static Task <string> PlatformGetAsync(string key)
{
var context = Platform.AppContext;
string defaultEncStr = null;
var encStr = Preferences.Get(Utils.Md5Hash(key), defaultEncStr, Alias);
string decryptedData = null;
if (!string.IsNullOrEmpty(encStr))
{
var encData = Convert.FromBase64String(encStr);
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
try
{
decryptedData = ks.Decrypt(encData);
}
catch (AEADBadTagException)
{
System.Diagnostics.Debug.WriteLine($"Unable to decrypt key, {key}, which is likely due to an app uninstall. Removing old key and returning null.");
PlatformRemove(key);
}
}
return(Task.FromResult(decryptedData));
}
static Task <string> PlatformGetAsync(string key)
{
var context = Platform.AppContext;
string encStr = default;
var foundLegacyValue = false;
if (LegacyKeyHashFallback)
{
// If not found, could have been previously stored with md5 key
if (!Preferences.ContainsKey(key, Alias))
{
// If previously stored with md5 key, save with new key
var md5Key = Md5Hash(key);
if (Preferences.ContainsKey(md5Key, Alias))
{
encStr = Preferences.Get(md5Key, null, Alias);
Preferences.Set(key, encStr, Alias);
foundLegacyValue = true;
try
{
Preferences.Remove(md5Key, Alias);
}
catch
{
}
}
}
}
if (!foundLegacyValue)
{
encStr = Preferences.Get(key, null, Alias);
}
string decryptedData = null;
if (!string.IsNullOrEmpty(encStr))
{
try
{
var encData = Convert.FromBase64String(encStr);
lock (locker)
{
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
decryptedData = ks.Decrypt(encData);
}
}
catch (AEADBadTagException)
{
System.Diagnostics.Debug.WriteLine($"Unable to decrypt key, {key}, which is likely due to an app uninstall. Removing old key and returning null.");
Remove(key);
}
}
return(Task.FromResult(decryptedData));
}
static Task PlatformSetAsync(string key, string data)
{
var context = Platform.AppContext;
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
var encryptedData = ks.Encrypt(data);
var encStr = Convert.ToBase64String(encryptedData);
Preferences.Set(Utils.Md5Hash(key), encStr, Alias);
return(Task.CompletedTask);
}
static Task <string> PlatformGetAsync(string key)
{
var context = Platform.CurrentContext;
string encStr;
using (var prefs = context.GetSharedPreferences(Alias, FileCreationMode.Private))
encStr = prefs.GetString(Utils.Md5Hash(key), null);
var encData = Convert.FromBase64String(encStr);
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
var decryptedData = ks.Decrypt(encData);
return(Task.FromResult(decryptedData));
}
static Task PlatformSetAsync(string key, string data)
{
var context = Platform.AppContext;
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
var encryptedData = ks.Encrypt(data);
using (var prefs = context.GetSharedPreferences(Alias, FileCreationMode.Private))
using (var prefsEditor = prefs.Edit())
{
var encStr = Convert.ToBase64String(encryptedData);
prefsEditor.PutString(Utils.Md5Hash(key), encStr);
prefsEditor.Commit();
}
return(Task.CompletedTask);
}
static Task <string> PlatformGetAsync(string key)
{
var context = Platform.AppContext;
string defaultEncStr = null;
var encStr = Preferences.Get(Utils.Md5Hash(key), defaultEncStr, Alias);
string decryptedData = null;
if (!string.IsNullOrEmpty(encStr))
{
var encData = Convert.FromBase64String(encStr);
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
decryptedData = ks.Decrypt(encData);
}
return(Task.FromResult(decryptedData));
}
static Task PlatformSetAsync(string key, string data)
{
var context = Platform.AppContext;
byte[] encryptedData = null;
lock (locker)
{
var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
encryptedData = ks.Encrypt(data);
}
var encStr = Convert.ToBase64String(encryptedData);
Preferences.Set(key, encStr, Alias);
CheckForAndRemoveLegacyKey(key);
return(Task.CompletedTask);
}