Comment on Pixelfed leaks private posts from other Fediverse instances - fiona fokus
Irelephant@lemm.ee 4 weeks agoNo, Imagine this
There is @bob@pixelfed.example their is their friend, @joe@mastodon.example. bob also follows @jane@gotosocial.example
If bob makes a private post (ie, followers only), only the instances of people he follows will recieve the post. The instance will see that its supposed to be private, and not show it to everyone.
This may, gotosocial.example, mastodon.example and pixelfed.example have the post, but don’t show it. misskey.example won’t have the post.
Then, if gotosocial.example (hypothetically) had a bug where it ignored posts visibility settings, those posts would be shown, since the post is sent to that server. If misskey.example had a similar bug, nothing would happen as the post wouldn’t have reached that server anyway.
PhilipTheBucket@ponder.cat 4 weeks ago
Yeah, so there’s no real way to implement private posts on Mastodon.
I mean, it is fine if you want to implement sort of “best effort” semi-privacy and make it clear to everyone involved that that’s what it is, but for any reasonable definition of “private,” the requirement that it not get shown to people outside the list of people allowed to see it needs to be enforced better than this. There will always be server software that doesn’t “cooperate.” That’s just the nature of open distributed systems. If you’re making assurances to your users that their posts will be private, you need to be the one enforcing that, not everyone else on the network and the protocol needs to be set up with the ability for that to happen (which ActivityPub is not, which means it’s misleading that someone told users that they can have “private” posts via this hack.)
Irelephant@lemm.ee 4 weeks ago
I wouldn’t consider it a hack, as the protocol was actually made with these posts in mind. Public posts weren’t the focus of activitypub.
I would consider it similar to email, should we abandon it (yes, but not because of this) just because a malicious email server started publishing all the emails it recieved? AP is just email but social media.
PhilipTheBucket@ponder.cat 4 weeks ago
Yes, and people implemented PGP for encrypted email, and also made SMTP over TLS the standard, so that they wouldn’t have to demand that every router and every SMTP server everywhere on the internet agree not to republish or store secret information that was passing through it, because it started to become understood that email was in no way private.
A proper standard for private posts would be similar. You could have all private posts be encrypted with a rotating key, for example, and have them decrypted by anyone who had the key, on the client side, and stored and transmitted in encrypted form. Being approved to follow the private posts would involve your user being given a copy of the key through some kind of private key exchange. It sounds complex (and it would be, a little), and it would involve moving to the client some of the key management that currently happens on the instance server (and thus undoes some of the actually good design of ActivityPub, by just putting the instance software back in the position of keeping every actor’s keys for them and doing all the crypto work on behalf of the users). Anyway, it would be work and involve some redesign. I’m not saying that’s what they should have done. I’m saying that’s what having private posts as a feature would mean. Anything else is non-private posts that are pretending to be private posts.
Irelephant@lemm.ee 4 weeks ago
Posts should be encrypted, this is what diaspora does. I agree with this. For emails though, pgp is used by no-one. Also, AP uses tls as well.
I was thinking that encrypted posts could work with multi key encryption (if my understanding of this post is correct stackoverflow.com/…/encryption-decryption-with-mu… ).
The problem (imo) is mastodon being the internet explorer of the fediverse, and refusing to do any encryption.
iltg@sh.itjust.works 4 weeks ago
email works the same way. it’s impossible to implement private emails? if you cc your email to im.going.to@leak.it and it leaks, would it be fair to complain about the whole email system?
PhilipTheBucket@ponder.cat 4 weeks ago
discuss.privacyguides.net/t/…/20662