public async Task <T> ShowQrForAJsonResult <T>(string prefix, Task <string> qrUserContentJson) where T : class
{
using (var pcKey = CngKey.Create(CngAlgorithm.ECDiffieHellmanP384))
{
using (var comm = NewClientListener())
{
var qrBody = QrBuilder.BuildQrBody(comm, EncryptionUtils.EccPublicToPem(pcKey));
await _qrDisplayer.ShowQr(prefix, qrBody.ToArray());
using (var commStream = await comm.GetStream())
{
await _qrDisplayer.HideQr();
var aes256Key = ClientListener.CompleteEcdhFromStream(pcKey, commStream);
qrUserContentJson.Start();
var content = await qrUserContentJson;
if (content == null)
{
return(null);
}
ClientListener.SendEncrypted(Encoding.UTF8.GetBytes(content), aes256Key, commStream);
return(JsonConvert.DeserializeObject <T>(ClientListener.DecryptMessage(aes256Key, commStream)));
}
}
}
}
