Lua

Create XML Digital Signature using Certificate on Smart Card

See more ScMinidriver Examples

Demonstrates how to load a certificate located on a smart card or USB token and then use it for creating an XML digital signature such that the cryptographic signing happens on the smart card. Lua

local chilkat = require("chilkat")

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

local scmd = chilkat.ScMinidriver.new()

-- Reader names (smart card readers or USB tokens) can be discovered
-- via List Readers or Find Smart Cards
local readerName = "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0"
local success = scmd:acquire_context(readerName)
if not success then
    print(scmd.last_error_text)
    return
end

-- If successful, the name of the currently inserted smart card is available:
print("Card name: " .. scmd.card_name)

-- If desired, perform regular PIN authentication with the smartcard.
-- For more details about smart card PIN authentication, see the Smart Card PIN Authentication Example
local retval = scmd:pin_authenticate("user", "000000")
if retval ~= 0 then
    print("PIN Authentication failed.")
end

-- You can find a cerficate using any of the following certificate parts:
-- "subjectDN" -- The full distinguished name of the cert.
-- "subjectDN_withTags" -- Same as above, but in a format that includes the subject part tags, such as the "CN=" in "CN=something"
-- "subjectCN" -- The common name part (CN) of the certificate's subject.
-- "serial" -- The certificate serial number.
-- "serial:issuerCN" -- The certificate serial number + the issuer's common name, delimited with a colon char.
-- These are the same certificate parts that can be retrieved by listing certificates on the smart card (or USB token).
-- See List Certificates on Smart Card Example
local certPart = "subjectCN"
local partValue = "PIVKey E42D60A759D39147A26E0AF2FB1183C5"

-- If the certificate is found, it is loaded into the cert object.
local cert = chilkat.Cert.new()
success = scmd:find_cert(certPart, partValue, cert)
if not success then
    print("Failed to find the certificate.")
    scmd:delete_context()
    return
end

print("Successfully loaded the cert object from the smart card / USB token.")

-- Note: When successful, the cert object is internally linked to the ScMinidriver object's authenticated session.
-- The cert object can now be used to sign or do other cryptographic operations that occur on the smart card / USB token.
-- If your application calls PinDeauthenticate or DeleteContext, the cert will no longer be able to sign on the smart card
-- because the smart card ScMinidriver session will no longer be authenticated or deleted.

-- ------------------------------------------------------------------------------------------------------------
-- We have the certificate.  Now let's do the XML digital signature..

-- Create the following XML to be signed:

-- <?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>

local xml = chilkat.Xml.new()
xml.tag = "SOAP-ENV:Envelope"
xml:add_attribute("xmlns:SOAP-ENV", "http://schemas.xmlsoap.org/soap/envelope/")
xml:update_attr_at("SOAP-ENV:Header|wsse:Security", true, "xmlns:wsse", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")
xml:update_attr_at("SOAP-ENV:Header|wsse:Security", true, "SOAP-ENV:mustUnderstand", "1")
xml:update_attr_at("SOAP-ENV:Body", true, "xmlns:SOAP-SEC", "http://schemas.xmlsoap.org/soap/security/2000-12")
xml:update_attr_at("SOAP-ENV:Body", true, "SOAP-SEC:id", "Body")
xml:update_attr_at("SOAP-ENV:Body|z:FooBar", true, "xmlns:z", "http://example.com")

-- Prepare for signing...
local gen = chilkat.XmlDSigGen.new()

-- Indicate where the Signature will be inserted.
gen.sig_location = "SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security"

-- Add a reference to the fragment of the XML to be signed.

-- Note: "Body" refers to the XML element having an "id" equal to "Body", where "id" is case insensitive
-- and where any namespace might qualify the attribute.  In this case, the SOAP-ENV:Body fragment is signed
-- NOT because the tag = "Body", but because it has SOAP-SEC:id="Body"
gen:add_same_doc_ref("Body", "sha1", "EXCL_C14N", "", "")

-- (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
gen.signed_info_prefix_list = "wsse SOAP-ENV"

-- Provide the private key for signing via the certificate, and indicate that
-- we want the base64 of the certificate embedded in the KeyInfo.
gen.key_info_type = "X509Data"
gen.x509_type = "Certificate"

-- Note: Our certificate was loaded from the smartcard and is internally linked to the authenticated ScMinidriver session.
-- The signing will occur on the smart card using the chosen certificate.
local bUsePrivateKey = true
success = gen:set_x509_cert(cert, bUsePrivateKey)
if not success then
    print(gen.last_error_text)
    return
end

-- Everything's specified.  Now create and insert the Signature
local sbXml = chilkat.StringBuilder.new()
xml:get_xml_sb(sbXml)
success = gen:create_xml_dsig_sb(sbXml)
if not success then
    print(gen.last_error_text)
    return
end

-- Examine the XML with the digital signature inserted
print(sbXml:get_as_string())

-- ------------------------------------------------------------------------------------------------------------
-- Cleanup our ScMinidriver session...

-- When finished with operations that required authentication, you may if you wish, deauthenticate the session.
success = scmd:pin_deauthenticate("user")
if not success then
    print(scmd.last_error_text)
end

-- Delete the context when finished with the card.
success = scmd:delete_context()
if not success then
    print(scmd.last_error_text)
end