Delphi ActiveX

Enumerate Server-Advertised Acceptable Client CAs

Demonstrates Socket.GetSslAcceptableClientCaDn, which returns a certificate-authority distinguished name advertised by a TLS server when it requests a client certificate.

Background. Valid indexes range from 0 through NumSslAcceptableClientCAs minus one. A client can use these names to select an appropriate client certificate.

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var
success: Integer;
socket: TChilkatSocket;
bTls: Integer;
maxWaitMs: Integer;
numCAs: Integer;
i: Integer;
caDn: WideString;

begin
success := 0;

socket := TChilkatSocket.Create(Self);

//  Connect to the server using TLS.
bTls := 1;
maxWaitMs := 5000;
success := socket.Connect('example.com',5000,bTls,maxWaitMs);
if (success = 0) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

//  After connecting to a server that requests a client certificate, enumerate the certificate-
//  authority distinguished names the server advertised as acceptable.
numCAs := socket.NumSslAcceptableClientCAs;

for i := 0 to numCAs - 1 do
  begin
    caDn := socket.GetSslAcceptableClientCaDn(i);
    if (socket.LastMethodSuccess = 0) then
      begin
        Memo1.Lines.Add(socket.LastErrorText);
        Exit;
      end;
    Memo1.Lines.Add(caDn);
  end;