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(aside: wow my eyes are getting tired from staring at my monitor while I recap of what was a 24 page blogpost, why do I do this to myself)

Aside from being irritated about the name misleading, I don't mind the centralization of did:plc too much (other things, I am more concerned about, we'll get there)

There's one organization that can be queried via their API that keeps a definitive list of certificate and their updates

In theory, once a DID is registered with Bluesky, it cannot be altered by Bluesky, because a cryptographic update from the original key is necessary; it's a certificate chain, a good design

Bluesky can refuse to share did:plc documents or their updates, but it can't manufacture updates

This is pretty good tbh, it lowers the stakes a lot to have certificate chains

I love certificate chains, certificate chains are great

Honestly, having a centralized registry for them, it's not the best but it's not the worst (aside from that damn naming thing)

However...

There are some strange, strange things about did:plc that heightens the centralization concerns and, well

I'm not a cryptographer, but some of my good friends are cryptographers, etc etc. I got some... reactions to what is to follow

The first strange thing to me is that did:plc uses sha256 and, AFAICT, not sha256d (which is really just running sha256 again over the hash). Unless I am missing something? Am I wrong?

Maybe it's not a concern because of doc parsing but it's best practice to protect against length extension attacks

The next concerning thing is that did:plc truncates the hash to just *15 bytes* of entropy.

I'm... again I'm not a cryptographer, but why throw away all that delicious entropy? So the did fits in 32 characters? Weird choice, and it means collisions are cheaper

This is public information, I don't need to file a CVE to tell you about the truncation of entropy. I am, again, not a cryptographer. Maybe it's fine?

I do remember the Debian short IDs fiasco tho https://gwolf.org/2016/06/stop-it-with-those-short-pgp-key-ids.html

Why not hold onto all the entropy you can get?

DIDs weren't meant to be seen by the user; cryptographic identifiers in general *shouldn't be*, they should be encapsulated in the UI.

We'll get to UI stuff in a bit.

I just don't understand this decision though, it just seems weird to me but maybe a cryptographer will tell me it's fine, actually

At any rate, I continue to not understand it, maybe it's fine, but it did play a part in that "Hijacking Bluesky Identities with a Malleable Deputy" blogpost, which is fascinating and, unlike me, is written by a Real Cryptographer (TM) https://www.da.vidbuchanan.co.uk/blog/hacking-bluesky.html

Good post btw

One way in which the truncation shows up in that blogpost which I thought was curious is that the attack involved generating a *longer* truncated hash

The fix ended up resulting in codifying the hash length: 24 characters, and no longer https://github.com/did-method-plc/did-method-plc/pull/31

There's another thing about that blogpost that caught my attention. I will just quote it:

> However, there's one other factor that raises this from "a curiosity" to "a big problem": bsky.social uses the same rotationKeys for every account.

> This is an eyebrow-raising decision on its own; apparently the cloud HSM product they use does billing per key, so it would be prohibitively expensive to give each user their own. (I hear they're planning on transitioning from "cloud" to on-premise hosting, so maybe they'll get the chance to give each user their own keypair then?)

Anyway that's the quote and presumably this must be changed. I haven't looked, but I can't imagine they're still doing this today (are they?) but the fact that only one key was ever used in production for expense purposes is a strange decision

At any rate, that decision was used to create a kinda confused deputy-ish attack, which is why it came up in the blogpost, and anyway, hi, I'm not a cryptographer, momentary reminder that I am not a cryptographer, but I have designed cryptographic certificate chains and I was pretty shocked by that

At any rate, one way or another, you can presumably use did:plc to move yourself from one server to another so in the interest of "credible exit" this is a good choice

Though, one might take a moment to ask: who controls the keys if you *do* want to move?

Bluesky has identified, I'd say correctly even, that key management for users is an *incredibly* hard thing to do.

But the solution, once again, ends up pretty centralized: for all users on Bluesky's main servers at least, Bluesky generates and manages the keys for them.

I am, once again, kinda sympathetic and kinda unsettled simultaneously.

