/// <summary>
/// Connects the <see cref="Client"/> asynchronously to the specified TCP port on the specified host.
/// </summary>
/// <param name="host">The name or IP address of the host.</param>
/// <param name="port">The port to connect to.</param>
/// <param name="submitCryptographicData">Set to "true" to use <see cref="Aes"/> encryption for all communications.</param>
/// <remarks>Using <paramref name="submitCryptographicData" /> requires the <see cref="Client"/> to have valid <see cref="CryptographicData"/> set.</remarks>
/// <returns>Returns a <see cref="Task"/> that represents the asynchronous connect operation.</returns>
public async Task ConnectAsync(string host, int port, bool submitCryptographicData)
{
await client.ConnectAsync(host, port);
reader = new StreamReader(client.GetStream());
writer = new StreamWriter(client.GetStream());
if (submitCryptographicData && CryptographicData.IsValid())
{
var @params = await ReadAsync <RSAParameters>();
var encrypted = CryptographyProvider.Instance.RSAEncrypt(JsonConvert.SerializeObject(CryptographicData), @params);
await WriteRawAsync(encrypted);
SessionId = Guid.Parse(await ReadAsync());
}
OnConnected(this, new ConnectedEventArgs());
}
/// <summary>
/// Writes a line of characters asynchronously to the stream.
/// </summary>
/// <param name="s">The string to write to the stream.</param>
/// <returns>Returns a <see cref="Task"/> that represents the asynchronous write operation.</returns>
/// <remarks>The written string will be encrypted if the <see cref="Client"/> has valid <see cref="CryptographicData"/>.<para>Use the <see cref="WriteRawAsync"/> function to always write data unhandled.</para></remarks>
public async Task WriteAsync(string s)
{
if (CryptographicData == null || !CryptographicData.IsValid())
{
await WriteRawAsync(s);
}
else
{
var encrypted = await CryptographyProvider.Instance.AesEncryptAsync(s, CryptographicData);
var signature = CryptographyProvider.Instance.HmacCreateSignature(encrypted, CryptographicData);
await writer.WriteLineAsync($"{encrypted}|{signature}");
await writer.FlushAsync();
}
}
/// <summary>
/// Reads a line of characters asynchronously from the stream and returns the data as a string.
/// </summary>
/// <returns>Returns a <see cref="Task"/> that represents the asynchronous read operation. The value of the TResult parameter contains the next line from the stream.</returns>
/// <remarks>The returned string will be decrypted if the <see cref="Client"/> has valid <see cref="CryptographicData"/> and the data seems encrypted (contains a "|").<para>Use the <see cref="ReadRawAsync"/> function to always get unhandled data.</para></remarks>
/// <exception cref="ClientDisconnectedException">The <see cref="Client"/> isn't connected.</exception>
/// <exception cref="HmacSignatureInvalidException">The signature is invalid or the data isn't encrypted but contains a "|".</exception>
public async Task <string> ReadAsync()
{
if (CryptographicData == null || !CryptographicData.IsValid())
{
return(await ReadRawAsync());
}
var data = await ReadRawAsync();
if (!data.Contains("|"))
{
return(data);
}
var encrypted = data.Split('|')[0];
var signature = data.Split('|')[1];
if (!CryptographyProvider.Instance.HmacValidateSignature(encrypted, signature, CryptographicData))
{
throw new HmacSignatureInvalidException();
}
return(await CryptographyProvider.Instance.AesDecryptAsync(encrypted, CryptographicData));
}