dart_dcaf

An implementation of the ACE-OAuth framework in Dart.

This library implements the ACE-OAuth (Authentication and Authorization for Constrained Environments using the OAuth 2.0 Framework) framework as defined in draft-ietf-ace-oauth-authz-46. Its main feature is CBOR-(de-)serializable data models such as AccessTokenRequest.

Features

• CBOR de-/serializable model of the ACE-OAuth framework:
  • Binary-, text-encoded and AIF-scopes
    • A variant of the AIF format specific to libdcaf is also supported
    • Note that dynamic REST methods in AIF currently don't (de)serialize correctly on the Web platform!
  • Access token requests and responses
  • Authorization server request creation hints
  • Error responses
  • Various smaller types (CoseKey, GrantType, ProofOfPossessionKey, TokenType...)
  • Use serialize() or fromSerialized() to serialize and deserialize these types.

Note that actually transmitting the serialized values (e.g. via CoAP) is out of scope for this library.

Getting started

All you need to do to get started is to add this package to your pubspec.yaml. You can then import it using import 'package:dcaf/dcaf.dart.

Usage

As mentioned, the main feature of this library is ACE-OAuth data models.

For example, say you (the client) want to request an access token from an Authorization Server. For this, you'd need to create an AccessTokenRequest, which has to include at least a clientId. We'll also specify an audience, a scope (using TextScope---note that BinaryScopes or AifScopes would also work), as well as a ProofOfPossessionKey (the key the access token should be bound to) in the reqCnf field.

Creating, serializing and then de-serializing such a structure would look like this:

final request = AccessTokenRequest(
    clientId: "myclient",
    audience: "valve242",
    scope: TextScope("read"),
    reqCnf: KeyId([0xDC, 0xAF]));
final List<int> serialized = request.serialize();
assert(AccessTokenRequest.fromSerialized(serialized) == request);

Its CBOR representation (using CBOR diagnostic notation) would look like this:

{
  "client_id" : "myclient",
  "audience" : "valve424",
  "scope" : "read",
  "req_cnf" : {
    "kid" : h'dcaf'
  }
}

(Note that abbreviations aren't used here, so keep in mind that the labels are really integers instead of strings.)

Additional information

This library is heavily based on dcaf-rs, a similar implementation of the ACE-OAuth framework in Rust, which is intended for all actors in the ACE-OAuth protocol flow (e.g. Authorization Servers too). In contrast, this library is mainly intended for the "Client", hence missing some features present in dcaf-rs. Whenever I update dcaf-rs, I will try to add the new functionality to this library as well (if applicable).

The name DCAF was chosen because eventually, it's planned for this library to support functionality from the Delegated CoAP Authentication and Authorization Framework (DCAF) specified in draft-gerdes-ace-dcaf-authorize (which was specified prior to ACE-OAuth and inspired many design choices in it)---specifically, it's planned to support using a CAM (Client Authorization Manager) instead of just a SAM (Server Authorization Manager), as is done in ACE-OAuth. Compatibility with the existing DCAF implementation in C (which we'll call libdcaf to disambiguate from dcaf referring to this library) is also an additional design goal, though the primary objective is still to support ACE-OAuth.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Maintainers

This project is currently maintained by the following developers:

Name	Email Address	GitHub Username
Falko Galperin	falko1@uni-bremen.de	falko17