- Sympathetic: key management *is* hard and we just don't have the UX answers to solve that, and Bluesky is once again trying to deliver to Twitter refugees
- Unsettled: it's centralized, but... there's something *more* troubling

The big promise here, the "credible exit" side of things is that for most users, the vision they have is that if Bluesky gets bought by a big evil company, no problem, move somewhere else

But for those same users, Bluesky still *controls their keys* and thus *controls their destiny*

Regardless, Bluesky has this "your domain is your id!" thing, and that's pretty cool, the domain maps to your DID and your DID maps to your domain

Well, I'm not gonna get into this in detail here, I do on the blogpost if you wanna read it but, the cyclic dependency might be an actual cycle

tl;dr on that UX part:

- users only know domains, they don't know the DIDs
- turns out that's a phishing attack when those can change at any time
- if bsky.app ever goes down how do you actually know I *really* mapped to that name
- and a whole lot of "liveness" problems that enter there

in addition to this long-ass thread there is a long-ass article and if you care about things like "zooko's triangle" maybe read that version, the rest of y'all can move on we've got other stuff to cover here

It is time for TEA BREAK 2: THE REHEATENING

I will also go to the bathroom

TMI? If you've read this far into this weird thread I am already giving you too much info

=== TEA BREAK 2 ===

I have returned, with tea

I am still not reading notifications. Well, I have seen a few fly by on the fediverse which is blipping and blooping nonstop in the Mastodon UI so people are clearly reading it there

Bluesky says "30+". How big is the +?? I will resist temptation to look and assume "31"

"Where are we going with this Christine?"

Well you could have just read the blogpost but 3 more sections remain, we are approximately 2/3 there

I know, bear with me, what is left is:

- What should the fediverse do?
- Preparing for the organization as a future adversary
- Conclusions

Yes, I changed the order of the remaining sections, not from the blogpost but from the last time I said what was left on this thread

pray I do not reorder them again

Before we get into the next section, earlier I left an easter egg, which you could reply to and say "I found the easter egg" or something

Now you can put 2 eggs

I 2 was once an egg

(Look I specifically transitioned so I could never be accused of making dad jokes again so that does not qualify)

Alright you've heard enough critiques of Bluesky for a bit and I SAID I was gonna critique the fediverse and I am a WOMAN OF MY WORD

So let's get into it!

I have actually critiqued ActivityPub and the fediverse a lot! I have kind of never stopped critiquing it, ever since the spec was released. There's a lot that can be improved!

I have even gotten criticism from AT LEAST ONE ActivityPub spec author for critiquing AP-as-deployed but I do anyway

Actually something that is funny about ActivityPub is that there's "ActivityPub the spec", which I think is pretty solid for the most part, and "ActivityPub-as-deployed"

Many of the critiques I'm about to lay out we left holes in the spec for which I hoped would be filled with the right answers

One thing we have already discussed so, before I will say anything else, I will repeat: content addressing is really good, and I'd like to see it happen in ActivityPub, and it's *possible to do*, I even wrote a demo of it https://gitlab.com/spritely/golem/blob/master/README.org

Bluesky does the right thing here, AP should too

Content addressing is important. It should not matter where content "lives". It should be able to live anywhere.

A server should be able to go down, and content should survive.

Go content addressing!

Actually with this and several other things I am going to bring up, I actually made sure there was space to do things right: there was a push to make ActivityPub "https-only"

I pushed back on that, I didn't want that requirement, and it was exactly for this reason: enabling content addressing

This isn't the only time I left a critique of ActivityPub-as-Deployed as opposed to ActivityPub-as-it-could-be: see also OCapPub, which critiques the anti-abuse tools of AP as inadequate and leading to "the nation-state'ification of the fediverse" https://gitlab.com/spritely/ocappub/blob/master/README.org

Oh, and ocaps!!!

ActivityPub left giant holes in the spec around two things which sound the same but which are not the same: Authentication and Authorization

Trying to mix these two, you accidentally get ACLs, and then you get confused deputies and ambient authority, plagues of the security world

Anyway, if you know *anything* about me, you know I am a big fan of capability security (ocaps) and that's the foundation of our work over at @spritely

But we will come back to ocaps in a second because it turns out OCapPub is not the only time I proposed AP + ocaps!

The other time I wrote about ActivityPub + ocaps was in a proposal to, yes, Twitter's Bluesky process in 2020 with Jay Graber titled... "ActivityPub + OCaps"! https://gitlab.com/-/snippets/2535398

I think that document laid out all the right ideas for *the fediverse* (not saying bsky, the fediverse)

Now I want to be clear here that I *don't* think that proposal was necessarily the right one for Bluesky, and I *do* think Jay Graber *was* the right person to lead Bluesky

What I wanted to do required a lot more research, and we have done that over at @spritely instead

The reason I bring up the proposal here is that I think it has all the right analysis of *what the fediverse should do*, if it was going to rise to the challenge of fulfilling its true potential

So let me lay out what the things in that proposal were:

Here is your recipe for making the "Correct Fediverse IMO (TM)":

- Integrate ocaps, which is possible because actor model + ocaps compose
- Content addressed storage!
- Decentralized identity (notice the *y*, I did not say DIDs) on top of ~mutable CAS storage
- Petname system UX

(cotd...)

