??? TLS ?? ??

.NET Framework 4.7 ??????? ????? TLS 1.2? ?????. ??? ?? ?? ?? ??? ?? TLS ??? ???? ?? ?????. ??? ??? ????.

?? 1: ???? ??

? ???? ????? ???? GetRequestStream() ?? GetResponseStream() ??? ???? ?? TlsStream ??? ????? ??? ?????. TlsStream ???? SslState ??? ?? ???? ???? SslProtocol ??? ???????.

using System.IO.Compression;
using System.Net;
using System.Reflection;
using System.Security.Authentication;

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(decodedUri);
using (Stream requestStream = request.GetRequestStream())
{
    SslProtocols sslProtocol = ExtractSslProtocol(requestStream);
    // 檢查SSL版本，如有必要采取適當?shù)拇胧?}

private SslProtocols ExtractSslProtocol(Stream stream)
{
    BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.NonPublic;
    Stream metaStream = stream;

    // 處理GZip或Deflate流
    if (stream is GZipStream) metaStream = (stream as GZipStream).BaseStream;
    else if (stream is DeflateStream) metaStream = (stream as DeflateStream).BaseStream;

    var tlsStream = metaStream.GetType().GetProperty("Connection", bindingFlags).GetValue(metaStream);
    if (!(bool)tlsStream.GetType().GetProperty("UsingSecureStream", bindingFlags).GetValue(tlsStream)) return SslProtocols.None;

    var tlsState = tlsStream.GetType().GetField("m_Worker", bindingFlags).GetValue(tlsStream);
    return (SslProtocols)tlsState.GetType().GetProperty("SslProtocol", bindingFlags).GetValue(tlsState);
}

?? 2: TcpClient ??

?? TcpClient ???? ???? TCP ??? ??? ? ????. TcpClient? SslStream? ?? ???? ????? ??? TLS ??? ??? ? ????. ? ??? HTTP ??? ???? ?? TLS ??? ???? ?? ?? ?????.

TlsInfo tlsInfo = null;
IPHostEntry dnsHost = await Dns.GetHostEntryAsync(HostURI.Host);
using (TcpClient client = new TcpClient(dnsHost.HostName, 443))
{
    using (SslStream sslStream = new SslStream(client.GetStream(), false,
                                               TlsValidationCallback, null))
    {
        sslstream.AuthenticateAsClient(dnsHost.HostName, null,
                                      (SslProtocols)ServicePointManager.SecurityProtocol, false);
        tlsInfo = new TlsInfo(sslStream);
    }
}

public class TlsInfo
{
    public TlsInfo(SslStream secStream)
    {
        this.ProtocolVersion = secStream.SslProtocol;
    }

    public SslProtocols ProtocolVersion { get; set; }
}

? ?? ?? ?? ?? HTTP ?? ?? ??? TLS ??? ???? ??? ????? ?? ?? ??? ?? ??? ??? ?? ? ????.

? ??? .NET Framework?? ??? TLS ??? ???? ??? ??????? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!