https://github.com/earthstar-project/meadowcap-js

A capability system for Willow.
https://github.com/earthstar-project/meadowcap-js

capabilities p2p willow

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A capability system for Willow.

• Host: GitHub
• URL: https://github.com/earthstar-project/meadowcap-js
• Owner: earthstar-project
• License: lgpl-3.0
• Created: 2023-08-22T06:04:20.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-05-20T13:55:14.000Z (7 months ago)
• Last Synced: 2024-05-23T00:23:07.638Z (7 months ago)
• Topics: capabilities, p2p, willow
• Language: TypeScript
• Homepage: https://willowprotocol.org/specs/meadowcap/index.html#meadowcap
• Size: 416 KB
• Stars: 24
• Watchers: 5
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

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README

        
![](meadowcap.png)

# meadowcap-js

A TypeScript implementation of a capability system for use with the

[Willow protocol](https://willowprotocol.org), according to the

[Meadowcap specification](https://willowprotocol.org/specs/meadowcap).

In Willow, a **namespace** is a self-contained data space with three dimensions:

time, path, and subspace. A namespace's individual _entries_ correspond to

points within this three dimensional space.

_Meadowcap_ enforces boundaries on who gets to read and write what data in a

Willow namespace. Read or write access can be bestowed, delegated to others, or

further restricted within a given three dimensional area.

These boundaries are mediated by _capabilities_. A capability is an unforgeable

token bestowing read or write access for some data to a particular person,

issued by the owner of that data. These capabilities are cryptographically

signed and verified using generic _signature schemes_ (e.g. ed25519) provided by

you.

Meadowcap distinguishes between two types of namespace:

- _Communal namespaces_, where authority is derived from ownership of a given

  _subspace_ key pair. This is a horizontal model where all members of a

  namespace have equal authority, and no-one has authority to all data in the

  namespace.

- _Owned namespace_, where authority is derived from the ownership a given

  _namespace_ keypair. This is a top-down model where the owner of the namespace

  keypair has total control over all data in the namespace, including data

  written by those who have had capabilities delegated to them.

Whether a namespace is communal or not is determined by a function provided by

you. For example, making namespaces communal if their public key ends with a `0`

bit.

Meadowcap will switch between using a (provided) subspace signature scheme or a

namespace signature scheme depending on whether the namespace is communal or

owned, respectively. Most of the time these schemes will be the same, but you

can provide a trivial subspace scheme to effectively deactivate Willow's

subspaces altogether, for example.

This system is meant to be used in tandem with Willow, and **must** be

configured to use many of the same parameters (e.g. namespace signature scheme,

payload digest encoder) as its parent Willow instance. These parameters can be

provided via a `MeadowcapParams` object to construct a `Meadowcap` instance,

which will then give you access to lots of useful methods and hopefully not have

to think about those parameters anymore.

## Usage

This module is published on JSR. See the

[@earthstar/meadowcap page](https://jsr.io/@earthstar) for installation

instructions

Complete API documentation can be found

[here](https://jsr.io/@earthstar/meadowcap/doc).

## Development

Deno is used as the development runtime.

Tests can be run with `deno task test`.

---

This project was funded through the NGI Assure Fund, a fund established by NLnet

with financial support from the European Commission's Next Generation Internet

programme, under the aegis of DG Communications Networks, Content and Technology

under grant agreement № 957073.