Lua Requires Chilkat v11.0.0+

Generate a CSR with keyUsage, extKeyUsage, and other Extensions

See more CSR Examples

Demonstrates how to generate a CSR containing a 1.2.840.113549.1.9.14 extensionRequest with the following extensions:

• 1.3.6.1.4.1.311.20.2 enrollCerttypeExtension
• 2.5.29.15 keyUsage
• 2.5.29.37 extKeyUsage
• 2.5.29.14 subjectKeyIdentifier

Lua

local chilkat = require("chilkat")

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

-- This example will generate a secp256r1 ECDSA key for the CSR.
local ecc = chilkat.Ecc.new()
local prng = chilkat.Prng.new()
local privKey = chilkat.PrivateKey.new()
local success = ecc:gen_key("secp256r1", prng, privKey)
if not success then
    print("Failed to generate a new ECDSA private key.")
    return
end

local csr = chilkat.Csr.new()

-- Add common CSR fields:
csr.common_name = "mysubdomain.mydomain.com"
csr.country = "GB"
csr.state = "Yorks"
csr.locality = "York"
csr.company = "Internet Widgits Pty Ltd"
csr.email_address = "support@mydomain.com"

-- Add the following 1.2.840.113549.1.9.14 extensionRequest
-- Note: The easiest way to know the content and format of the XML to be added is to examine
-- a pre-existing CSR with the same desired extensionRequest.  You can use Chilkat to
-- get the extensionRequest from an existing CSR.

-- Here is a sample extension request:

-- <?xml version="1.0" encoding="utf-8"?>
-- <set>
--     <sequence>
--         <sequence>
--             <oid>1.3.6.1.4.1.311.20.2</oid>
--             <asnOctets>
--                 <universal tag="30" constructed="0">AEUAbgBkAEUAbgB0AGkAdAB5AEMAbABpAGUAbgB0AEEAdQB0AGgAQwBlAHIAdABpAGYAaQBjAGEAdABl
-- AF8AQwBTAFIAUABhAHMAcwB0AGgAcgBvAHUAZwBoAC8AVgAx</universal>
--             </asnOctets>
--         </sequence>
--         <sequence>
--             <oid>2.5.29.15</oid>
--             <bool>1</bool>
--             <asnOctets>
--                 <bits n="3">A0</bits>
--             </asnOctets>
--         </sequence>
--         <sequence>
--             <oid>2.5.29.37</oid>
--             <asnOctets>
--                 <sequence>
--                     <oid>1.3.6.1.5.5.7.3.3</oid>
--                 </sequence>
--             </asnOctets>
--         </sequence>
--         <sequence>
--             <oid>2.5.29.14</oid>
--             <asnOctets>
--                 <octets>MCzBMQAViXBz8IDt8LsgmJxJ4Xg=</octets>
--             </asnOctets>
--         </sequence>
--     </sequence>
-- </set>

-- Use this online tool to generate code from sample XML:
-- Generate Code to Create XML

-- A few notes:
-- The string "AEUAbgBkAEUAbgB0AGkAdAB5AEMAbABpAGUAbgB0AEEAdQB0AGgAQwBlAHIAdABpAGYAaQBjAGEAdABlAF8AQwBTAFIAUABhAHMAcwB0AGgAcgBvAHUAZwBoAC8AVgAx"
-- is the base64 encoding of the utf-16be byte representation of the string "EndEntityClientAuthCertificate_CSRPassthrough/V1"

local s = "EndEntityClientAuthCertificate_CSRPassthrough/V1"
local bdTemp = chilkat.BinData.new()
bdTemp:append_string(s, "utf-16be")
local s_base64_utf16be = bdTemp:get_encoded("base64")
-- The string should be "AEUA....."
print(s_base64_utf16be)

-- Here's the code to generate the above extension request.

local xml = chilkat.Xml.new()
xml.tag = "set"
xml:update_child_content("sequence|sequence|oid", "1.3.6.1.4.1.311.20.2")
xml:update_attr_at("sequence|sequence|asnOctets|universal", true, "tag", "30")
xml:update_attr_at("sequence|sequence|asnOctets|universal", true, "constructed", "0")
xml:update_child_content("sequence|sequence|asnOctets|universal", s_base64_utf16be)
xml:update_child_content("sequence|sequence[1]|oid", "2.5.29.15")
xml:update_child_content("sequence|sequence[1]|bool", "1")
xml:update_attr_at("sequence|sequence[1]|asnOctets|bits", true, "n", "3")
-- A0 is hex for decimal 160.
xml:update_child_content("sequence|sequence[1]|asnOctets|bits", "A0")
xml:update_child_content("sequence|sequence[2]|oid", "2.5.29.37")
xml:update_child_content("sequence|sequence[2]|asnOctets|sequence|oid", "1.3.6.1.5.5.7.3.3")

-- This is the subjectKeyIdentifier extension.
-- The string "MCzBMQAViXBz8IDt8LsgmJxJ4Xg=" is base64 that decodes to 20 bytes, which is a SHA1 hash.
-- This is simply a hash of the DER of the public key.

local pubKey = chilkat.PublicKey.new()
privKey:to_public_key(pubKey)
local bdPubKeyDer = chilkat.BinData.new()
bdPubKeyDer:append_encoded(pubKey:get_encoded(true, "base64"), "base64")
local ski = bdPubKeyDer:get_hash("sha1", "base64")

xml:update_child_content("sequence|sequence[3]|oid", "2.5.29.14")
xml:update_child_content("sequence|sequence[3]|asnOctets|octets", ski)

-- Add the extension request to the CSR
csr:set_extension_request(xml)

-- Generate the CSR with the extension request
local csrPem = csr:gen_csr_pem(privKey)
if not csr.last_method_success then
    print(csr.last_error_text)
    return
end

print(csrPem)