(Node.js) 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.)

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // 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.
    var sbXml = new chilkat.StringBuilder();
    var success = sbXml.LoadFile("c:/someDir/fileToSign.xml","utf-8");
    if (success == false) {
        console.log("Failed to load XML file.");
        return;
    }

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

    var gen = new chilkat.XmlDSigGen();
    gen.SigLocation = "Saa:DataPDU|LAU";
    gen.SigLocationMod = 0;
    gen.SigNamespacePrefix = "ds";
    gen.SigNamespaceUri = "http://www.w3.org/2000/09/xmldsig#";
    gen.SignedInfoCanonAlg = "EXCL_C14N";
    gen.SignedInfoDigestMethod = "sha256";
    gen.Behaviors = "CompactSignedXml";

    // Sign the entire document.
    gen.AddSameDocRef("","sha256","EXCL_C14N","","");

    // Set our HMAC key
    gen.SetHmacKey("Abcdef0123456789Abcdef0123456789","ascii");

    // Sign the XML:
    success = gen.CreateXmlDSigSb(sbXml);
    if (success == false) {
        console.log(gen.LastErrorText);
        return;
    }

    // Examine the signed XML
    console.log(sbXml.GetAsString());

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

}

chilkatExample();