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feat: Improve code quality of the cryptography

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This commit is contained in:
PapaTutuWawa 2023-07-21 17:30:59 +02:00
parent eab467ee1d
commit 563b0386d6
6 changed files with 212 additions and 239 deletions
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90
example/lib/main.dart
View File

@ -12,50 +12,22 @@ void main() {
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
title: 'Moxplatform Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
home: const MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
class MyHomePage extends StatelessWidget {
const MyHomePage({super.key});
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
Future<void> _incrementCounter() async {
Future<void> _cryptoTest() async {
final result = await FilePicker.platform.pickFiles();
if (result == null) {
return;
@ -65,7 +37,7 @@ class _MyHomePageState extends State<MyHomePage> {
final path = result.files.single.path;
final enc = await MoxplatformPlugin.crypto.encryptFile(
path!,
path + '.enc',
'$path.enc',
Uint8List.fromList(List.filled(32, 1)),
Uint8List.fromList(List.filled(16, 2)),
CipherAlgorithm.aes256CbcPkcs7,
@ -76,13 +48,13 @@ class _MyHomePageState extends State<MyHomePage> {
final diff = end.millisecondsSinceEpoch - start.millisecondsSinceEpoch;
print('TIME: ${diff / 1000}s');
print('DONE (${enc != null})');
final lengthEnc = await File(path + ".enc").length();
final lengthEnc = await File('$path.enc').length();
final lengthOrig = await File(path).length();
print('Encrypted file is $lengthEnc Bytes large (Orig $lengthOrig)');
await MoxplatformPlugin.crypto.decryptFile(
path + '.enc',
path + '.dec',
'$path.enc',
'$path.dec',
Uint8List.fromList(List.filled(32, 1)),
Uint8List.fromList(List.filled(16, 2)),
CipherAlgorithm.aes256CbcPkcs7,
@ -90,69 +62,41 @@ class _MyHomePageState extends State<MyHomePage> {
);
print('DONE');
final lengthDec = await File(path + ".dec").length();
final lengthDec = await File('$path.dec').length();
print('Decrypted file is $lengthDec Bytes large (Orig $lengthOrig)');
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
title: const Text('Moxplatform Demo'),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
ElevatedButton(
onPressed: _cryptoTest,
child: const Text('Test cryptography'),
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
ElevatedButton(
onPressed: () {
MoxplatformPlugin.contacts.recordSentMessage('Hallo', 'Welt');
},
child: Text('Test recordSentMessage (no fallback)'),
child: const Text('Test recordSentMessage (no fallback)'),
),
ElevatedButton(
onPressed: () {
MoxplatformPlugin.contacts.recordSentMessage('Person', 'Person', fallbackIcon: FallbackIconType.person);
},
child: Text('Test recordSentMessage (person fallback)'),
child: const Text('Test recordSentMessage (person fallback)'),
),
ElevatedButton(
onPressed: () {
MoxplatformPlugin.contacts.recordSentMessage('Notes', 'Notes', fallbackIcon: FallbackIconType.notes);
},
child: Text('Test recordSentMessage (notes fallback)'),
child: const Text('Test recordSentMessage (notes fallback)'),
),
],
),

26
packages/moxplatform_android/android/src/main/java/me/polynom/moxplatform_android/Constants.kt Normal file
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@ -0,0 +1,26 @@
package me.polynom.moxplatform_android
// The tag we use for logging.
const val TAG = "Moxplatform"
// The size of the buffer to hashing, encryption, and decryption in bytes.
const val BUFFER_SIZE = 8096
// TODO: Maybe try again to rewrite the entire plugin in Kotlin
//const val METHOD_CHANNEL_KEY = "me.polynom.moxplatform_android"
//const val BACKGROUND_METHOD_CHANNEL_KEY = METHOD_CHANNEL_KEY + "_bg"
// https://github.com/ekasetiawans/flutter_background_service/blob/e427f3b70138ec26f9671c2617f9061f25eade6f/packages/flutter_background_service_android/android/src/main/java/id/flutter/flutter_background_service/BootReceiver.java#L20
//const val WAKELOCK_DURATION = 10*60*1000L;
// The name of the wakelock the background service manager holds.
//const val SERVICE_WAKELOCK_NAME = "BackgroundService.Lock"
//const val DATA_RECEIVER_METHOD_NAME = "dataReceived"
// Shared preferences keys
//const val SHARED_PREFERENCES_KEY = "me.polynom.moxplatform_android"
//const val SP_MANUALLY_STOPPED_KEY = "manually_stopped"
//const val SP_ENTRYPOINT_KEY = "entrypoint_handle"
//const val SP_EXTRA_DATA_KEY = "extra_data"
//const val SP_AUTO_START_AT_BOOT_KEY = "auto_start_at_boot"

