JWT Signed Request

Request signing and verification for Internal APIs using JWT.

Getting Started

Add this line to your application's Gemfile:

gem 'jwt_signed_request'

then run:

$ bundle

Generating EC Keys

We should be using a public key encryption algorithm such as ES256. To generate your public/private key pair using ES256 run:

$ openssl ecparam -genkey -name prime256v1 -noout -out myprivatekey.pem
$ openssl ec -in myprivatekey.pem -pubout -out mypubkey.pem

Store and encrypt these in your application secrets.

Configuration

You can add signing and verification keys to one or more key stores as your application needs them.

For example, given the following keys:

private_key = <<-PEM.gsub(/^\s+/, "")
    -----BEGIN EC PRIVATE KEY-----
    MHcCAQEEIBOQ3YIILYMV1glTKbF9oeZWzHe3SNQjAx4IbPIxNygQoAoGCCqGSM49
    AwEHoUQDQgAEuOC3ufTTnW0hVmCPNERb4LxaDE/OexDdlmXEjHYaixzYIduluGXd
    3cjg4H2gjqsY/NCpJ9nM8/AAINSrq+qPuA==
    -----END EC PRIVATE KEY-----
  PEM

public_key = <<-PEM.gsub(/^\s+/, "")
  -----BEGIN PUBLIC KEY-----
  MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEuOC3ufTTnW0hVmCPNERb4LxaDE/O
  exDdlmXEjHYaixzYIduluGXd3cjg4H2gjqsY/NCpJ9nM8/AAINSrq+qPuA==
  -----END PUBLIC KEY-----
PEM

Single key store

If your application only needs a single key store, configure it like so:

require 'openssl'

JWTSignedRequest.configure_keys do |config|
  config.add_signing_key(
    key_id: 'client_a',
    key: OpenSSL::PKey::EC.new(private_key),
    algorithm: 'ES256',
  )

  config.add_verification_key(
    key_id: 'client_a',
    key: OpenSSL::PKey::EC.new(public_key),
    algorithm: 'ES256',
  )
end

Multiple key stores

If your application requires multiple key stores, configure them like so:

key_store_id = 'widget_admin'

JWTSignedRequest.configure_keys(key_store_id) do |config|
  config.add_signing_key(
    key_id: 'client_a',
    key: OpenSSL::PKey::EC.new(private_key),
    algorithm: 'ES256',
  )

  config.add_verification_key(
    key_id: 'client_a',
    key: OpenSSL::PKey::EC.new(public_key),
    algorithm: 'ES256',
  )
end

Signing Requests

If you have added your signing keys to a key store, you will only need to specify the key_id you are signing the requests with.

If you are using multiple key stores, you will also need to pass the appropriate key_store_id.

Using net/http

require 'net/http'
require 'uri'
require 'openssl'
require 'jwt_signed_request'

uri = URI('http://example.com')
req = Net::HTTP::Get.new(uri)
jwt_token = JWTSignedRequest.sign(
  method: req.method,
  path: req.path,
  headers: {"Content-Type" => "application/json"},
  body: "",
  key_id: 'my-key-id',                    # used for looking up key and kid header
  lookup_key_id: 'my-alt-key-id',         # optionally override lookup key
  key_store_id: 'widget_admin',           # optionally specify named key store ID
  issuer: 'my-issuer'                     # optional
  additional_headers_to_sign: ['X-AUTH']  # optional
)

req['Authorization'] = "Bearer #{jwt_token}"

res = Net::HTTP.start(uri.hostname, uri.port) {|http|
  http.request(req)
}

Using Faraday

require 'faraday'
require 'openssl'
require 'jwt_signed_request/middlewares/faraday'

conn = Faraday.new(url: URI.parse('http://example.com')) do |faraday|
  faraday.use(
    JWTSignedRequest::Middlewares::Faraday,
      key_id: 'my-key-id',
      key_store_id: 'my-key-store-id',        # optional
      issuer: 'my-issuer',                    # optional
      additional_headers_to_sign: ['X-AUTH'], # optional
      bearer_schema: true,                    # optional
    )

  faraday.adapter Faraday.default_adapter
end

conn.post do |req|
  req.url 'http://example.com'
  req.body = '{ "name": "Unagi" }'
end

Additional options

bearer_schema (boolean)

Determines whether to use the Bearer schema when assigning the JWT token to the Authorization request header

bearer_schema value	Authorization header value
false (default)	<jwt_token>
true	Bearer <jwt_token>

Verifying Requests

Please make sure you have added your verification keys to the appropriate key store. Doing so will allow the server to verify requests signed by different signing keys.

Using Rails

class APIController < ApplicationController
  before_action :verify_request

  ...

  private

  def verify_request
    begin
      JWTSignedRequest.verify(
        request: request,
        # Use optional `key_store_id` kwarg when working with multiple key stores, eg:
        key_store_id: 'widget_admin',
      )

    rescue JWTSignedRequest::UnauthorizedRequestError => e
      render :json => {}, :status => :unauthorized
    end
  end

end

Increasing Expiry leeway

JWT tokens contain an expiry timestamp. If communication delays are large (or system clocks are sufficiently out of synch), you may need to increase the 'leeway' when verifying. For example:

  JWTSignedRequest.verify(request: request, leeway: 55)

Using Rack Middleware

class Server < Sinatra::Base
  use(
    JWTSignedRequest::Middlewares::Rack,
    exclude_paths: /public|health/,          # optional regex
    leeway: 100,                             # optional
    key_store_id: 'my-key-store-id',         # optional
  )
 end

Backwards Compability

Please note that the way we sign and verify requests has changed in version 2.x.x. For documentation on how to use older versions please look here.

We are only supporting the old API for the next couple of releases of version 2.x.x so please upgrade ASAP.

Maintainers

• Envato

License

JWTSignedRequest uses MIT license. See LICENSE.txt for details.

Code of conduct

We welcome contribution from everyone. Read more about it in CODE_OF_CONDUCT.md

Contributors

Many thanks to the following contributors to this gem:

• Toan Nguyen - @yoshdog
• Odin Dutton - @twe4ked
• Sebastian von Conrad - @vonconrad
• Zubin Henner- @zubin
• Glenn Tweedie - @nocache
• Giancarlo Salamanca - @salamagd
• Ben Axnick - @bentheax
• Glen Stampoultzis - @gstamp
• Lucas Parry - @lparry
• Chris Mckenzie - @chrisface

Contributing

For bug fixes, documentation changes, and small features:

1. Fork it ( https://github.com/envato/jwt_signed_request/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

For larger new features: Do everything as above, but first also make contact with the project maintainers to be sure your change fits with the project direction and you won't be wasting effort going in the wrong direction

Compatibility

Compatibility with multiple versions of the JWT gem is tested via the appraisal gem.

Configured versions are defined in Appraisals, which at time of writing looked like this:

# Latest JWT minor versions
# Source: https://rubygems.org/gems/jwt/versions
%w[
  1.5.6
  2.0.0
  2.1.0
  2.2.1
].each do |jwt_version|

Run the test suite like this:

# Test all configured versions
bundle exec appraisal rspec

# Target a specific configured version
bundle exec appraisal jwt-1.5.6 rspec