Visual FoxPro

Verify HMAC XML Digital Signature

See more XML Digital Signatures Examples

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

LOCAL lnSuccess
LOCAL lcUrl
LOCAL loHttp
LOCAL loSbXml
LOCAL loVerifier
LOCAL lnBVerified

lnSuccess = 0

* 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..

lcUrl = "https://www.chilkatsoft.com/exampleData/hmacSigned.xml"
loHttp = CreateObject('Chilkat.Http')
loSbXml = CreateObject('Chilkat.StringBuilder')
lnSuccess = loHttp.QuickGetSb(lcUrl,loSbXml)
IF (lnSuccess <> 1) THEN
    ? loHttp.LastErrorText
    RELEASE loHttp
    RELEASE loSbXml
    CANCEL
ENDIF

loVerifier = CreateObject('Chilkat.XmlDSig')

* Load the XML containing the signature to be verified.
lnSuccess = loVerifier.LoadSignatureSb(loSbXml)
IF (lnSuccess <> 1) THEN
    ? loVerifier.LastErrorText
    RELEASE loHttp
    RELEASE loSbXml
    RELEASE loVerifier
    CANCEL
ENDIF

* 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..)
loVerifier.SetHmacKey("secret","ascii")
* or
loVerifier.SetHmacKey("c2VjcmV0","base64")
* or
loVerifier.SetHmacKey("736563726574","hex")

* Verify the signature
lnBVerified = loVerifier.VerifySignature(1)
? "Signature verified = " + STR(lnBVerified)

RELEASE loHttp
RELEASE loSbXml
RELEASE loVerifier