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Bridgefy, the messenger promoted for mass protests, is a privacy disaster

arstechnica.com

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Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#41

Post by wyuenho »

eindiran wrote: post #4

I have noticed that since the protests began there has been a huge influx of my contacts onto Signal and I've gotten a few questions about how to use PGP. I'm glad folks are starting to take privacy in their messengers more seriously, but a lot of the privacy-focused messengers are pretty bad (with Bridgefy being a particularly egregious case). Unfortunately there seems to be a trade off continuum between user friend…

Signal's disappearing messages will appear on your other devices such as the desktop app long after disappearing on the phone, and you still get group message asking if you'd like to join back the group you just left. Imagine these messages popping up right at the moment during police interrogation.

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#42

Post by [deleted] »

Multicomp wrote: post #7
eindiran wrote: post #4

I have noticed that since the protests began there has been a huge influx of my contacts onto Signal and I've gotten a few questions about how to use PGP. I'm glad folks are starting to take privacy in their messengers more seriously, but a lot of the privacy-focused messengers are pretty bad (with Bridgefy being a particularly egregious case). Unfortunately there seems to be a trade off continuum between user friend…

My money is on p2p matrix. It doesn't solve the immediate case Bridgefy does yet (I think it expects to have an internet connection), but it does solve the 'we have to trust central services like signal and or have incredibly difficult ux' scenario somewhat. Metadata resistant to a point etc. Cwtch.im (pronounced couch) is an app I'm looking closely at but doesn't seem to have much movement in terms of shipping new r…

[deleted]

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#43

Post by upofadown »

tialaramex wrote: post #20
upofadown wrote: post #18

>A key shortcoming that makes many of these attacks possible is that Bridgefy offers no means of cryptographic authentication, which one person uses to prove she’s who she claims to be. Identity is critical in encrypted messaging. Identity is a hard problem in practice. Very few things do an adequate job. The things that do are awkward and require concepts that few people understand.

Somebody needs to expend a bunch of effort to provide identity. It doesn't have to be you (in a PKI the effort is expended by the Certificate Authorities and those overseeing them, not by Relying Parties) but it does have to be somebody you trust. For personal identity the most plausible outside authority is government, and it's unlikely that people protesting a government would trust it to identify them - after all…

No one really wants their legal identity linked to a messaging identity anyway. It just isn't a suitable concept. Identity in a messaging context normally has multiple instances. You don't want your work identity linked to your family identity linked to your bar identity...

Leaving off the question of how useful the transitive stuff is, PGP has a reasonable and simple framework. The terminology of key trust is terrible though. Few people know what it means to trust a key (my house key is OK but I think my shed key might be up to no good).

Messaging identity reputation is all about what you think of the other people's identities. Do you know them? What context do you know them from (e.g. a particular protest)? Why you think this messaging identity relates to a person somehow? How is this entity allowed to interact with you? This stuff can't be automated away.

I think the ultimate answer would have to involve generating a simple conceptual model of a messaging identity and then teaching people about it. If you solve identity then everything else is easy.

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#44

Post by rtkwe »

namibj wrote: post #22
rtkwe wrote: post #15

Does anyone have a design that works for this kind of adhoc meshing network with good privacy guarantees? It seems like a really hard problem to solve, especially the social graph problem because inherently messages will take time to propagate through the network based on proximity. Maybe adding random wait and hop count increments? Efficient routing kind of depends on being able to discover the network graph.

Briar works quite well, but due to the darknet nature you only exchange data with those you paired with (by exchanging a "link" via some other channel or meeting in-person and scanning a QR code on each other's device (then followed by a short wireless p2p exchange to properly exchange all required information)). It's afaik android-only, and doesn't use nodes as relays for private messages.

That sounds like it only solves the very narrow issue of private messages and only while the two users are within direct communication right?

That seems like a relatively easy corner to deal with. What I really want to see is one with meshing, public chats, and open joining (of the public chats, verifying contact names can be done offline). That’s where it starts to be actually useful in protest etc situations where public internet access might not be available.

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#45

Post by vkou »

slg wrote: post #12
vkou wrote: post #11

Earlier quoted context omitted.

You can always ask for a refund of the zero dollar purchase price. :/

Do you think a company has zero obligations to its users if those users are not paying for the service? Most of us have never directly paid Google for anything. I think we would still have justification in being upset if there was a central Google flaw that allowed users to view our search or Gmail histories.

Ethical obligation? Sure. Ethics don't put bread on the table, though. Practical obligation? You get what you pay for.

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#46

Post by nordsieck »

faeyanpiraat wrote: post #34
nordsieck wrote: post #24

Earlier quoted context omitted.

