B4X

Verify HMAC XML Digital Signature

See more XML Digital Signatures Examples

Demonstrates how to validate an XML digital signature signed with an HMAC key. B4X

Dim success As Boolean = False

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

'  The XML containing the Signature to be verified contains the following:

'  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
'  <collection Id="root">
'  	<album>
'  		<title>Questions, unanswered</title>
'  		<artist>Steve and the flubberblubs</artist>
'  		<year>1989</year>
'  		<t:tracks xmlns:t="http://test.xades4j/tracks">
'  			<t:song length="4:05" tracknumber="1">
'  				<t:title>What do you know?</t:title>
'  				<t:artist>Steve and the flubberblubs</t:artist>
'  				<t:lastplayed>2006-10-17-08:31</t:lastplayed>
'  			</t:song>
'  			<t:song length="3:45" tracknumber="2">
'  				<t:title>Who do you know?</t:title>
'  				<t:artist>Steve and the flubberblubs</t:artist>
'  				<t:lastplayed>2006-10-17-08:35</t:lastplayed>
'  			</t:song>
'  			<t:song length="5:14" tracknumber="3">
'  				<t:title>When do you know?</t:title>
'  				<t:artist>Steve and the flubberblubs</t:artist>
'  				<t:lastplayed>2006-10-17-08:39</t:lastplayed>
'  			</t:song>
'  			<t:song length="4:19" tracknumber="4">
'  				<t:title>Do you know?</t:title>
'  				<t:artist>Steve and the flubberblubs</t:artist>
'  				<t:lastplayed>2006-10-17-08:44</t:lastplayed>
'  			</t:song>
'  		</t:tracks>
'  	</album>
'  <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#hmac-sha256"/><ds:Reference URI="#root"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>rD/g8soqKz8EiPUBhEWfcQacS0ta4ULHX3dKMEH6ZoQ=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>R8dXP95VRYJBfL6d0Peogybdk27+R+JIfX8jnVu0NOI=</ds:SignatureValue></ds:Signature></collection>

'  The above XML is available at https://www.chilkatsoft.com/exampleData/hmacSigned.xml
'  First fetch the XML..

Dim url As String = "https://www.chilkatsoft.com/exampleData/hmacSigned.xml"
Dim http As ChilkatHttp
http.Initialize("http")
Dim sbXml As ChilkatStringBuilder
sbXml.Initialize
success = http.QuickGetSb(url, sbXml)
If success <> True Then
    Log(http.LastErrorText)
    Return
End If


Dim verifier As ChilkatXmlDSig
verifier.Initialize

'  Load the XML containing the signature to be verified.
success = verifier.LoadSignatureSb(sbXml)
If success <> True Then
    Log(verifier.LastErrorText)
    Return
End If


'  Provide the HMAC key
'  The HMAC key for this signature is the us-ascii bytes of the string "secret",
'  It can be set in any of the following ways (and also more ways not shown here..)
verifier.SetHmacKey("secret", "ascii")
'  or
verifier.SetHmacKey("c2VjcmV0", "base64")
'  or
verifier.SetHmacKey("736563726574", "hex")

'  Verify the signature
Dim bVerified As Boolean = verifier.VerifySignature(True)
Log("Signature verified = " & bVerified)