError(socket, HTTP_416, null);
return;
}
if(debug)
BrowserUtils.LOGRUN(range);
range = range.substring(6);
long startFrom = 0, endAt = -1;
int minus = range.indexOf('-');
if(minus > 0){
try{
String startR = range.substring(0, minus);
startFrom = Long.parseLong(startR);
String endR = range.substring(minus + 1);
endAt = Long.parseLong(endR);
}catch(NumberFormatException nfe){
}
}
if(startFrom >= file.fileSize){
sendError(socket, HTTP_416, null);
inS.close();
return;
}
if(endAt < 0)
endAt = file.fileSize - 1;
sendCount = (int)(endAt - startFrom + 1);
if(sendCount < 0)
sendCount = 0;
status = "206 Partial Content";
((RandomAccessInputStream)is).seek(startFrom);
headers.put("Content-Length", "" + sendCount);
String rangeSpec = "bytes " + startFrom + "-" + endAt + "/" + file.fileSize;
headers.put("Content-Range", rangeSpec);
}
sendResponse(socket, status, fileMimeType, headers, is, sendCount, buf, null);
inS.close();
if(debug)
BrowserUtils.LOGRUN("Http stream finished");
}catch(IOException ioe){
if(debug)
ioe.printStackTrace();
try{
sendError(socket, HTTP_INTERNALERROR, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage());
}catch(Throwable t){
}
}catch(InterruptedException ie){
// thrown by sendError, ignore and exit the thread
if(debug)
ie.printStackTrace();
}
}
private boolean decodeHeader(Socket socket, BufferedReader in, Properties pre) throws InterruptedException{
try{
// Read the request line
String inLine = in.readLine();
if(inLine == null)
return false;
StringTokenizer st = new StringTokenizer(inLine);
if(!st.hasMoreTokens())
sendError(socket, HTTP_BADREQUEST, "Syntax error");
String method = st.nextToken();
if(!method.equals("GET"))
return false;
if(!st.hasMoreTokens())
sendError(socket, HTTP_BADREQUEST, "Missing URI");
while(true) {
String line = in.readLine();
if(line==null)
break;
// if(debug && line.length()>0) BrowserUtils.LOGRUN(line);
int p = line.indexOf(':');
if(p<0)
continue;
final String atr = line.substring(0, p).trim().toLowerCase();
final String val = line.substring(p + 1).trim();
pre.put(atr, val);
}
}catch(IOException ioe){
sendError(socket, HTTP_INTERNALERROR, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage());
}
return true;
}
}
/**
* #param fileName is display name appended to Uri, not really used (may be null), but client may display it as file name.
* #return Uri where this stream listens and servers.
*/
public Uri getUri(String fileName){
int port = serverSocket.getLocalPort();
String url = "http://localhost:"+port;
if(fileName!=null)
url += '/'+URLEncoder.encode(fileName);
return Uri.parse(url);
}
public void close(){
BrowserUtils.LOGRUN("Closing stream over http");
try{
serverSocket.close();
mainThread.join();
}catch(Exception e){
e.printStackTrace();
}
}
/**
* Returns an error message as a HTTP response and
* throws InterruptedException to stop further request processing.
*/
private static void sendError(Socket socket, String status, String msg) throws InterruptedException{
sendResponse(socket, status, "text/plain", null, null, 0, null, msg);
throw new InterruptedException();
}
private static void copyStream(InputStream in, OutputStream out, byte[] tmpBuf, long maxSize) throws IOException{
while(maxSize>0){
int count = (int)Math.min(maxSize, tmpBuf.length);
count = in.read(tmpBuf, 0, count);
if(count<0)
break;
out.write(tmpBuf, 0, count);
maxSize -= count;
}
}
/**
* Sends given response to the socket, and closes the socket.
*/
private static void sendResponse(Socket socket, String status, String mimeType, Properties header, InputStream isInput, int sendCount, byte[] buf, String errMsg){
try{
OutputStream out = socket.getOutputStream();
PrintWriter pw = new PrintWriter(out);
{
String retLine = "HTTP/1.0 " + status + " \r\n";
pw.print(retLine);
}
if(mimeType!=null) {
String mT = "Content-Type: " + mimeType + "\r\n";
pw.print(mT);
}
if(header != null){
Enumeration<?> e = header.keys();
while(e.hasMoreElements()){
String key = (String)e.nextElement();
String value = header.getProperty(key);
String l = key + ": " + value + "\r\n";
// if(debug) BrowserUtils.LOGRUN(l);
pw.print(l);
}
}
pw.print("\r\n");
pw.flush();
if(isInput!=null)
copyStream(isInput, out, buf, sendCount);
else if(errMsg!=null) {
pw.print(errMsg);
pw.flush();
}
out.flush();
out.close();
}catch(IOException e){
if(debug)
BrowserUtils.LOGRUN(e.getMessage());
}finally {
try{
socket.close();
}catch(Throwable t){
}
}
}
}
/**
* Seekable InputStream.
* Abstract, you must add implementation for your purpose.
*/
abstract class RandomAccessInputStream extends InputStream{
/**
* #return total length of stream (file)
*/
abstract long length();
/**
* Seek within stream for next read-ing.
*/
abstract void seek(long offset) throws IOException;
#Override
public int read() throws IOException{
byte[] b = new byte[1];
read(b);
return b[0]&0xff;
}
}

