Lua Requires Chilkat v9.5.0.66+

JWE using PBES2 Key Wrapping

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create and decrypt a JWE that using PBES2 key wrapping.

This example demonstrates PBES2 with HMAC SHA-256 and A128KW wrapping. It is also possible to do the following by simply changing the "alg" parameter:

• PBES2 with HMAC SHA-384 and A192KW wrapping
• PBES2 with HMAC SHA-512 and A256KW wrapping

Lua

local chilkat = require("chilkat")

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

local plaintext = "Live long and prosper."

local jwe = chilkat.Jwe.new()

-- First build the JWE Protected Header..
local jweProtHdr = chilkat.JsonObject.new()
jweProtHdr:append_string("alg", "PBES2-HS256+A128KW")
jweProtHdr:append_string("enc", "A128GCM")

-- PBES2 requires two additional parameters:
-- 1) A random salt parameter ("p2s") containing 8 or more bytes in base64url format.
-- 2) An iteration count parameter ("p2c").  A minimum count of 1000 is recommended.
--    The iteration count is intended to make the PBES2 computation more expensive (time consuming)
--    to prevent brute-force attacks.
local prng = chilkat.Prng.new()
jweProtHdr:append_string("p2s", prng:gen_random(16, "base64url"))
jweProtHdr:append_string("p2c", "1000")

print("JWE Protected Header: " .. jweProtHdr:emit())
print("--")

-- Don't forget to actually provide the protected header to the JWE object:
jwe:set_protected_header(jweProtHdr)

-- Set the PBES2 password
local recipientIndex = 0
jwe:set_password(recipientIndex, "top secret")

-- Encrypt and return the JWE:
local strJwe = jwe:encrypt(plaintext, "utf-8")
if not jwe.last_method_success then
    print(jwe.last_error_text)
    return
end

-- Show the JWE we just created:
print(strJwe)

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

-- Set the PBES2 password
jwe2:set_password(recipientIndex, "top secret")

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

print("original text: ")
print(originalPlaintext)

-- Sample output:

-- JWE Protected Header: {"alg":"PBES2-HS256+A128KW","enc":"A128GCM","p2s":"z39rTEfRy1T1Yn_D1mZRlg","p2c":"1000"}
-- --
-- eyJhbGciOiJQQkVTMi1IUzI1NitBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIiwicDJzIjoiejM5clRFZlJ5MVQxWW5fRDFtWlJsZyIsInAyYyI6IjEwMDAifQ.koYt6PrFmYwcwdcT7ZcvXHA1d-Xez5h4.luGlbvEnZp-7IsBOj42Yhw.YMTcfLf8Qe4zazozGV2OAu3cUdQ8Kg.rWub47ESWkc6IqZJTvSTmg
-- original text:
-- Live long and prosper.