(Delphi DLL) Create Enveloping XML Digital Signature

This example creates an enveloping digital signature.
An enveloping signature is where the signed data is contained within the Signature within an Object element.
This example signs non-XML text data where the XML signature constitutes the entire output.

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, XmlDSigGen, Zip, StringBuilder, BinData, PrivateKey, ZipEntry, Http;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
zipFile: HCkBinData;
keyUrl: PWideChar;
success: Boolean;
zip: HCkZip;
zipEntry: HCkZipEntry;
ecKey: HCkPrivateKey;
gen: HCkXmlDSigGen;
sbContent: HCkStringBuilder;
sbXml: HCkStringBuilder;

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

// Let's use the ECDSA private key at https://www.chilkatsoft.com/exampleData/secp256r1-key.zip
// for signing.
http := CkHttp_Create();
zipFile := CkBinData_Create();
keyUrl := 'https://www.chilkatsoft.com/exampleData/secp256r1-key.zip';

success := CkHttp_QuickGetBd(http,keyUrl,zipFile);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;
zip := CkZip_Create();
success := CkZip_OpenBd(zip,zipFile);
zipEntry := CkZip_FirstMatchingEntry(zip,'*.pem');
ecKey := CkPrivateKey_Create();
success := CkPrivateKey_LoadPem(ecKey,CkZipEntry__unzipToString(zipEntry,0,'utf-8'));
if (success <> True) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(ecKey));
    CkZipEntry_Dispose(zipEntry);
    Exit;
  end;

CkZipEntry_Dispose(zipEntry);

// ----------------------------------------------------------------------------
gen := CkXmlDSigGen_Create();

// Provide the ECDSA key to the XML Digital Signature generator
CkXmlDSigGen_SetPrivateKey(gen,ecKey);

// Add an enveloped reference to the content to be signed.
sbContent := CkStringBuilder_Create();
CkStringBuilder_Append(sbContent,'This is the content that is signed.');
CkXmlDSigGen_AddEnvelopedRef(gen,'abc123',sbContent,'sha256','C14N','');

// Generate the XML digital signature.
// Notice that in other examples, the sbXml passed to CreateXmlDSigSb
// already contains XML, and the XML signature is inserted at the location
// specified by the SigLocation property.  In this case, both SigLocation
// and sbXml are empty.  The result is that sbXml will contain just the Signature.
sbXml := CkStringBuilder_Create();
success := CkXmlDSigGen_CreateXmlDSigSb(gen,sbXml);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkXmlDSigGen__lastErrorText(gen));
    Exit;
  end;

// Examine the enveloped signature, where the data is contained within the XML Signature
Memo1.Lines.Add(CkStringBuilder__getAsString(sbXml));

// The Signature returned is compact and in a single line, like this:
// <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#ecdsa-sha256"/><ds:Reference URI="#abc123"><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>tEVrbXXjeTXjF3tIojul4/sgeEGN49E1dxr/GMs8GNE=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>/pILUshwrzgdGc4bPgp85TDfbUiM9pn8EIPNRVWKuoVEtPsv4XRthUrv9aDDvajmyl2okLwTakANgtaxO1ULMw==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:ECKeyValue xmlns="http://www.w3.org/2009/xmldsig11#"><ds:NamedCurve URI="urn:oid:1.2.840.10045.3.1.7" /><ds:PublicKey>BOVKaiLPKEDChhkA64UEBOXTv/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=</ds:PublicKey></ds:ECKeyValue></ds:KeyValue></ds:KeyInfo><ds:Object Id="abc123">This is the content that is signed.</ds:Object></ds:Signature>

// XML pretty-printed, the signature is as follows, but pretty-printing introductes whitespace that breaks the signature..

// <?xml version="1.0" encoding="utf-8" ?>
// <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#ecdsa-sha256" />
//         <ds:Reference URI="#abc123">
//             <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
//             <ds:DigestValue>tEVrbXXjeTXjF3tIojul4/sgeEGN49E1dxr/GMs8GNE=</ds:DigestValue>
//         </ds:Reference>
//     </ds:SignedInfo>
//     <ds:SignatureValue>/pILUshwrzgdGc4bPgp85TDfbUiM9pn8EIPNRVWKuoVEtPsv4XRthUrv9aDDvajmyl2okLwTakANgtaxO1ULMw==</ds:SignatureValue>
//     <ds:KeyInfo>
//         <ds:KeyValue>
//             <ds:ECKeyValue xmlns="http://www.w3.org/2009/xmldsig11#">
//                 <ds:NamedCurve URI="urn:oid:1.2.840.10045.3.1.7" />
//                 <ds:PublicKey>BOVKaiLPKEDChhkA64UEBOXTv/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=</ds:PublicKey>
//             </ds:ECKeyValue>
//         </ds:KeyValue>
//     </ds:KeyInfo>
//     <ds:Object Id="abc123">This is the content that is signed.</ds:Object>
// </ds:Signature>
// 

CkHttp_Dispose(http);
CkBinData_Dispose(zipFile);
CkZip_Dispose(zip);
CkPrivateKey_Dispose(ecKey);
CkXmlDSigGen_Dispose(gen);
CkStringBuilder_Dispose(sbContent);
CkStringBuilder_Dispose(sbXml);

end;