> Doesn't that qualify as some sort of fraud or false advertising? Fraud typically requires some sort of mens rea. It sounds to me like Bridgefy is just really bad as making secure applications. > If not, I wonder if we need further regulation to protect the public from developers that are either incompetent or straight malicious. There is a long history of people trying to create liability for software bugs. It was…

Why? If a bridge is built wrong and kills people when it collapses, someone must be at fault. What’s the difference if it happens with a virtual “thing”?

> Why?

> If a bridge is built wrong and kills people when it collapses, someone must be at fault.

1. We mostly know how to build bridges that don't collapse. We do not know how to create software that doesn't contain bugs. Even with the most intense scrutiny.

2. Software exists along a gradient between casual to critical, whereas all structural/civil engineering is of critical importance. It simply makes no sense for society to force you to analyze your Excel formulas as intensely as a civil engineer analyzes a bridge.

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#47

Post by jorgeribs »

Hi everyone, I'm Jorge, founder at Bridgefy.

We're acutely aware of this conversation, and know that we must prioritize the safety of our user base. All of the issues reported on the article are already being fixed, and we should have updates published in the next few weeks.

Here's our blog post: https://bridgefy.me/bridgefys-commitment-to-privacy-and-secu...

As always, we're available to keep the conversation going; please refer to the email address included in the blog post.

Thanks!

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#48

Post by Reelin »

rrdharan wrote: post #40
Reelin wrote: post #29

Earlier quoted context omitted.

> But trust isn't transitive so PGP's apparently more powerful offering doesn't actually do anything ... Trust in the abstract isn't inherently transitive, agreed. I'd argue that employing PGP as though it were is misusing the tool (that might well be easier to do than it ought to be, but that's a different conversation). WoT as realized by PGP seems to me to be a very good tool for manually assessing whether to trus…

> WoT as realized by PGP seems to me to be a very good tool for manually assessing whether to trust a previously unknown key for someone that a third (untrusted) party sends you. https://inversegravity.net/2019/web-of-trust-dead/

That article isn't particularly relevant to what I said.

The issues it describes only affect keyservers that behave in a specific manner. I'd also argue that a keyserver behaving that way in the first place is fundamentally flawed for the reason pointed out by @tialaramex above - trust isn't transitive in the generalized case (nor is it boolean IMO).

It is still entirely possible for a small group (say a FOSS software project) to engage in cross signing. Previously unseen keys received from an untrusted (or less trusted) third party can then be judged on a case by case basis by manually assessing how many times they have been signed and by which keys.

(Similar to above, I believe Matrix employs cross signing among the keys of a single user.)

Re: Bridgefy, the messenger promoted for mass protests, is a privacy disaster

#49

Post by namibj »

rtkwe wrote: post #44
namibj wrote: post #22

Earlier quoted context omitted.

Briar works quite well, but due to the darknet nature you only exchange data with those you paired with (by exchanging a "link" via some other channel or meeting in-person and scanning a QR code on each other's device (then followed by a short wireless p2p exchange to properly exchange all required information)). It's afaik android-only, and doesn't use nodes as relays for private messages.

That sounds like it only solves the very narrow issue of private messages and only while the two users are within direct communication right? That seems like a relatively easy corner to deal with. What I really want to see is one with meshing, public chats, and open joining (of the public chats, verifying contact names can be done offline). That’s where it starts to be actually useful in protest etc situations where…

It also supports two kinds of group chats and contact introductions.

Forums allow any member to invite anyone in their contact list.

Group chats have an admin who can invite anyone in their contact list, and also forcibly kick members out of the group.

Forums show a HN-like threaded view, and afaik group chats show a linear history.

Group/Forum message sharing is done between peered contacts whenever they get connected (either locally by being in the same WLAN/in blutooth range, or remove via a tor hidden service).

It currently lacks the requested open joining, though this can be emulated by using a "Forum" and the spam issue there could be handled by adding UI to see who gossip'd you a certain message (which you deem to be spam), so that you can have a word with this contact. Temporarily stopping incoming gossiping from a peer for specific forums might also be needed to scale to "huge" forums without having a massive spam problem, as you don't (necessarily) want to remove them from your contact list without giving them a chance to block the source of spam they had, as they'd perceive your removal of them from your list as you never going online again.

Joining is very simple, so you could probably just approach a few people at the protest about whether they have Briar, and if so, whether they'd pair with you to share the current protests forum.

It also has a "blog" functionality where there's a history of your "current status", and you could, if you wanted to, tell your peers about going to a new protest or so and that they should both ask you for a forum invite for the protest, and send you an invite if they get into a forum for this protest.

It shouldn't require many links to get reasonable message relaying across a relatively dense protest, especially considering that sneakernet aspects are essentially automatic.

I think with some more manpower they could quite soon have a system that's highly resilient to spam (provenance visualization/blocking), blackout-capable, and privacy-preserving/secure for non-public groups/forums.

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