Lua

Verify HMAC XML Digital Signature

See more XML Digital Signatures Examples

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

local chilkat = require("chilkat")

-- 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..

local url = "https://www.chilkatsoft.com/exampleData/hmacSigned.xml"
local http = chilkat.Http.new()
local sbXml = chilkat.StringBuilder.new()
local success = http:quick_get_sb(url, sbXml)
if not success then
    print(http.last_error_text)
    return
end

local verifier = chilkat.XmlDSig.new()

-- Load the XML containing the signature to be verified.
success = verifier:load_signature_sb(sbXml)
if not success then
    print(verifier.last_error_text)
    return
end

-- 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:set_hmac_key("secret", "ascii")
-- or
verifier:set_hmac_key("c2VjcmV0", "base64")
-- or
verifier:set_hmac_key("736563726574", "hex")

-- Verify the signature
local bVerified = verifier:verify_signature(true)
print("Signature verified = " .. tostring(bVerified))