In Samsung S5 (Android version 5.1.1), I faced a problem of range request starting from a value greater than the file size and I solved it by setting status = "200 OK" as below:
if (startFrom >= contentLength) {
// when you receive a request from MediaPlayer that does not contain Range in the HTTP header , then it is requesting a new stream
// https://code.google.com/p/android/issues/detail?id=3031
status = "200 OK";
}
The remaining headers were left as a fresh request for the stream

Need help debugging my code

I need some input about my code.
Basically, I have a method to load music from Class A
public void onListItemClick(ListView parent, View v, int position, long id){
musicIndex = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
cursor.moveToPosition(position);
filePath = cursor.getString(musicIndex);
fileName = new File(filePath).getName();
playMusic();//Play the selected music
}
public void playMusic(){
if(mPlayer.isPlaying()){
mPlayer.reset();
}
try{
mPlayer.setDataSource(filePath);
mPlayer.prepare();
mPlayer.start();
BeatDetection beatDetect = new BeatDetection();
beatDetect.init();
}catch (Exception e){
}
}
That method will call the init() method in Class B
public void init() throws Exception{
energy = 0;
variance = 0;
constant = 0;
isBeat = false;
sensitivity = 0;
dBuffer = new float[sampleRate / bufferSize];
eBuffer = new float[sampleRate / bufferSize];
timer = System.currentTimeMillis();
MusicLoad msc = new MusicLoad();
totalMs = 0;
seeking = true;
//msc.printText();
decode(msc.fileName, 25, 40);
}
In that method, it initializes everything and call the decode() method
public void decode(String path, int startMs, int maxMs)
throws IOException, javazoom.jl.decoder.DecoderException {
debug();
File in = new File(path);
InputStream inStream = new BufferedInputStream(new FileInputStream(in), 8 * 1024);
ByteArrayOutputStream outStream = new ByteArrayOutputStream(1024);
try {
Bitstream bitstream = new Bitstream(inStream);
Decoder decoder = new Decoder();
boolean done = false;
while (! done) {
Header frameHeader = bitstream.readFrame();
if (frameHeader == null) {
done = true;
} else {
totalMs += frameHeader.ms_per_frame();
if (totalMs >= startMs) {
seeking = false;
}
if (! seeking) {
SampleBuffer output = (SampleBuffer) decoder.decodeFrame(frameHeader, bitstream);
if (output.getSampleFrequency() != 44100 || output.getChannelCount() != 2) {
throw new javazoom.jl.decoder.DecoderException("mono or non-44100 MP3 not supported", null);
}
short[] pcm = output.getBuffer();
for (short s : pcm) {
outStream.write(s & 0xff);
outStream.write((s >> 8 ) & 0xff);
}
}
if (totalMs >= (startMs + maxMs)) {
done = true;
}
}
bitstream.closeFrame();
}
byte[] abAudioData = outStream.toByteArray();
calculation(abAudioData);
} catch (BitstreamException e) {
throw new IOException("Bitstream error: " + e);
} catch (DecoderException e) {
Log.w("Decoder error", e);
throw new javazoom.jl.decoder.DecoderException("Error",e);
} finally {
inStream.close();
}
}
Don't mind reading all the code lines. If you guys notice I put debug() in the beginning to see whether the method is called or not. At this point, the debug() is properly called. However, if I put the debug() after the line File in = new File(path);, the debug() will not be called anymore. It seems like the code is stop running at that point.
The ultimate result is, I can load and play the song without any problem. However, the decode() is not called and there is no error whatsoever. I'm stuck at pointing out the problem at this point. So if there's any input please help me.
EDIT: After I tried tracing the "path" variable, it returns NULL so the error is NullPointerException. Seems like the "fileName" variable from Class A is not passed to Class B. Any suggestion?

If you are using Eclipse with ADT then it's very easy to debug your Android apps, just add a breakpoint (probably in the new File(...) line) and see what happens.
My guess here is that File in = new File(path); probably is throwing a IOException in your decode method, that exception is bubbling first to init() and then to playMusic(), where it is caught by try catch block. Your catch is empty so you are not seeing anything. Try debugging as I said or add some logging info in the catch block.

This is just something to look at, but from the doc page
http://developer.android.com/reference/java/io/File.html#File%28java.lang.String%29
"The actual file referenced by a File may or may not exist. It may also, despite the name File, be a directory or other non-regular file."
If you had the path wrong, it may be trying to create the file and you may not have the correct permission to do so. Perhaps: WRITE_EXTERNAL_STORAGE.

