kong.jwe

JWE utility module Provides utility functions around JSON Web Encryption.

Decrypt JWE encrypted JWT token and returns its payload as plaintext Supported keys (key argument):

• Supported key formats:
  • JWK (given as a string or table)
  • PEM (given as a string)
  • DER (given as a string)
• Supported key types:
  • RSA
  • EC, supported curves:
    • P-256
    • P-384
    • P-521

Parameters

• key (string|table): Private key
• token (string): JWE encrypted JWT token

Returns

1. string: JWT token payload in plaintext, or nil

2. string: Error message, or nil

Usage

local jwe = require "kong.enterprise_edition.jwe"
local jwk = {
  kty = "EC",
  crv = "P-256",
  use = "enc",
  x   = "MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4",
  y   = "4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM",
  d   = "870MB6gfuTJ4HtUnUvYMyJpr5eUZNP4Bk43bVdj3eAE",
}
local plaintext, err = jwe.decrypt(jwk,
  "eyJhbGciOiJFQ0RILUVTIiwiZW5jIjoiQTI1NkdDTSIsImFwdSI6Ik1lUFhUS2oyWFR1NUktYldUSFI2bXci" ..
  "LCJhcHYiOiJmUHFoa2hfNkdjVFd1SG5YWFZBclVnIiwiZXBrIjp7Imt0eSI6IkVDIiwiY3J2IjoiUC0yNTYi" ..
  "LCJ4IjoiWWd3eF9NVXRLTW9NYUpNZXFhSjZjUFV1Z29oYkVVc0I1NndrRlpYRjVMNCIsInkiOiIxaEYzYzlR" ..
  "VEhELVozam1vYUp2THZwTGJqcVNaSW9KNmd4X2YtUzAtZ21RIn19..4ZrIopIhLi3LeXyE.-Ke4ofA.MI5lT" ..
  "kML5NIa-Twm-92F6Q")
if plaintext then
  print(plaintext) -- outputs "hello"
end

Decode JWE encrypted JWT token and return a table containing its parts This function will return a table that looks like this:

 {
   [1] = protected header (as it appears in token)
   [2] = encrypted key (as it appears in token)
   [3] = initialization vector (as it appears in token)
   [4] = ciphertext (as it appears in token)
   [5] = authentication tag (as it appears in token)
   protected = protected key (base64url decoded and json decoded)
   encrypted_key = encrypted key (base64url decoded)
   iv = initialization vector (base64url decoded)
   ciphertext = ciphertext (base64url decoded)
   tag = authentication tag (base64url decoded)
   aad = protected header (as it appears in token)
 }

The original input can be reconstructed with:

 local token = table.concat(<decoded-table>, ".")

If there is not exactly 5 parts in JWT token, or any decoding fails, the error is returned.

Parameters

• token (string): JWE encrypted JWT token

Returns

1. string: A table containing JWT token parts decoded, or nil

2. string: Error message, or nil

Usage

local jwe = require "kong.enterprise_edition.jwe"
local jwt, err = jwe.decode(
  "eyJhbGciOiJFQ0RILUVTIiwiZW5jIjoiQTI1NkdDTSIsImFwdSI6Ik1lUFhUS2oyWFR1NUktYldUSFI2bXci" ..
  "LCJhcHYiOiJmUHFoa2hfNkdjVFd1SG5YWFZBclVnIiwiZXBrIjp7Imt0eSI6IkVDIiwiY3J2IjoiUC0yNTYi" ..
  "LCJ4IjoiWWd3eF9NVXRLTW9NYUpNZXFhSjZjUFV1Z29oYkVVc0I1NndrRlpYRjVMNCIsInkiOiIxaEYzYzlR" ..
  "VEhELVozam1vYUp2THZwTGJqcVNaSW9KNmd4X2YtUzAtZ21RIn19..4ZrIopIhLi3LeXyE.-Ke4ofA.MI5lT" ..
  "kML5NIa-Twm-92F6Q")
if jwt then
  print(jwt.protected.alg) -- outputs "ECDH-ES"
end

Encrypt plaintext using JWE encryption and returns a JWT token Supported algorithms (alg argument):

• "RSA-OAEP"
• "ECDH-ES"

Supported encryption algorithms (enc argument):

• "A128GCM"
• "A192GCM"
• "A256GCM"
• "A128CBC-HS256"
• "A192CBC-HS384"
• "A256CBC-HS512"

Supported keys (key argument):

• Supported key formats:
  • JWK (given as a string or table)
  • PEM (given as a string)
  • DER (given as a string)
• Supported key types:
  • RSA
  • EC, supported curves:
    • P-256
    • P-384
    • P-521

Supported options (options argument):

• { zip = "DEF" }: whether to deflate the plaintext before encrypting
• { apu = <string|boolean> }: Agreement PartyUInfo header parameter
• { apv = <string|boolean> }: Agreement PartyVInfo header parameter

The apu and apv can also be set to false to prevent them from being auto-generated (sixteen random bytes) and added to ephemeral public key.

Parameters

• alg (string): Algorithm used for key management
• enc (string): Encryption algorithm used for content encryption
• key (string|table): Public key
• plaintext (string): Plaintext
• options (table, optional): Options (optional), default: nil

Returns

1. string: JWE encrypted JWT token, or nil

2. string: Error message, or nil

Usage

local jwe = require "kong.enterprise_edition.jwe"
local jwk = {
  kty = "EC",
  crv = "P-256",
  use = "enc",
  x   = "MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4",
  y   = "4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM",
}
local token, err = jwe.encrypt("ECDH-ES", "A256GCM", jwk, "hello", {
  zip = "DEF,
})
if token then
  print(token)
end