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Lua Requires Chilkat v9.5.0.69+

Create XML Digital Signature using a ECDSA Key

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature using a ECDSA key.

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Lua 
local chilkat = require("chilkat")

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

-- The SOAP XML to be signed in this example contains the following:

-- <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
-- <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
--     <SOAP-ENV:Header>
--         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"></wsse:Security>
--     </SOAP-ENV:Header>
--     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
--         <z:FooBar xmlns:z="http://example.com" />
--     </SOAP-ENV:Body>
-- </SOAP-ENV:Envelope>
--

-- The above XML is available at https://www.chilkatsoft.com/exampleData/soapToSign.xml
-- Fetch the XML and then sign it..

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

-- This example uses an ECDSA private key for signing.
-- There are many ways to load an ECDSA private key using Chilkat.  This example
-- will load from an unencrypted PEM file.

-- For your convenience, Chilkat put this sample ECDSA PEM here:  https://www.chilkatsoft.com/exampleData/secp256r1-key.zip
local ecKey = chilkat.PrivateKey.new()
success = ecKey:load_pem_file("qa_data/ecc/secp256r1-key.pem")
if not success then
    print(ecKey.last_error_text)
    return
end

-- To create the XML digital signature (i.e. embed the signature within
-- the SOAP XML), we specify what is desired, and then call the method to
-- create the XML signature.
--
-- For example, the application must provide the following:
--     - Where to put the signature.
--     - What to sign.
--     - The algorithms to be used.
--     - The key to be used for signing.
--

local xmlSigGen = chilkat.XmlDSigGen.new()

-- In this example, the Signature will be placed within the wsse:Security element.
-- To specify the location, set the SigLocation property to the XML path to this element,
-- using vertical bar characters to separate tags.
xmlSigGen.sig_location = "SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security"

-- An XML digital signature contains one or more references.  A given reference
-- can be a same-document reference (to an XML fragment), or an external reference.
-- This example will add a single same-document reference.  We'll add a reference to the XML fragment
-- at SOAP-ENV:Body, which is indicated by providing the value of the "Id" attribute (where "Id" is case
-- insensitive).  For each same-document reference, we must also indicate the hash algorithm and XML canonicalization
-- algorithm to be used.  For this example we'll choose SHA-256 and Exclusive XML Canonicalization.
xmlSigGen:add_same_doc_ref("Body", "sha256", "EXCL_C14N", "", "")

-- Let's provide the ECDSA key to be used for signing:
xmlSigGen:set_private_key(ecKey)

-- We're leaving the following properties at their default values:
--
--    - SigNamespacePrefix (default is "ds")
--    - SignedInfoCanonAlg  (default is EXCL_C14N)
--    - SignedInfoDigestMethod (default is sha256)
--    - KeyInfoType (default is "KeyValue", where the ECDSA public key is included in the Signature)

-- Note: Each Reference specifies its own algorithms for XML canonicalization and hashing.
-- The SignedInfo part also has specified hash and canonicalization algorithms, which may be different
-- than the algorithms used in the References.
-- In this example, we use Exclusive XML Canonicalization and SHA-256 throughout.

-- Finally, we're going to set one property that's optional, but commonly used.
-- It's the SignedInfoPrefixList.  In this case, we're using Exclusive Canonicalization, and the signature
-- will be placed in a location within the XML document where namespace prefixes are used in the ancestors.
-- Specifically, the "wsse" and "SOAP-ENV" namespace prefixes are used.
xmlSigGen.signed_info_prefix_list = "wsse SOAP-ENV"

-- OK, everything's specified, so let's create the XML digital signature:
-- This in-place signs the XML.  If successful, sbSoapXml will contain the
-- XML with the digital signature at the specified location.
success = xmlSigGen:create_xml_dsig_sb(sbSoapXml)
if not success then
    print(xmlSigGen.last_error_text)
    return
end

-- Examine the signed SOAP XML:
print(sbSoapXml:get_as_string())

-- This is the signed SOAP XML.
-- Chilkat emits the Signature in compact form on a single line.  Whitespace in XML signatures
-- matters.  Chilkat's opinion is that writing the Signature without whitespace minimizes the chance
-- for problems with whatever software might be verifying the signature.

-- <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
-- <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
--     <SOAP-ENV:Header>
--         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"><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#"><InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV"/></ds:CanonicalizationMethod><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256"/><ds:Reference URI="#Body"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>OwgHPZNfDkXnZsjpfzXqAcT3RV3HzmTsEy2bP44FJ0M=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>jmPSGgtirHSjjcs/o0NIDwwvy4aFBCEosSN+XP5NLVuGpRYnS2EM7mItiw6TKmESAoJYV23ZN4pZ9BFRKSvZqw==</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:Signature></wsse:Security>
--     </SOAP-ENV:Header>
--     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
--         <z:FooBar xmlns:z="http://example.com" />
--     </SOAP-ENV:Body>
-- </SOAP-ENV:Envelope>

-- The above signed XML contains the ECDSA public key in the ECKeyValue fragment (within the ds:KeyInfo).
-- The signature can easily be verified like this:

local verifier = chilkat.XmlDSig.new()

-- First load the XML containing the signature(s) to be verified.
success = verifier:load_signature_sb(sbSoapXml)
if not success then
    print(verifier.last_error_text)
    return
end

local bVerified = verifier:verify_signature(true)
if not bVerified then
    print(verifier.last_error_text)
end

print("Signature verified = " .. tostring(bVerified))