Lua

JWE using ECDH-ES+A256KW

See more JSON Web Encryption (JWE) Examples

Create a JWE with the following public/private key pair:

{
    "kty": "EC",
    "d": "jZCffzVqJjryBH4EoaN0oD-TyLXrW2XHoDdIuPZnk8c",
    "use": "enc",
    "crv": "P-256",
    "kid": "evEK2thJMsWxBYRivXI8ykUf6n6zizLiLCGH3s58wKs",
    "x": "LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM",
    "y": "voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4",
    "alg": "ECDH-ES+A256KW"
}

Also shows how to decrypt.

Lua

local chilkat = require("chilkat")

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

-- Create the following JSON:
-- {
--     "kty": "EC",
--     "d": "jZCffzVqJjryBH4EoaN0oD-TyLXrW2XHoDdIuPZnk8c",
--     "use": "enc",
--     "crv": "P-256",
--     "kid": "evEK2thJMsWxBYRivXI8ykUf6n6zizLiLCGH3s58wKs",
--     "x": "LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM",
--     "y": "voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4",
--     "alg": "ECDH-ES+A256KW"
-- }

local json = chilkat.JsonObject.new()
json:update_string("kty", "EC")
json:update_string("d", "jZCffzVqJjryBH4EoaN0oD-TyLXrW2XHoDdIuPZnk8c")
json:update_string("use", "enc")
json:update_string("crv", "P-256")
json:update_string("kid", "evEK2thJMsWxBYRivXI8ykUf6n6zizLiLCGH3s58wKs")
json:update_string("x", "LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM")
json:update_string("y", "voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4")
json:update_string("alg", "ECDH-ES+A256KW")

local pubkey = chilkat.PublicKey.new()

local success = pubkey:load_from_string(json:emit())
if not success then
    print(pubkey.last_error_text)
    return
end

-- Build our protected header:

--     {
--       "alg": "ECDH-ES+A256KW",
--       "enc": "A256GCM",
--       "exp": 1621957030,
--       "cty": "NJWT",
--       "epk": {
--         "kty": "EC",
--         "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
--         "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
--         "crv": "BP-256"
--       }
--     }

-- Use jwt only for getting the current date/time + 3600 seconds.
local jwt = chilkat.Jwt.new()

local jweProtHdr = chilkat.JsonObject.new()
jweProtHdr:update_string("alg", "ECDH-ES+A256KW")
jweProtHdr:update_string("enc", "A256GCM")
jweProtHdr:update_int("exp", jwt:gen_numeric_date(3600))
jweProtHdr:update_string("cty", "NJWT")
jweProtHdr:update_string("epk.kty", "EC")
jweProtHdr:update_string("epk.x", "LOakgGvxWBsWbCPLY6Vq6OuBktIqG8POXFXe7ngQ2oM")
jweProtHdr:update_string("epk.y", "voJvS6I-Mc4qqmEA_G2hLQqBck3a3vqaJbmzY7YPUD4")
jweProtHdr:update_string("epk.crv", "P-256")

local jwe = chilkat.Jwe.new()
jwe:set_protected_header(jweProtHdr)
jwe:set_public_key(0, pubkey)

local plainText = "This is the text to be encrypted."
local strJwe = jwe:encrypt(plainText, "utf-8")
if not jwe.last_method_success then
    print(jwe.last_error_text)
    return
end

print(strJwe)

-- Let's decrypt...
local privkey = chilkat.PrivateKey.new()

success = privkey:load_jwk(json:emit())
if not success then
    print(privkey.last_error_text)
    return
end

local jwe2 = chilkat.Jwe.new()
success = jwe2:load_jwe(strJwe)
if not success then
    print(jwe2.last_error_text)
    return
end

jwe2:set_private_key(0, privkey)

--  Decrypt.
local decryptedText = jwe2:decrypt(0, "utf-8")
if not jwe2.last_method_success then
    print(jwe2.last_error_text)
    return
end

print(decryptedText)