Delphi DLL

Verify XML Digital Signature

See more XML Digital Signatures Examples

Verifies XML signatures in an XML file. Delphi 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
success: Boolean;
sbXml: HCkStringBuilder;
dsig: HCkXmlDSig;
i: Integer;
bVerifyReferenceDigests: Boolean;
bVerified: Boolean;

begin
success := False;

// 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;