(Delphi DLL) Verify XML Digital Signature

Verifies XML signatures in an XML file.

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, XmlDSig, StringBuilder;

...

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

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

sbXml := CkStringBuilder_Create();
success := CkStringBuilder_LoadFile(sbXml,'qa_data/xml_dsig_verify/csioz_sample.xml','utf-8');
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to load XML file.');
    Exit;
  end;

dsig := CkXmlDSig_Create();

// First load the XML containing the signatures to be verified.
success := CkXmlDSig_LoadSignatureSb(dsig,sbXml);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkXmlDSig__lastErrorText(dsig));
    Exit;
  end;

// It's possible that an XML document can contain multiple signatures.
// Each can be verified as follows:
i := 0;
while i < CkXmlDSig_getNumSignatures(dsig) do
  begin
    // Select the Nth signature by setting the Selector property.
    CkXmlDSig_putSelector(dsig,i);

    // The bVerifyReferenceDigests argument determines if we want
    // to also verify each reference digest.  If set to False,
    // then only the SignedInfo part of the Signature is verified.
    bVerifyReferenceDigests := True;
    bVerified := CkXmlDSig_VerifySignature(dsig,bVerifyReferenceDigests);
    Memo1.Lines.Add('Signature ' + IntToStr(i + 1) + ' verified = ' + IntToStr(Ord(bVerified)));

    i := i + 1;
  end;

CkStringBuilder_Dispose(sbXml);
CkXmlDSig_Dispose(dsig);

end;