Lua Requires Chilkat v9.5.0.69+

Create XML Signature with External Data Reference

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature where the data is external. In this case, the data is a JPG file. Lua

local chilkat = require("chilkat")

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

-- This example inserts an XML signature in the following XML:

-- <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-- <abc>
--   <xyz>
--     <jpg>
--         <name>starfish.jpg</name>
--         <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
--     </jpg>
--   </xyz>
-- </abc>

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

local url = "https://www.chilkatsoft.com/exampleData/addSignatureToThis.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

-- We'll use an RSA private key for signing.
local rsaKey = chilkat.PrivateKey.new()
success = rsaKey:load_pem_file("qa_data/rsa/rsaPrivKey_pkcs8.pem")
if not success then
    print(rsaKey.last_error_text)
    return
end

local xmlSigGen = chilkat.XmlDSigGen.new()

-- Indicate were the Signature will be inserted:
xmlSigGen.sig_location = "abc|xyz|jpg"

-- Provide the RSA key to be used for signing:
xmlSigGen:set_private_key(rsaKey)

-- Fetch the JPG image data.
local jpgUrl = "https://www.chilkatsoft.com/images/starfish.jpg"
local jpgData = chilkat.BinData.new()
success = http:quick_get_bd(jpgUrl, jpgData)
if not success then
    print(http.last_error_text)
    return
end

-- Add the external data reference:
xmlSigGen:add_external_binary_ref(jpgUrl, jpgData, "sha256", "")

-- Create the XML digital signature:
success = xmlSigGen:create_xml_dsig_sb(sbXml)
if not success then
    print(xmlSigGen.last_error_text)
    return
end

-- Examine the XML that now contains the Signature:
print(sbXml:get_as_string())

-- <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-- <abc>
--   <xyz>
--     <jpg>
--         <name>starfish.jpg</name>
--         <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
--     <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#rsa-sha256"/><ds:Reference URI="https://www.chilkatsoft.com/images/starfish.jpg"><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>AOU810yJV5Np/DnO29qpObqiTSTTCDvxGsX5ayiTYXI=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>ApHRr6nilNrzt3dLveC9zlPoSllaCMfHsbAwr+vYBPkHkJ4wD5LzDDhi1tSJZAAeTckmvSqIG3Wi0rgXQiSM644MD3coBFx4QgrY+GZ+XJJE2Y0Ye3VvaQBiRdUW3INGsW4GLubncgQk5JhuAQjo6O/GKpfEuYqUJj/6CLHLQwMPwbZ2043ykgzuPFoOZf6EydJMBAn1ORMvrpUn+zuA9UngOTGap6eWE4CeiNx23BRC2wSztbUjdCLcqXvgiYu/v0tBNaTcwy7b6+IFtwv/lNUUBUQJ/3p+aErzFn3wLeH3yeqpDCU0U6Dqu5SS1jYupcWWsLHJjYnj2066DPJi/g==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:RSAKeyValue><ds:Modulus>sXeRhM55P13FbpNcXAMR3olbw2Wa6keZIHu5YTZYUBTlYWId+pNiwUz3zFIEo+0IfYR0H27ybIycQO+1IIzJofUFNMAL3tZps2OKPlsjuCPls6kXpXhv/gvhux8LrCtp4PcKWqJ6QVOZKChc7WAx40qFWzHi57ueqRTv3x0kESqGg/VjsqyTEvb55psJO2RsfhLT7+YVh3hImRM3RDaJdkTkPuOxeFyT6N7VXD09329sLuS3QkUbE9zEKDnz9X3d8dEQdJhSI9ba5fxl8R7fu8pB67ElfzFml96X1jLFtzy1pzOT5Fc4ROcaqlYckVzdBq9sxezm6MYmDBjNAcibRw==</ds:Modulus><ds:Exponent>AQAB</ds:Exponent></ds:RSAKeyValue></ds:KeyValue></ds:KeyInfo></ds:Signature></jpg>
--   </xyz>
-- </abc>
--