144
packages/moxplatform_android/android/src/main/java/me/polynom/moxplatform_android/Crypto.kt Normal file
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@ -0,0 +1,144 @@
package me.polynom.moxplatform_android
import android.util.Log
import java.io.FileInputStream
import java.io.FileOutputStream
import java.lang.Exception
import java.security.MessageDigest
import javax.crypto.Cipher
import javax.crypto.CipherOutputStream
import javax.crypto.spec.IvParameterSpec
import javax.crypto.spec.SecretKeySpec
// A FileOutputStream that continuously hashes whatever it writes to the file.
private class HashedFileOutputStream(name: String, hashAlgorithm: String) : FileOutputStream(name) {
private val digest: MessageDigest
init {
this.digest = MessageDigest.getInstance(hashAlgorithm)
}
override fun write(buffer: ByteArray, offset: Int, length: Int) {
super.write(buffer, offset, length)
digest.update(buffer, offset, length)
}
fun digest() : ByteArray {
return digest.digest()
}
}
fun getCipherSpecFromInteger(algorithmType: Int): String {
return when (algorithmType) {
0 -> "AES_128/GCM/NoPadding"
1 -> "AES_256/GCM/NoPadding"
2 -> "AES_256/CBC/PKCS7PADDING"
else -> ""
}
}
// Compute the hash, specified by @algorithm, of the file at path @srcFile. If an exception
// occurs, returns null. If everything went well, returns the raw hash of @srcFile.
fun hashFile(srcFile: String, algorithm: String): ByteArray? {
val buffer = ByteArray(BUFFER_SIZE)
try {
val digest = MessageDigest.getInstance(algorithm)
val fInputStream = FileInputStream(srcFile)
var length: Int
while (true) {
length = fInputStream.read()
if (length <= 0) break
// Only update the digest if we read more than 0 bytes
digest.update(buffer, 0, length)
}
fInputStream.close()
return digest.digest()
} catch (e: Exception) {
Log.e(TAG, "[hashFile]: " + e.stackTraceToString())
return null
}
}
// Encrypt the plaintext file at @src to @dest using the secret key @key and the IV @iv. The algorithm is chosen using @cipherAlgorithm. The file is additionally
// hashed before and after encryption using the hash algorithm specified by @hashAlgorithm.
fun encryptAndHash(src: String, dest: String, key: ByteArray, iv: ByteArray, cipherAlgorithm: String, hashAlgorithm: String): HashMap<String, ByteArray>? {
val buffer = ByteArray(BUFFER_SIZE)
val secretKey = SecretKeySpec(key, cipherAlgorithm)
try {
val digest = MessageDigest.getInstance(hashAlgorithm)
val cipher = Cipher.getInstance(cipherAlgorithm)
cipher.init(Cipher.ENCRYPT_MODE, secretKey, IvParameterSpec(iv))
val fileInputStream = FileInputStream(src)
val fileOutputStream = HashedFileOutputStream(dest, hashAlgorithm)
val cipherOutputStream = CipherOutputStream(fileOutputStream, cipher)
var length: Int
while (true) {
length = fileInputStream.read(buffer)
if (length <= 0) break
digest.update(buffer, 0, length)
cipherOutputStream.write(buffer, 0, length)
}
// Flush and close
cipherOutputStream.flush()
cipherOutputStream.close()
fileInputStream.close()
return hashMapOf(
"plaintextHash" to digest.digest(),
"ciphertextHash" to fileOutputStream.digest(),
)
} catch (e: Exception) {
Log.e(TAG, "[encryptAndHash]: " + e.stackTraceToString())
return null
}
}
// Decrypt the ciphertext file at @src to @dest using the secret key @key and the IV @iv. The algorithm is chosen using @cipherAlgorithm. The file is additionally
// hashed before and after decryption using the hash algorithm specified by @hashAlgorithm.
fun decryptAndHash(src: String, dest: String, key: ByteArray, iv: ByteArray, cipherAlgorithm: String, hashAlgorithm: String): HashMap<String, ByteArray>? {
// Shamelessly stolen from https://github.com/hugo-pcl/native-crypto-flutter/pull/3
val buffer = ByteArray(BUFFER_SIZE)
val secretKey = SecretKeySpec(key, cipherAlgorithm)
try {
val digest = MessageDigest.getInstance(hashAlgorithm)
val cipher = Cipher.getInstance(cipherAlgorithm)
cipher.init(Cipher.ENCRYPT_MODE, secretKey, IvParameterSpec(iv))
val fileInputStream = FileInputStream(src)
val fileOutputStream = HashedFileOutputStream(dest, hashAlgorithm)
val cipherOutputStream = CipherOutputStream(fileOutputStream, cipher)
// Read, decrypt, and hash until we read 0 bytes
var length: Int
while (true) {
length = fileInputStream.read(buffer)
if (length <= 0) break
digest.update(buffer, 0, length)
cipherOutputStream.write(buffer, 0, length)
}
// Flush
cipherOutputStream.flush()
cipherOutputStream.close()
fileInputStream.close()
return hashMapOf(
"plaintextHash" to digest.digest(),
"ciphertextHash" to fileOutputStream.digest(),
)
} catch (e: Exception) {
Log.e(TAG, "[hashAndDecrypt]: " + e.stackTraceToString())
return null
}
}

