/// <summary>
/// Meine Nachricht holen
/// </summary>
/// <returns>Nachricht(ViewMessage)</returns>
public async Task <Models.ViewMessage> getMessage()
{
try
{
var request = new Models.GetMessageRequest();
//Unix-Timestamp erstellen
request.timestamp = Convert.ToString(Util.UnixTimeNow());
//Anfrage signieren
request.dig_sig = EncryptLogic.createSignGetMessageRequest(request.timestamp, user.Username, user.privatekey);
HttpResponseMessage response = await client.PatchAsJsonAsync("/" + user.Username + "/message", request);
if (response.IsSuccessStatusCode)
{
Models.Message msg_response = await response.Content.ReadAsAsync <Models.Message>();
//PublicKey vom Absender holen
string publickey = await getPublicKeyFromUser(msg_response.sender);
//Nachricht prüfen
if (!EncryptLogic.verfiyInnerEnvelope(msg_response, publickey))
{
throw new Exception("Die Nachricht ist nicht verifiziert.");
}
//Key_recipient_enc(Symmetrischer Schlüssel verschlüsselt) entschlüsseln
byte[] key_recipient_enc = Convert.FromBase64String(msg_response.key_recipient_enc);
byte[] key_recipient = EncryptLogic.toDecryptKeyRecipient(key_recipient_enc, user.privatekey);
//IV
byte[] iv = Convert.FromBase64String(msg_response.iv);
//Cipher(verschlüsselte Nachricht) entschlüsseln
byte[] cipher_bytes = Convert.FromBase64String(msg_response.cipher);
string msg_dec = EncryptLogic.toDecryptMessage(cipher_bytes, key_recipient, iv);
var vm = new Models.ViewMessage();
vm.sender = msg_response.sender;
vm.content = msg_dec;
return(vm);
}
else
{
throw new HttpRequestException("URL:" + response.RequestMessage.RequestUri.AbsolutePath
+ Environment.NewLine +
"HTTP-Statuscode: " + (int)response.StatusCode + " - " + response.StatusCode);
}
} catch (Exception ex) {
Util.Log(ex.Message);
}
return(null);
}
