(Delphi DLL) Get Certificates within XML Signature

Demonstrates how to get the certificates contained within an XML signature.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, StringBuilder, StringArray, Cert, XmlDSig;

...

procedure TForm1.Button1Click(Sender: TObject);
var
sbXml: HCkStringBuilder;
success: Boolean;
dsig: HCkXmlDSig;
i: Integer;
saCerts: HCkStringArray;
cert: HCkCert;
bVerifyReferenceDigests: Boolean;
bVerified: Boolean;
j: Integer;

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

sbXml := CkStringBuilder_Create();

// Load XML containing one or more signatures.
success := CkStringBuilder_LoadFile(sbXml,'qa_data/xml_dsig_valid_samples/multipleSigners/sp.pdf.XAdES.xml','utf-8');
if (success = False) then
  begin
    Memo1.Lines.Add('Failed to load the XML file..');
    Exit;
  end;

dsig := CkXmlDSig_Create();

// First load the XML containing the signatures to be verified.
// Note that this particular Signature already contains the RSA public key that will be used
// for verification.
success := CkXmlDSig_LoadSignatureSb(dsig,sbXml);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkXmlDSig__lastErrorText(dsig));
    Exit;
  end;

// For each signature, verify and also get the certificate(s) contained within each Signature.
i := 0;
saCerts := CkStringArray_Create();
cert := CkCert_Create();

Memo1.Lines.Add('numSignatures = ' + IntToStr(CkXmlDSig_getNumSignatures(dsig)));

while i < CkXmlDSig_getNumSignatures(dsig) do
  begin
    // Select the Nth signature by setting the Selector property.
    CkXmlDSig_putSelector(dsig,i);

    bVerifyReferenceDigests := True;
    bVerified := CkXmlDSig_VerifySignature(dsig,bVerifyReferenceDigests);
    Memo1.Lines.Add('Signature ' + IntToStr(i + 1) + ' verified = ' + IntToStr(bVerified));

    // Get the certificates embedded in this signature.
    CkStringArray_Clear(saCerts);
    success := CkXmlDSig_GetCerts(dsig,saCerts);
    if (success = True) then
      begin
        j := 0;
        while j < CkStringArray_getCount(saCerts) do
          begin
            success := CkCert_LoadFromBase64(cert,CkStringArray__getString(saCerts,j));
            if (success = True) then
              begin
                Memo1.Lines.Add('    ' + CkCert__subjectDN(cert));
              end;
            j := j + 1;
          end;

      end;

    i := i + 1;
  end;

CkStringBuilder_Dispose(sbXml);
CkXmlDSig_Dispose(dsig);
CkStringArray_Dispose(saCerts);
CkCert_Dispose(cert);

end;