34
packages/moxplatform_android/android/src/main/java/me/polynom/moxplatform_android/HashedFileOutputStream.java
View File

@ -1,34 +0,0 @@
package me.polynom.moxplatform_android;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class HashedFileOutputStream extends FileOutputStream {
public MessageDigest digest;
public HashedFileOutputStream(String name, String hashSpec) throws FileNotFoundException, NoSuchAlgorithmException {
super(name);
digest = MessageDigest.getInstance(hashSpec);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
super.write(b, off, len);
digest.update(b, off, len);
}
public String getHexHash() {
StringBuffer result = new StringBuffer();
for (byte b : digest.digest()) result.append(Integer.toString((b & 0xff) + 0x100, 16).substring(1));
return result.toString();
}
public byte[] getHash() {
return digest.digest();
}
}

149
packages/moxplatform_android/android/src/main/java/me/polynom/moxplatform_android/MoxplatformAndroidPlugin.java
View File

@ -1,6 +1,7 @@
package me.polynom.moxplatform_android;
import static me.polynom.moxplatform_android.RecordSentMessageKt.recordSentMessage;
import static me.polynom.moxplatform_android.CryptoKt.*;
import android.app.ActivityManager;
import android.content.BroadcastReceiver;
@ -8,28 +9,17 @@ import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Icon;
import android.os.Build;
import android.util.Log;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.core.app.Person;
import androidx.core.content.ContextCompat;
import androidx.core.content.pm.ShortcutInfoCompat;
import androidx.core.content.pm.ShortcutManagerCompat;
import androidx.core.graphics.drawable.IconCompat;
import androidx.localbroadcastmanager.content.LocalBroadcastManager;
import java.io.FileInputStream;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
@ -169,7 +159,16 @@ public class MoxplatformAndroidPlugin extends BroadcastReceiver implements Flutt
int algorithm = (int) args.get(4);
String hashSpec = (String) args.get(5);
result.success(encryptFile(src, dest, key, iv, algorithm, hashSpec));
result.success(
encryptAndHash(
src,
dest,
key,
iv,
getCipherSpecFromInteger(algorithm),
hashSpec
)
);
}
});
encryptionThread.start();
@ -186,7 +185,16 @@ public class MoxplatformAndroidPlugin extends BroadcastReceiver implements Flutt
int algorithm = (int) args.get(4);
String hashSpec = (String) args.get(5);
result.success(decryptFile(src, dest, key, iv, algorithm, hashSpec));
result.success(
decryptAndHash(
src,
dest,
key,
iv,
getCipherSpecFromInteger(algorithm),
hashSpec
)
);
}
});
decryptionThread.start();
@ -254,119 +262,4 @@ public class MoxplatformAndroidPlugin extends BroadcastReceiver implements Flutt
Log.d(TAG, "Detached from service");
this.service = null;
}
private String getCipherSpecFromInteger(int algorithm) {
switch (algorithm) {
case 0: return "AES_128/GCM/NoPadding";
case 1: return "AES_256/GCM/NoPadding";
case 2: return "AES_256/CBC/PKCS7PADDING";
default:
Log.d(TAG, "INVALID ALGORITHM");
return "";
}
}
public HashMap<String, byte[]> encryptFile(String src, String dest, byte[] key, byte[] iv, int algorithm, String hashSpec) {
String spec = getCipherSpecFromInteger(algorithm);
if (spec.isEmpty()) {
return null;
}
// Shamelessly stolen from https://github.com/hugo-pcl/native-crypto-flutter/pull/3
