(Delphi DLL) Swift Alliance LAU XML Signature

Calculating the LAU for Swift Alliance File Act XML using HMAC SHA256. (The XML signature, also referred to as Local Authentication (LAU), is computed using the algorithm HMAC based on SHA-256.)

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, StringBuilder;

...

procedure TForm1.Button1Click(Sender: TObject);
var
sbXml: HCkStringBuilder;
success: Boolean;
numReplaced: Integer;
gen: HCkXmlDSigGen;

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

// We begin with the following XML:

// <?xml version="1.0" encoding="UTF-8"?>
// <Saa:DataPDU xmlns:Saa="urn:swift:saa:xsd:saa.2.0" xmlns:Sw="urn:swift:snl:ns.Sw" xmlns:SwInt="urn:swift:snl:ns.SwInt" xmlns:SwGbl="urn:swift:snl:ns.SwGbl" xmlns:SwSec="urn:swift:snl:ns.SwSec">
//     <Saa:Revision>2.0.6</Saa:Revision>
//     <Saa:Header>
//         <Saa:Message>
//             <Saa:SenderReference>Ref760FA1234</Saa:SenderReference>
//             <Saa:MessageIdentifier>tsrv.fin.mt7xx.gteesstandbys</Saa:MessageIdentifier>
//             <Saa:Format>File</Saa:Format>
//             <Saa:SubFormat>Input</Saa:SubFormat>
//             <Saa:Sender>
//                 <Saa:DN>cn=su8,o=ptsqgbbb,o=swift</Saa:DN>
//                 <Saa:FullName>
//                     <Saa:X1>PTSQGBBBXXX</Saa:X1>
//                 </Saa:FullName>
//             </Saa:Sender>
//             <Saa:Receiver>
//                 <Saa:DN>cn=abc,ou=saa,o=xxx,o=swift</Saa:DN>
//                 <Saa:FullName>
//                     <Saa:X1>PTSXXXXXXXX</Saa:X1>
//                     <Saa:X2>saa</Saa:X2>
//                 </Saa:FullName>
//             </Saa:Receiver>
//             <Saa:InterfaceInfo>
//                 <Saa:UserReference>CRE...</Saa:UserReference>
//                 <Saa:MessageCreator>ApplicationInterface</Saa:MessageCreator>
//                 <Saa:MessageContext>Original</Saa:MessageContext>
//                 <Saa:MessageNature>Financial</Saa:MessageNature>
//             </Saa:InterfaceInfo>
//             <Saa:NetworkInfo>
//                 <Saa:Priority>Normal</Saa:Priority>
//                 <Saa:IsPossibleDuplicate>true</Saa:IsPossibleDuplicate>
//                 <Saa:Service>swift.corp.fast!x</Saa:Service>
//                 <Saa:Network>Application</Saa:Network>
//                 <Saa:SessionNr>0080</Saa:SessionNr>
//                 <Saa:SeqNr>000001</Saa:SeqNr>
//                 <Saa:SWIFTNetNetworkInfo>
//                     <Saa:RequestType>tsrv.fin.mt7xx.gteesstandbys</Saa:RequestType>
//                     <Saa:Reference>2f949999-d32e-49eb-9999-9a819b9b9c0d</Saa:Reference>
//                     <Saa:FileInfo>SwCompression=Zip</Saa:FileInfo>
//                 </Saa:SWIFTNetNetworkInfo>
//             </Saa:NetworkInfo>
//             <Saa:SecurityInfo>
//                 <Saa:SWIFTNetSecurityInfo>
//                     <Saa:FileDigestAlgorithm>SHA-256</Saa:FileDigestAlgorithm>
//                     <Saa:FileDigestValue>9tnnjIgsowPSU+ehm8Rb0J5TvZIvhCYnySzFkpur1aw=</Saa:FileDigestValue>
//                 </Saa:SWIFTNetSecurityInfo>
//             </Saa:SecurityInfo>
//             <Saa:FileLogicalName>Payload.ZIP</Saa:FileLogicalName>
//             <Saa:ExpiryDateTime>20210712074808</Saa:ExpiryDateTime>
//         </Saa:Message>
//     </Saa:Header>
//     <Saa:Body>Payload.ZIP</Saa:Body>
// </Saa:DataPDU>

// Load the XML file to be signed.
sbXml := CkStringBuilder_Create();
success := CkStringBuilder_LoadFile(sbXml,'c:/someDir/fileToSign.xml','utf-8');
if (success = False) then
  begin
    Memo1.Lines.Add('Failed to load XML file.');
    Exit;
  end;

// We need to add a "LAU" XML element just before the "</Saa:DataPDU>"
numReplaced := CkStringBuilder_Replace(sbXml,'</Saa:DataPDU>','<LAU xmlns="urn:swift:saa:xsd:saa.2.0"></LAU></Saa:DataPDU>');

gen := CkXmlDSigGen_Create();
CkXmlDSigGen_putSigLocation(gen,'Saa:DataPDU|LAU');
CkXmlDSigGen_putSigLocationMod(gen,0);
CkXmlDSigGen_putSigNamespacePrefix(gen,'ds');
CkXmlDSigGen_putSigNamespaceUri(gen,'http://www.w3.org/2000/09/xmldsig#');
CkXmlDSigGen_putSignedInfoCanonAlg(gen,'EXCL_C14N');
CkXmlDSigGen_putSignedInfoDigestMethod(gen,'sha256');
CkXmlDSigGen_putBehaviors(gen,'CompactSignedXml');

// Sign the entire document.
CkXmlDSigGen_AddSameDocRef(gen,'','sha256','EXCL_C14N','','');

// Set our HMAC key
CkXmlDSigGen_SetHmacKey(gen,'Abcdef0123456789Abcdef0123456789','ascii');

// Sign the XML:
success := CkXmlDSigGen_CreateXmlDSigSb(gen,sbXml);
if (success = False) then
  begin
    Memo1.Lines.Add(CkXmlDSigGen__lastErrorText(gen));
    Exit;
  end;

// Examine the signed XML
Memo1.Lines.Add(CkStringBuilder__getAsString(sbXml));

// Save the signed XML to a file.
success := CkStringBuilder_WriteFile(sbXml,'c:/someDir/signedFile.xml','utf-8',False);

CkStringBuilder_Dispose(sbXml);
CkXmlDSigGen_Dispose(gen);

end;