Lua Requires Chilkat v11.0.0+

Create a JWS Using ECDSA P-521 SHA-512

See more JSON Web Signatures (JWS) Examples

Creates and verifies a JSON Web Signature (JWS) that uses ECDSA P-521 SHA-512 Lua

local chilkat = require("chilkat")

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

-- Use the following ECC key loaded from JWK format.
local sbJwk = chilkat.StringBuilder.new()
sbJwk:append("{\"kty\":\"EC\",")
sbJwk:append("\"crv\":\"P-521\",")
sbJwk:append("\"x\":\"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk\",")
sbJwk:append("\"y\":\"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2\",")
sbJwk:append("\"d\":\"AY5pb7A0UFiB3RELSD64fTLOSV_jazdF7fLYyuTw8lOfRhWg6Y6rUrPAxerEzgdRhajnu0ferB0d53vM9mE15j2C\"")
sbJwk:append("}")

local eccKey = chilkat.PrivateKey.new()
-- Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
-- into the private key object. (See the online reference documentation..)
local success = eccKey:load_jwk(sbJwk:get_as_string())
if not success then
    print(eccKey.last_error_text)
    return
end

-- Create the JWS Protected Header
local jwsProtHdr = chilkat.JsonObject.new()
jwsProtHdr:append_string("alg", "ES512")

local jws = chilkat.Jws.new()

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

-- Set the ECC key:
jws:set_private_key(signatureIndex, eccKey)

-- 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)

-- Note: ECC signatures use random values, so the output will be different each time a signature is produced.
-- sample output:
-- JWS: eyJhbGciOiJFUzUxMiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.AFOnOtZ8UTp-ed1PfLfXxwGU7zT_jnmGGxew-d1CP6SfKa5RUhav5mF4szhSof22JaoQ742VIa0eZ0s1rhBnj8y6APr6g6vKzIpYZlJsnjzjUwAjDQOLmcsjxrrRfATh-NEv7G0Z9FrjdJasS44tCG2EnG6aT2TW-sPG0dy5o9jUWCzi

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

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

local eccPubKey = chilkat.PublicKey.new()
eccKey:to_public_key(eccPubKey)

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

-- 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 ECC 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()
jws2:get_protected_h(signatureIndex, joseHeader)
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": "ES512"
--     }