Lua Requires Chilkat v11.0.0+

JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

Creates a JSON Web Signatures (JWS) using HMAC SHA-256. Lua

local chilkat = require("chilkat")

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

-- First create the JWS Protected Header
local jwsProtHdr = chilkat.JsonObject.new()
jwsProtHdr:append_string("typ", "JWT")
jwsProtHdr:append_string("alg", "HS256")
print("JWS Protected Header: " .. jwsProtHdr:emit())

-- Output:
-- JWS Protected Header: {"typ":"JWT","alg":"HS256"}

local jws = chilkat.Jws.new()

-- Set the HMAC key:
local hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
local signatureIndex = 0
jws:set_mac_key(signatureIndex, hmacKey, "base64url")

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

-- 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: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

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

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

-- Set the MAC key used for validation.
signatureIndex = 0
jws2:set_mac_key(signatureIndex, hmacKey, "base64url")

-- 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 MAC 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:
--     {
--       "typ": "JWT",
--       "alg": "HS256"
--     }