Iron, Hawk, Oz: Web auth protocols https://github.com/rvl/hsoz

Latest on Hackage:

This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow stackage.org to host generated Haddocks.

BSD3 licensed by Rodney Lorrimar
Maintained by Rodney Lorrimar

Oz Haskell Implementation

Build Status Hackage

hsoz is a Haskell implementation of the Iron, Hawk, and Oz web authentication protocols. These protocols originate from the OAuth2 standardisation process, but are designed to be simpler to implement for the common case of web applications.


In the words of their principal designer:

Iron is a cryptographic utility for sealing a JSON object using symmetric key encryption with message integrity verification. Or in other words, it lets you encrypt an object, send it around (in cookies, authentication credentials, etc.), then receive it back and decrypt it. The algorithm ensures that the message was not tampered with, and also provides a simple mechanism for password rotation.

Hawk is an HTTP authentication scheme using a message authentication code (MAC) algorithm to provide partial HTTP request cryptographic verification.

Oz is a web authorization protocol based on industry best practices. Oz combines the Hawk authentication protocol with the Iron encryption protocol to provide a simple to use and secure solution for granting and authenticating third-party access to an API on behalf of a user or an application.


The Haddock documentation is on Hackage and at https://rodney.id.au/docs/hsoz/.

Example Usage

See the Network.Iron documentation, and the example directory of this repository.


This is an in-progress experiment in implementing the protocol in Haskell.

  • Iron: complete
  • Hawk: complete
  • Oz: under construction.
  • Example web application: under construction.

Please note: until the example application is built, this library cannot be considered "battle-tested".

There is also an org-mode file: todo.org.


I welcome collaborators, particularly anyone who would like to develop authentication plugins for frameworks such as Snap and Servant, or a manager for Wreq.

Building with Stack

stack build

Building with Nix

nix-shell -p cabal2nix --command "cabal2nix --shell . > default.nix"
nix-shell --command "cabal configure"
cabal build


This module is based on the Javascript code and documentation by Eran Hammer and others. A fair amount of Hammer's descriptive text has been incorporated into this documentation, as well as the cool logos.

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