Lua Requires Chilkat v11.5.0+

Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card. Lua

local chilkat = require("chilkat")

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

-- Load the certificate from a smart card.
local cert = chilkat.Cert.new()

-- Set the smarcard PIN prior to loading
cert.smart_card_pin = "123456"

-- Detect the connected smartcard or USB security token and load the default certificate.
local success = cert:load_from_smartcard("")
if not success then
    print(cert.last_error_text)
    return
end

-- Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
-- such as selecting a certificate if the card contains multiple certificates with private keys,
-- or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

-- Create the JWS Protected Header
local jwsProtHdr = chilkat.JsonObject.new()

if cert:is_ecdsa() then
    jwsProtHdr:append_string("alg", "ES256")
else
    jwsProtHdr:append_string("alg", "RS256")
end

local jws = chilkat.Jws.new()

-- Set the protected header:
local signatureIndex = 0
jws:set_protected_header(signatureIndex, jwsProtHdr)

-- Provide the private key via the certificate.
jws:set_signing_cert(signatureIndex, cert)

-- Set the payload.
local bIncludeBom = false
local payloadStr = "In our village, folks say God crumbles up the old moon into stars."
jws:set_payload(payloadStr, "utf-8", bIncludeBom)

-- Create the JWS
-- By default, the compact serialization is used.
local jwsCompact = jws:create_jws()
if not jws.last_method_success then
    print(jws.last_error_text)
    return
end

print("JWS: " .. jwsCompact)

-- sample output:
-- JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

-- Now load the JWS, validate, and recover the original text.
local jws2 = chilkat.Jws.new()

-- Load the JWS.
success = jws2:load_jws(jwsCompact)

local pubKey = chilkat.PublicKey.new()
cert:get_public_key(pubKey)

-- Set the public key used for validation.
signatureIndex = 0
jws2:set_public_key(signatureIndex, pubKey)

-- Validate the 1st (and only) signature at index 0..
local v = jws2:validate(signatureIndex)
if v < 0 then
    -- Perhaps Chilkat was not unlocked or the trial expired..
    print("Method call failed for some other reason.")
    print(jws2.last_error_text)
    return
end

if v == 0 then
    print("Invalid signature.  The key was incorrect, the JWS was invalid, or both.")
    return
end

-- If we get here, the signature was validated..
print("Signature validated.")

-- Recover the original content:
print(jws2:get_payload("utf-8"))

-- Examine the protected header:

local joseHeader = chilkat.JsonObject.new()
success = jws2:get_protected_h(signatureIndex, joseHeader)
if not success then
    print(jws2.last_error_text)
    return
end

joseHeader.emit_compact = false

print("Protected (JOSE) header:")
print(joseHeader:emit())

-- Output:

--     Signature validated.
--     In our village, folks say God crumbles up the old moon into stars.
--     Protected (JOSE) header:
--     {
--       "alg": "RS256"
--     }