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你好，我一直在探索新的工具，爲我們提供了Visual Studio 2015是Xamarin，我已經在Android上實現了一個應用程序，但我目前正在將它翻譯成C＃應用程序是平臺，我不知道如何執行加密，我發現下面的例子將堅持，但只有加密和解密，也包括已經在Java中實現的代碼，我希望有人可以支持我，因爲我得到很多錯誤。Xamarin在C＃代碼中的加密和解密基於Android
loggedUser = null;
sharedPreferences = getSharedPreferences(AppConstants.PREFERENCES_FILE_NAME, MODE_PRIVATE);
if (sharedPreferences.getAll().isEmpty()) {
Intent loginActivityIntent = new Intent(MainActivity.this, LoginActivity.class);
startActivity(loginActivityIntent);
finishAffinity();
}
String loggedUserUsername = sharedPreferences.getString(AppConstants.LOGIN_CREDENTIAL_USERNAME_KEY, "");
if (loggedUserUsername.isEmpty()) {
Intent loginActivityIntent = new Intent(MainActivity.this, LoginActivity.class);
loginActivityIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(loginActivityIntent);
finishAffinity();
} else {
File filesDirectory = new File(getFilesDir().getPath());
for (File file: filesDirectory.listFiles()) {
if (file.getName().contains(loggedUserUsername) && file.getName().contains(AppConstants.USER_INFO_FILE_SUFFIX)) {
String deviceId;
String deviceKey;
byte[] secretBytes;
byte[] ivBytes;
FileInputStream fileInputStream = null;
CipherInputStream cipherInputStream = null;
ObjectInputStream objectInputStream = null;
try {
deviceId = sharedPreferences.getString(AppConstants.LOGIN_CREDENTIAL_DEVICE_ID_KEY, "").replace("-", "");
deviceKey = sharedPreferences.getString(AppConstants.LOGIN_CREDENTIAL_DEVICE_KEY_KEY, "").replace("-", "");
secretBytes = deviceKey.substring(0, 16).getBytes();
ivBytes = deviceId.substring(deviceId.length() - 16, deviceId.length()).getBytes();
fileInputStream = openFileInput(file.getName());
final SecretKey secretKey = new SecretKeySpec(secretBytes, "AES");
final IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes);
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);
cipherInputStream = new CipherInputStream(fileInputStream, cipher);
objectInputStream = new ObjectInputStream(cipherInputStream);
loggedUser = new User((String)objectInputStream.readObject());
} catch (ClassNotFoundException | NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | InvalidAlgorithmParameterException | IOException | JSONException e) {
if (AppConstants.DEBUG) Log.e(TAG, AppConstants.EXCEPTION_CAUGHT_MESSAGE + e.getMessage(), e);
loggedUser = null;
} finally {
if (objectInputStream != null) {
try {
objectInputStream.close();
} catch (IOException e) {
if (AppConstants.DEBUG) Log.e(TAG, AppConstants.EXCEPTION_CAUGHT_MESSAGE + e.getMessage(), e);
}
} else {
if (AppConstants.DEBUG) Log.e(TAG, "objectOutputStream:null");
}
if (cipherInputStream != null) {
try {
cipherInputStream.close();
} catch (IOException e) {
if (AppConstants.DEBUG) Log.e(TAG, AppConstants.EXCEPTION_CAUGHT_MESSAGE + e.getMessage(), e);
}
} else {
if (AppConstants.DEBUG) Log.e(TAG, "cipherOutputStream:null");
}
if (fileInputStream != null) {
try {
fileInputStream.close();
} catch (IOException e) {
if (AppConstants.DEBUG) Log.e(TAG, AppConstants.EXCEPTION_CAUGHT_MESSAGE + e.getMessage(), e);
}
} else {
if (AppConstants.DEBUG) Log.e(TAG, "fileOutputStream:null");
}
}
break;
}
}
}
下面的代碼C＃
base.OnCreate(savedInstanceState);
loggedUser = null;
sharedPreferences = GetSharedPreferences(AppConstants.PREFERENCES_FILE_NAME, MODE_PRIVATE);
if (sharedPreferences.All.Count == 0)
{
Intent loginActivityIntent = new Intent(MainActivity.this, LoginActivity.Class);
loginActivityIntent.SetFlags(ActivityFlags.ClearTop);
StartActivity(loginActivityIntent);
FinishAffinity();
}
else
{
Java.IO.File filesDirectory = new Java.IO.File(FilesDir.Path);
foreach (Java.IO.File file in filesDirectory.ListFiles())
{
if (file.Name.Contains(loggedUser) && file.Name.Contains(AppConstants.USER_INFO_FILE_SUFFIX))
{
string deviceId;
string deviceKey;
byte[] secretBytes;
byte[] ivBytes;
FileInputStream fileInputStream = null;
CipherInputStream cipherInputStream = null;
ObjectInputStream objectInputStream = null;
try
{
deviceId = sharedPreferences.GetString(AppConstants.LOGIN_CREDENTIAL_DEVICE_ID_KEY, "").Replace("-","");
deviceId = sharedPreferences.GetString(AppConstants.LOGIN_CREDENTIAL_DEVICE_KEY_KEY, "").Replace("-", "");
secretBytes = System.Text.Encoding.UTF8.GetBytes(deviceId.Substring(0, 16));
ivBytes = System.Text.Encoding.UTF8.GetBytes(deviceId.Substring(deviceId.Length - 16, deviceId.Length));
Stream fileStream = OpenFileInput(file.Name);
SecretKeySpec secretKeySpec = new SecretKeySpec(secretBytes, "AES");
IvParameterSpec ivSpec = new IvParameterSpec(secretBytes);
Cipher cipher = Cipher.GetInstance("AES/CBC/PKCS5Padding");
cipher.Init(CipherMode.DecryptMode, secretKeySpec, ivSpec);
cipherInputStream = new CipherInputStream(fileStream,cipher);
objectInputStream = new ObjectInputStream(cipherInputStream); <- In this parte i have a error because not is possible to convert CipherInputStream to Stream
這是與例子
Encryption and Decryption Support in .NET and Android