public async Task<string> Decrypt(IBuffer buffProtected, BinaryStringEncoding encoding)
{
try
{
// Create a DataProtectionProvider object.
DataProtectionProvider Provider = new DataProtectionProvider();
// Create a random access stream to contain the encrypted message.
InMemoryRandomAccessStream inputData = new InMemoryRandomAccessStream();
// Create a random access stream to contain the decrypted data.
InMemoryRandomAccessStream unprotectedData = new InMemoryRandomAccessStream();
// Retrieve an IOutputStream object and fill it with the input (encrypted) data.
IOutputStream outputStream = inputData.GetOutputStreamAt(0);
DataWriter writer = new DataWriter(outputStream);
writer.WriteBuffer(buffProtected);
await writer.StoreAsync();
await outputStream.FlushAsync();
// Retrieve an IInputStream object from which you can read the input (encrypted) data.
IInputStream source = inputData.GetInputStreamAt(0);
// Retrieve an IOutputStream object and fill it with decrypted data.
IOutputStream dest = unprotectedData.GetOutputStreamAt(0);
await Provider.UnprotectStreamAsync(source, dest);
await dest.FlushAsync();
// Write the decrypted data to an IBuffer object.
DataReader reader2 = new DataReader(unprotectedData.GetInputStreamAt(0));
await reader2.LoadAsync((uint)unprotectedData.Size);
IBuffer buffUnprotectedData = reader2.ReadBuffer((uint)unprotectedData.Size);
// Convert the IBuffer object to a string using the same encoding that was
// used previously to conver the plaintext string (before encryption) to an
// IBuffer object.
String strUnprotected = CryptographicBuffer.ConvertBinaryToString(encoding, buffUnprotectedData);
// Return the decrypted data.
return strUnprotected;
}
catch (Exception ex)
{
App.Telemetry.TrackException(ex);
return "";
}
}
