Lazarus Pascal

Sign String to create a CAdES-T Signature, using HTTP Proxy to Access Timestamp Server

This example will sign a string to create a CAdEST-T signature. It will use an HTTP proxy to access the timestamp server. Lazarus Pascal

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Http,
  Chilkat.BinData,
  Chilkat.Cert,
  Chilkat.JsonObject,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  crypt: TCrypt2;
  cert: TCert;
  attrs: TJsonObject;
  strToSign: string;
  bd: TBinData;
  http: THttp;

begin
  success := False;

  crypt := TCrypt2.Create;

  cert := TCert.Create;
  cert.SmartCardPin := '123456';
  success := cert.LoadFromSmartcard('');
  if (success <> True) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  success := crypt.SetSigningCert(cert);

  //  Use SHA-256 rather than the default of SHA-1
  crypt.HashAlgorithm := 'sha256';

  //  Create JSON that tells Chilkat what signing attributes to include:
  attrs := TJsonObject.Create;
  attrs.UpdateBool('contentType',True);
  attrs.UpdateBool('signingTime',True);
  attrs.UpdateBool('messageDigest',True);
  attrs.UpdateBool('signingCertificateV2',True);

  //  A CAdES-T signature is one that includes a timestampToken created by an online TSA (time stamping authority).
  //  We must include the TSA's URL, as well as a few options to indicate what is desired.
  //  Except for the TSA URL, the options shown here are typically what you would need.
  attrs.UpdateBool('timestampToken.enabled',True);
  attrs.UpdateString('timestampToken.tsaUrl','https://freetsa.org/tsr');
  attrs.UpdateBool('timestampToken.addNonce',False);
  attrs.UpdateBool('timestampToken.requestTsaCert',True);
  attrs.UpdateString('timestampToken.hashAlg','sha256');

  crypt.SigningAttributes := attrs.Emit();

  strToSign := 'Hello World!';

  bd := TBinData.Create;
  bd.AppendString(strToSign,'utf-8');

  //  -------------------------------------------------------------------------
  //  The purpose of this example is to show how an HTTP object with custom
  //  settings can be used to access the Internet when signing.
  //  Access to the Internet is needed to communicate with the timestamp server.
  http := THttp.Create;
  //  This can be a domain name, hostname, or IP address.
  http.ProxyDomain := '172.16.16.56';
  http.ProxyPort := 808;
  http.ProxyLogin := 'myProxyLogin';
  http.ProxyPassword := 'myProxyPassword';
  crypt.SetTsaHttpObj(http);
  //  -------------------------------------------------------------------------

  //  This creates the CAdES-T signature.  During the signature creation, it
  //  communicates with the TSA to get a timestampToken.
  //  The contents of bd are signed and replaced with the CAdES-T signature (which embeds the original content).
  success := crypt.OpaqueSignBd(bd);
  if (success <> True) then
    begin
      WriteLn(crypt.LastErrorText);
      Exit;
    end;

  //  Get the signature in base64 format:
  WriteLn(bd.GetEncoded('base64_mime'));

  WriteLn('Success.');


  crypt.Free;
  cert.Free;
  attrs.Free;
  bd.Free;
  http.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.