byte[] buffer = new byte[8096];
SecretKeySpec sk = new SecretKeySpec(key, spec);
try {
MessageDigest md = MessageDigest.getInstance(hashSpec);
Cipher cipher = Cipher.getInstance(spec);
cipher.init(Cipher.ENCRYPT_MODE, sk, new IvParameterSpec(iv));
FileInputStream fin = new FileInputStream(src);
HashedFileOutputStream fout = new HashedFileOutputStream(dest, hashSpec);
CipherOutputStream cout = new CipherOutputStream(fout, cipher);
int len = 0;
int bufLen = 0;
while (true) {
len = fin.read(buffer);
if (len != 0 && len > 0) {
md.update(buffer, 0, len);
cout.write(buffer, 0, len);
} else {
break;
}
}
cout.flush();
cout.close();
fin.close();
return new HashMap<String, byte[]>() {{
put("plaintext_hash", md.digest());
put("ciphertext_hash", fout.getHash());
}};
} catch (Exception ex) {
Log.d(TAG, "ENC: " + ex.getMessage());
return null;
}
}
public HashMap<String, byte[]> decryptFile(String src, String dest, byte[] key, byte[] iv, int algorithm, String hashSpec) {
String spec = getCipherSpecFromInteger(algorithm);
if (spec.isEmpty()) {
return null;
}
// Shamelessly stolen from https://github.com/hugo-pcl/native-crypto-flutter/pull/3
byte[] buffer = new byte[8096];
SecretKeySpec sk = new SecretKeySpec(key, spec);
try {
Cipher cipher = Cipher.getInstance(spec);
cipher.init(Cipher.DECRYPT_MODE, sk, new IvParameterSpec(iv));
FileInputStream fin = new FileInputStream(src);
HashedFileOutputStream fout = new HashedFileOutputStream(dest, hashSpec);
CipherOutputStream cout = new CipherOutputStream(fout, cipher);
MessageDigest md = MessageDigest.getInstance(hashSpec);
Log.d(TAG, "Reading from " + src + ", writing to " + dest);
int len = 0;
while (true) {
len = fin.read(buffer);
if (len != 0 && len > 0) {
cout.write(buffer, 0, len);
md.update(buffer, 0, len);
} else {
break;
}
}
cout.flush();
cout.close();
fin.close();
return new HashMap<String, byte[]>() {{
put("plaintext_hash", md.digest());
put("ciphertext_hash", fout.getHash());
}};
} catch (Exception ex) {
Log.d(TAG, "DEC: " + ex.getMessage());
return null;
}
}
public byte[] hashFile(String src, String algorithm) {
byte[] buffer = new byte[8096];
try {
MessageDigest md = MessageDigest.getInstance(algorithm);
FileInputStream fin = new FileInputStream(src);
int len = 0;
while (true) {
len = fin.read(buffer);
if (len != 0 && len > 0) {
md.update(buffer, 0, len);
} else {
break;
}
}
return md.digest();
} catch (Exception ex) {
Log.d(TAG, "Hash: " + ex.getMessage());
return null;
}
}
}

8
packages/moxplatform_android/lib/src/crypto_android.dart
View File

@ -28,8 +28,8 @@ class AndroidCryptographyImplementation extends CryptographyImplementation {
// ignore: argument_type_not_assignable
final result = Map<String, dynamic>.from(resultRaw);
return CryptographyResult(
result['plaintext_hash']! as Uint8List,
result['ciphertext_hash']! as Uint8List,
result['plaintextHash']! as Uint8List,
result['ciphertextHash']! as Uint8List,
);
}
@ -56,8 +56,8 @@ class AndroidCryptographyImplementation extends CryptographyImplementation {
// ignore: argument_type_not_assignable
final result = Map<String, dynamic>.from(resultRaw);
return CryptographyResult(
result['plaintext_hash']! as Uint8List,
result['ciphertext_hash']! as Uint8List,
result['plaintextHash']! as Uint8List,
result['ciphertextHash']! as Uint8List,
);
}