(Visual Basic 6.0) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

' 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.
Dim http As New ChilkatHttp
Dim zipFile As New ChilkatBinData
Dim keyUrl As String
keyUrl = "https://www.chilkatsoft.com/exampleData/secp256r1-key.zip"

Dim success As Long
success = http.QuickGetBd(keyUrl,zipFile)
If (success <> 1) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

Dim zip As New ChilkatZip
success = zip.OpenBd(zipFile)
Dim zipEntry As ChilkatZipEntry
Set zipEntry = zip.FirstMatchingEntry("*.pem")
Dim ecKey As New PrivateKey
success = ecKey.LoadPem(zipEntry.UnzipToString(0,"utf-8"))
If (success <> 1) Then
    Debug.Print ecKey.LastErrorText

    Exit Sub
End If

' ----------------------------------------------------------------------------
Dim gen As New ChilkatXmlDSigGen

' Provide the ECDSA key to the XML Digital Signature generator
success = gen.SetPrivateKey(ecKey)

' Add an enveloped reference to the content to be signed.
Dim sbContent As New ChilkatStringBuilder
success = sbContent.Append("This is the content that is signed.")
success = gen.AddEnvelopedRef("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.
Dim sbXml As New ChilkatStringBuilder
success = gen.CreateXmlDSigSb(sbXml)
If (success <> 1) Then
    Debug.Print gen.LastErrorText
    Exit Sub
End If

' Examine the enveloped signature, where the data is contained within the XML Signature
Debug.Print sbXml.GetAsString()

' 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>
'