Lua Requires Chilkat v9.5.0.90+

CMS Sign Hash

Demonstrates how to use the SignHashENC method to sign a pre-computed hash. This method creates a CMS signature (PKCS7 detached signature). Lua

local chilkat = require("chilkat")

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

local crypt = chilkat.Crypt2.new()

-- Create the hash to be signed...
crypt.hash_algorithm = "sha256"
crypt.encoding_mode = "base64"
crypt.charset = "utf-8"
-- Create the SHA256 hash of a string using the utf-8 byte representation.
-- Return the hash as base64.
local base64Hash = crypt:hash_string_enc("This is the string to be hashed")

-- Load a certificate for signing.
local cert = chilkat.Cert.new()
local success = cert:load_pfx_file("qa_data/pfx/cert_test123.pfx", "test123")
if not success then
    print(cert.last_error_text)
    return
end

crypt:set_signing_cert(cert)

-- Sign the hash to create a base64 CMS signature (which does not contain the original data).
-- We can get the signature in a single line of base64 by specifying "base64", or
-- we can get multi-line base64 by specifying "base64_mime".
crypt.encoding_mode = "base64_mime"
local base64CmsSig = crypt:sign_hash_enc(base64Hash, "sha256", "base64")
if not crypt.last_method_success then
    print(crypt.last_error_text)
    return
end

-- Note: In the above call to SignHashENC, the encoding of the returned CMS signature is specified by the EncodingMode property.
-- However, the encoding of the passed-in hash is indicated by the 3rd argument.

print("CMS Signature: " .. base64CmsSig)