(Xojo Plugin) 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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.
Dim sbXml As New Chilkat.StringBuilder
Dim success As Boolean
success = sbXml.LoadFile("c:/someDir/fileToSign.xml","utf-8")
If (success = False) Then
    System.DebugLog("Failed to load XML file.")
    Return
End If

// We need to add a "LAU" XML element just before the "</Saa:DataPDU>"
Dim numReplaced As Int32
numReplaced = sbXml.Replace("</Saa:DataPDU>","<LAU xmlns=""urn:swift:saa:xsd:saa.2.0""></LAU></Saa:DataPDU>")

Dim gen As 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.
success = gen.AddSameDocRef("","sha256","EXCL_C14N","","")

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

// Sign the XML:
success = gen.CreateXmlDSigSb(sbXml)
If (success = False) Then
    System.DebugLog(gen.LastErrorText)
    Return
End If

// Examine the signed XML
System.DebugLog(sbXml.GetAsString())

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