public App()
{
InitializeComponent();
if (!string.IsNullOrEmpty(Preferences.Get("accesstoken", "")))
{
MainPage = new MasterPage();
}
else if (string.IsNullOrEmpty(Preferences.Get("useremail", "")) && string.IsNullOrEmpty(Preferences.Get("password", "")))
{
MainPage = new NavigationPage(new LoginPage());
}
}
static VersionTracking()
{
IsFirstLaunchEver = !Preferences.ContainsKey(versionsKey, sharedName) || !Preferences.ContainsKey(buildsKey, sharedName);
if (IsFirstLaunchEver)
{
versionTrail = new Dictionary <string, List <string> >
{
{ versionsKey, new List <string>() },
{ buildsKey, new List <string>() }
};
}
else
{
versionTrail = new Dictionary <string, List <string> >
{
{ versionsKey, ReadHistory(versionsKey).ToList() },
{ buildsKey, ReadHistory(buildsKey).ToList() }
};
}
IsFirstLaunchForCurrentVersion = !versionTrail[versionsKey].Contains(CurrentVersion);
if (IsFirstLaunchForCurrentVersion)
{
versionTrail[versionsKey].Add(CurrentVersion);
}
IsFirstLaunchForCurrentBuild = !versionTrail[buildsKey].Contains(CurrentBuild);
if (IsFirstLaunchForCurrentBuild)
{
versionTrail[buildsKey].Add(CurrentBuild);
}
if (IsFirstLaunchForCurrentVersion || IsFirstLaunchForCurrentBuild)
{
WriteHistory(versionsKey, versionTrail[versionsKey]);
WriteHistory(buildsKey, versionTrail[buildsKey]);
}
}
static void WriteHistory(string key, IEnumerable <string> history)
=> Preferences.Set(key, string.Join("|", history), sharedName);
static string[] ReadHistory(string key)
=> Preferences.Get(key, null, sharedName)?.Split(new[] { '|' }, StringSplitOptions.RemoveEmptyEntries) ?? new string[0];
static void PlatformRemoveAll() => Preferences.Clear(Alias);
ISecretKey GetKey()
{
// check to see if we need to get our key from past-versions or newer versions.
// we want to use symmetric if we are >= 23 or we didn't set it previously.
useSymmetric = Preferences.Get(useSymmetricPreferenceKey, Platform.HasApiLevel(BuildVersionCodes.M), SecureStorage.Alias);
// If >= API 23 we can use the KeyStore's symmetric key
if (useSymmetric && !alwaysUseAsymmetricKey)
{
return(GetSymmetricKey());
}
// NOTE: KeyStore in < API 23 can only store asymmetric keys
// specifically, only RSA/ECB/PKCS1Padding
// So we will wrap our symmetric AES key we just generated
// with this and save the encrypted/wrapped key out to
// preferences for future use.
// ECB should be fine in this case as the AES key should be
// contained in one block.
// Get the asymmetric key pair
var keyPair = GetAsymmetricKeyPair();
var existingKeyStr = Preferences.Get(prefsMasterKey, null, alias);
if (!string.IsNullOrEmpty(existingKeyStr))
{
try
{
var wrappedKey = Convert.FromBase64String(existingKeyStr);
var unwrappedKey = UnwrapKey(wrappedKey, keyPair.Private);
var kp = unwrappedKey.JavaCast <ISecretKey>();
return(kp);
}
catch (InvalidKeyException ikEx)
{
System.Diagnostics.Debug.WriteLine($"Unable to unwrap key: Invalid Key. This may be caused by system backup or upgrades. All secure storage items will now be removed. {ikEx.Message}");
}
catch (IllegalBlockSizeException ibsEx)
{
System.Diagnostics.Debug.WriteLine($"Unable to unwrap key: Illegal Block Size. This may be caused by system backup or upgrades. All secure storage items will now be removed. {ibsEx.Message}");
}
catch (BadPaddingException paddingEx)
{
System.Diagnostics.Debug.WriteLine($"Unable to unwrap key: Bad Padding. This may be caused by system backup or upgrades. All secure storage items will now be removed. {paddingEx.Message}");
}
SecureStorage.RemoveAll();
}
var keyGenerator = KeyGenerator.GetInstance(aesAlgorithm);
var defSymmetricKey = keyGenerator.GenerateKey();
var newWrappedKey = WrapKey(defSymmetricKey, keyPair.Public);
Preferences.Set(prefsMasterKey, Convert.ToBase64String(newWrappedKey), alias);
return(defSymmetricKey);
}