I know this post is old, but I just wanted to show how to get the file path to read/write files for others that come across this post as I have:
String filePath = myContext.getFilesDir().getPath().toString() + "/sysout.log";
File file = new File(filePath);
These two lines will create (open if it exists, and overwrite) a file named "sysout.log" in the folder /data/data/com.app.name/files/; myContext is just the current context. Using this technique alleviates problems with defining your own path name. Hope this helps someone.

Android Mediaplayer: setDataSource issue for downloaded media file

I have an application that will record and play audio files. Some of the audio files are downloaded using simple standard http downloads using httpclient. It worked like a charm for a long time. Now all of a sudden I cannot play the files I download. It fails with this stack. I store the files on the SDCard and I experience the problem both on a handset and a USB connected device.
I have checked that the downloaded file is cool on the server, and I can play it without any issues.
These are the code snippets I use ( I know that recordingFile is a valid path for the file).
// inside the activity class
private void playRecording() throws IOException{
File recordingFile = new File(recordingFileName);
FileInputStream recordingInputStream = new FileInputStream(recordingFile);
audioMediaPlayer.playAudio(recordingInputStream);
}
Here is the media player code:
// inside my media player class which handles the recordings
public void playAudio(FileInputStream audioInputStream) throws IOException {
mediaPlayer.reset();
mediaPlayer.setDataSource(audioInputStream.getFD());
mediaPlayer.prepare();
mediaPlayer.start();
}
Here is the exception:
E/MediaPlayerService( 555): offset error
E/MediaPlayer( 786): Unable to to create media player
W/System.err( 786): java.io.IOException: setDataSourceFD failed.: status=0x80000000
W/System.err( 786): at android.media.MediaPlayer.setDataSource(Native Method)
W/System.err( 786): at android.media.MediaPlayer.setDataSource(MediaPlayer.java:632)
W/System.err( 786): at net.xxx.xxx.AudioMediaPlayer.playAudio(AudioMediaPlayer.java:69)
W/System.err( 786): at net.xxx.xxx.Downloads.playRecording(Downloads.java:299)
W/System.err( 786): at net.xxx.xxx.Downloads.access$0(Downloads.java:294)
W/System.err( 786): at net.xxx.xxx.Downloads$1.onClick(Downloads.java:135)
I have tried seeking some answer of the offset error, but not really clear what this issue might be.
PS I download the file with this code:
public FileOutputStream executeHttpGet(FileOutputStream fileOutputStream) throws ClientProtocolException, IOException{
try {
// Execute HTTP Post Request
httpResponse = httpClient.execute(httpPost, localContext);
int status = httpResponse.getStatusLine().getStatusCode();
// we assume that the response body contains the error message
if (status != HttpStatus.SC_OK) {
ByteArrayOutputStream ostream = new ByteArrayOutputStream();
httpResponse.getEntity().writeTo(ostream);
fileOutputStream = null;
} else {
InputStream content = httpResponse.getEntity().getContent();
byte[] buffer = new byte[1024];
int len = 0;
while ( (len = content.read(buffer)) > 0 ) {
fileOutputStream.write(buffer,0, len);
}
fileOutputStream.close();
content.close(); // this will also close the connection
}
} catch (ClientProtocolException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
fileOutputStream = null;
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
fileOutputStream = null;
}
return fileOutputStream;
}

I solved it on my own. As I put it my comment above the solution was this:
When I refactored part of the code I made a typo on a hash code I use to allow downloads and not. Unfortunately I didn't have the proper catch when I downloaded the file forcing the file to be empty. Basically I send a bad request header if you try to retrieve a file without a proper activation code.
The culprit was here:
if (status != HttpStatus.SC_OK) {
ByteArrayOutputStream ostream = new ByteArrayOutputStream();
httpResponse.getEntity().writeTo(ostream);
fileOutputStream = null;
} else {
InputStream content = httpResponse.getEntity().getContent();
byte[] buffer = new byte[1024];
int len = 0;
while ( (len = content.read(buffer)) > 0 ) {
fileOutputStream.write(buffer,0, len);
}
fileOutputStream.close();
content.close(); // this will also close the connection
}
For cases where the status code came back a as bad (i.e. bad request header for blocked accesses). What I missed was to capture the case of a null pointer there and that caused a SQLite entry to be updated claiming to the app that the download was successful but yet it wasn't.
Lesson learnt: Always put in the null checks for these cases even for prototypes. :-)

First, make sure your device is not mounted. Either Android or the host PC can access the SD card, but not both simultaneously.
Second, it is unclear why you are using a FileInputStream and getFD(). Just pass the path to the file on the SD card to the MediaPlayer (e.g., new File(Environment.getExternalStorageDirectory(), "yourfile.mp3")) and let the player open the file.