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Distributed social networks – tools that give you all the social and political benefits of the siloed networks (Google+, Facebook, etc), but without being a massive honey pot for surveillance and data mining, are, in my view, the way we should be heading.

In this model, public posts are easy (that’s just the web), but limiting posts so that they can only be seen by a limited number of your friends is somewhat harder. On Elgg, and similar systems, the standard solution was to make everyone create an account, and profile, on your node. This is, to a large extent, the traditional approach, but basically ends up with you having multiple profiles around the internet (with multiple passwords to remember) which are, crucially, controlled by a third party.

This is a bad thing, and in the post Snowden world, a downright dangerous thing.

I’ve previously discussed a possible approach to providing distributed signon using OpenPGP keys as identity mechanism, and I’ve finally got around to fleshing this out, and building a prototype, now that distributed friending is in Idno/Known core.

Protocol overview

  • Two user profiles, Alice and Bob
  • Alice and Bob generate, or otherwise associate, a PGP key pair with their users (for the most part, only public keys are used in this. You only need to store the private key on the server if you’re automating the process of signing in, and if you can store your private key in your browser, there is eventually no need to store private keys on the server).
  • Alice adds Bob as a friend, and Alice’s site visits Bob’s profile for his public key (see “Public key discovery” below)
  • Rinse, repeat, for Clare, Dave, Emma, Fred, etc…
  • Alice writes a post, and only wants Bob to see it. She lists Bob’s profile URL as an approved viewer.
  • Bob visits the private post, and identifies himself by signing his profile URL with his key, and then POSTing the ascii armoured signature as signature to the post URL.
  • Alice verifies the signature, and confirms that the key’s fingerprint belongs to Bob’s key, and if so, lets Bob see the post.

Public key discovery

Bob makes his public key available by putting it on his web server, and making it easily discoverable to Alice in one or more of the following ways:

  1. Via a HTTP Link header, with a rel of “key”, e.g. Link: https://example.com/bob/pubkey.asc; rel="key"
  2. Via a META tag in the HTTP header, e.g. <meta href="https://example.com/bob/pubkey.asc" />
  3. Via an anchor tag within the page body of rel=”key”, e.g. <a href="https://example.com/bob/pubkey.asc" rel="key">My Key</a>
  4. By pasting the key into the body of the page, and giving it a class of “key”, e.g.

<pre class="key">
-----BEGIN PGP PUBLIC KEY BLOCK-----
....
-----END PGP PUBLIC KEY BLOCK-----
</pre>

Identifying Bob

When Bob wants to see the post that Alice has made, he identifies himself by making a POST request to that page, containing a signed URL of his profile. Alice then verifies the profile URL against those she as allowed access, and verifies that the signature is both correct and that the fingerprint belongs to Bob’s key.

Alice may want to store these access details in a session so she can give Bob access to other resources (logging Bob in, in effect), but this is not strictly necessary.

Other methods are available…

So, why not use OAuth, or signed HTTP requests?

Well first of all, all these authentication methods are not mutually exclusive, so there’s no reason why you can’t use multiple techniques.

Second, we’re using very standard tools (GPG, POST requests, etc), and standard formats, bolted together. Meaning, among other things, although this example (and the Idno implementation) uses a website to do the signing in, this isn’t really required. You can sign in and see a private post, just as easily, using curl and gpg from the command line, if you so require.

Finally, this is entirely distributed, and unlike some implementations of Oauth, or even things like IndieAuth, it requires no central authority to vouch for you. Update:Aaron points out that the latest versions of Indieauth don’t require a central authority.

Idno reference implementation

I have written a plugin that implements this protocol for Idno. In addition to the basic spec, the Idno plugin has the following enhancements, which you may want to consider as well.

Firstly, it uses OpenPGP.js to generate the keypair on the client machine. This preserves server entropy, making it better for hosted environments.

Secondly, the plugin provides you with a bookmarklet, which makes signing in to a compatible site nothing more than a button click.

Please kick both the Idno implementation and the overall spec about, and let me know what you think!

» Visit the project on Github...

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Microformats are an easy way to semantically mark up a web page so that it can be easily parsed and understood by a computer.

This allows you to write code to easily do many funky things, not least of which extract author information from a page with minimal effort. This is how Idno’s distributed friending functionality works, btw.

Idno/Known supports MF2 natively, but support was sadly lacking in Elgg, so I wrote a quick plugin to add it.

Overview

The plugin, once installed and activated, adds some hidden markup to certain core views and does some basic post processing to add MF2 markup.

It is designed to be as light weight as possible, while still providing useful functionality.

As I mentioned above, and in the readme, this was primarily written to scratch an itch – namely, to provide the base functionality for Idno<->Elgg distributed friending functionality. Cross login functionality will come, hopefully, when I have time (although if you’re in a hurry you could always provide an incentive!).

» Visit the project on Github...

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Here is the latest in a series of libraries I’ve been releasing which package up some of my often used, cut and pasted code, into reusable modules for myself and others to use.

So here is the companion piece to my previously released Web Services client library, a web services API endpoint library.

Usage

The library allows you to expose a Callable type (function, object method or static function, closure, and call it via a built in Simple Page Handler endpoint that you can attach to a virtual page (e.g. http://example.com/api).

The library will then use reflection to extract the required and optional parameters, and any default values to pass, and then pass them accordingly.

Once the code has run it’ll trigger an event which you should listen to and determine what format to output the results in based on the 'format' parameter. You might want to look at the Simple Template Library to help you here!

I’ve written an example handler that exposes a single API, but feel free to fire over any comments or questions!

» Visit the project on Github…