Spec-wise in ActivityPub, I think it's possible. The ecosystem, as deployed? I think the ecosystem can and will only do part of it, if we really get everyone excited, maybe the content addressed storage and decentralized identity parts, in which case the fediverse will also survive nodes going down

The ocap stuff, I tried getting fediverse implementers excited about this and tbh, it's pretty hard to design into a Ruby on Rails or Django style framework and mindset. Backporting the right designs to existing systems is a real challenge.

Especially ocaps need to go bottom-up.

For this reason, @spritely's tech looks like it's very focused on computer science'y low-level BS, but that's actually because it's *too hard to build the systems I want right now on top of current technology*, we need stronger foundations

But people have to build for today too

Let's leave the ocap stuff to the side for now, then. Let's focus on what Bluesky and the fediverse have to learn from each other.

- The fediverse should adopt content-addressed storage and decentralized identity
- Bluesky should adopt real, actual federation and decentralization

For this reason @blaine says of both ActivityPub done right and Bluesky done right, "they're the same picture" (The Office meme goes here, yes)

To a large degree, I think @blaine is right

Of course, adapting an existing system as deployed isn't easy.

I will say though that I think if Bluesky were to become *actually decentralized* it would look a lot like ActivityPub in terms of having directed messaging. This will also introduce similar challenges around eg replies, etc.

To the end of the fediverse, perhaps I sound bitter, "they didn't adopt ActivityPub the way *I* saw it!"

The truth is that Mastodon didn't, but Mastodon also saved ActivityPub. It then painted a vision of the future that wasn't, at least, what Jessica Tallon and I expected of it. But it saved AP.

The fediverse and Bluesky, at great effort, could learn a lot from each other in the immediate term.

In the longer term, neither is implementing the ocap vision I think is critical for the big vision, and in a way, I think maybe neither can be easily rearchitected to achieve it. Well, not yet.

When I laid out the ideas of OCapPub to various fediverse developers, the response was "this sounds cool but I have *no idea* how to retrofit a Rails/Django app for this kind of actor-oriented design".

And they were right.

Remember when I said Conway's Law flows in both directions?

Conway's Law says that a technical architecture reflects the social structure under which it was built. But the reverse is also true. The social structures *we can have* are made possible by the affordances of the tools we have available.

"Tech problems/social problems": false dichotomy.

It's for that reason that @spritely, while aiming for a *socially collaborative* revolution, is first focusing on a *technical* revolution.

It's too hard to build massively, securely collaborative tools right now. With Spritely's tools, p2p ocap secure tech is the *default output*.

Remember when I said that IMO @jay.bsky.team is the right person to lead Bluesky and that I am sympathetic with many design decisions of Bluesky (even if critical of them for being non-decentralized)?

Bluesky is building what they can for a scale big objective. The tech flows from goals.

So too does the social structure flow from the tech. It does on Bluesky, and it does on the fediverse.

I won't elaborate further on this, I actually would like you to pause and think about it. In which ways are tech and social systems bidirectional, here and otherwise? It's important.

The vision laid out for the fediverse, both independently in my writings and even in Jay Graber and I's joint proposal... well, it's a big lift.

@spritely would like to see if we can retrofit our version onto ActivityPub. Time will tell if that's a separate thing.

And perhaps this is all my *massive* Cassandra complex speaking. I won't deny that I have one, for better or worse

Still, despite all I have said about both Bluesky and the fediverse technically, it is because I want a hopeful direction for all of us. Secure collaboration. More important than ever.

Let's take another tea break. (And another bathroom break. This teacup is massive.) We're getting close to done, I promise. Just two sections left, they're both much shorter.

Then I can finally brave reading my notifications.

Maybe.

== TEA BREAK THE THIRD: BEVERAGE TRIFORCE ==

Hello, I am back again. Did you miss me? I still am not reading notifications.

Help I started writing this summary at 11am and it is now 6pm here I have wasted a whole day of work

But I have tea, and I also flossed my teeth, and it is time to resume this thread. If you are here, you know why.

What I am trying to say is I don't have many heroes but @evangreer is absolutely a heroine of mine

You should donate to @fight they are some of the only people doing sensible advocacy against terrible internet laws

Also fuck TERFs

But anyway

Also you have reached it: the third secret egg

You have now collected the egg triforce and can defeat Gender Ganon

If you want to

The power was in you all along

But let's continue.

@fanf42 @soatok It's linked in the blogpost!

@cwebber @soatok :) I confess I didn't read the blog post yet :)