Pascal (Lazarus/Delphi)

Create XML Signature with External Data Reference

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature where the data is external. In this case, the data is a JPG file.

This example requires Chilkat v9.5.0.69 or greater.

Pascal (Lazarus/Delphi)

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.StringBuilder,
  Chilkat.PrivateKey,
  Chilkat.XmlDSigGen,
  Chilkat.BinData;

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

procedure RunDemo;
var
  success: Boolean;
  url: string;
  http: THttp;
  sbXml: TStringBuilder;
  rsaKey: TPrivateKey;
  xmlSigGen: TXmlDSigGen;
  jpgUrl: string;
  jpgData: TBinData;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  //  This example inserts an XML signature in the following XML:

  //  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
  //  <abc>
  //    <xyz>
  //      <jpg>
  //          <name>starfish.jpg</name>
  //          <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
  //      </jpg>
  //    </xyz>
  //  </abc>

  //  The above XML is available at https://www.chilkatsoft.com/exampleData/addSignatureToThis.xml
  //  First fetch the XML:

  url := 'https://www.chilkatsoft.com/exampleData/addSignatureToThis.xml';
  http := THttp.Create;
  sbXml := TStringBuilder.Create;
  success := http.QuickGetSb(url,sbXml);
  if (success <> True) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  //  We'll use an RSA private key for signing.  
  rsaKey := TPrivateKey.Create;
  success := rsaKey.LoadPemFile('qa_data/rsa/rsaPrivKey_pkcs8.pem');
  if (success <> True) then
    begin
      WriteLn(rsaKey.LastErrorText);
      Exit;
    end;

  xmlSigGen := TXmlDSigGen.Create;

  //  Indicate were the Signature will be inserted:
  xmlSigGen.SigLocation := 'abc|xyz|jpg';

  //  Provide the RSA key to be used for signing:
  xmlSigGen.SetPrivateKey(rsaKey);

  //  Fetch the JPG image data.
  jpgUrl := 'https://www.chilkatsoft.com/images/starfish.jpg';
  jpgData := TBinData.Create;
  success := http.QuickGetBd(jpgUrl,jpgData);
  if (success <> True) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  //  Add the external data reference:
  xmlSigGen.AddExternalBinaryRef(jpgUrl,jpgData,'sha256','');

  //  Create the XML digital signature:
  success := xmlSigGen.CreateXmlDSigSb(sbXml);
  if (success <> True) then
    begin
      WriteLn(xmlSigGen.LastErrorText);
      Exit;
    end;

  //  Examine the XML that now contains the Signature:
  WriteLn(sbXml.GetAsString());

  //  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
  //  <abc>
  //    <xyz>
  //      <jpg>
  //          <name>starfish.jpg</name>
  //          <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
  //      <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/><ds:Reference URI="https://www.chilkatsoft.com/images/starfish.jpg"><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>AOU810yJV5Np/DnO29qpObqiTSTTCDvxGsX5ayiTYXI=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>ApHRr6nilNrzt3dLveC9zlPoSllaCMfHsbAwr+vYBPkHkJ4wD5LzDDhi1tSJZAAeTckmvSqIG3Wi0rgXQiSM644MD3coBFx4QgrY+GZ+XJJE2Y0Ye3VvaQBiRdUW3INGsW4GLubncgQk5JhuAQjo6O/GKpfEuYqUJj/6CLHLQwMPwbZ2043ykgzuPFoOZf6EydJMBAn1ORMvrpUn+zuA9UngOTGap6eWE4CeiNx23BRC2wSztbUjdCLcqXvgiYu/v0tBNaTcwy7b6+IFtwv/lNUUBUQJ/3p+aErzFn3wLeH3yeqpDCU0U6Dqu5SS1jYupcWWsLHJjYnj2066DPJi/g==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:RSAKeyValue><ds:Modulus>sXeRhM55P13FbpNcXAMR3olbw2Wa6keZIHu5YTZYUBTlYWId+pNiwUz3zFIEo+0IfYR0H27ybIycQO+1IIzJofUFNMAL3tZps2OKPlsjuCPls6kXpXhv/gvhux8LrCtp4PcKWqJ6QVOZKChc7WAx40qFWzHi57ueqRTv3x0kESqGg/VjsqyTEvb55psJO2RsfhLT7+YVh3hImRM3RDaJdkTkPuOxeFyT6N7VXD09329sLuS3QkUbE9zEKDnz9X3d8dEQdJhSI9ba5fxl8R7fu8pB67ElfzFml96X1jLFtzy1pzOT5Fc4ROcaqlYckVzdBq9sxezm6MYmDBjNAcibRw==</ds:Modulus><ds:Exponent>AQAB</ds:Exponent></ds:RSAKeyValue></ds:KeyValue></ds:KeyInfo></ds:Signature></jpg>
  //    </xyz>
  //  </abc>
  //  


  http.Free;
  sbXml.Free;
  rsaKey.Free;
  xmlSigGen.Free;
  jpgData.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.