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Technology preview: Private contact discovery for Signal

signal.org

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Re: Technology preview: Private contact discovery for Signal

#71

Earlier quoted context omitted.

I don't understand your motivation here. Every time I advocate using Signal I run into a wall of "but it doesn't have stickers"; for those users, all the privacy engineering is moot if the app doesn't fill their needs. Adding another attachment type would do nothing to degrade your experience, nor would it turn Signal into WeChat.

It does degrade it tho. There have to be ui elements to interact with them, you need to be up to date on packs, a market needs to be implemented, maybe payment needs to be introduced, the chat looks ugly full of graphics, etc. Plus, every feature adds vectors of attack and things to maintain. I want this to be a Snowden'ish tool for adults, not giffy. I'm not saying my preferences are any better than yours, just high…

> you need to be up to date on packs, a market needs to be implemented, maybe payment needs to be introduced

You don't need any of that. Certainly none of that is present in Telegram. I don't think you read my original comment in full.

> I want this to be a Snowden'ish tool for adults, not giffy.

Ironically Signal already has Giphy integration, but I suppose you didn't notice because you don't use it—as would be the case with stickers.

Re: Technology preview: Private contact discovery for Signal

#72
post #30

In a previous comment on that Moxie interview story posted here, I complained that OWS doesn't do a great job of building a community or making it excited about its product. Something I forgot to add then: why doesn't Signal have a public roadmap? Almost all open source projects that I've seen have one. Why? Because they are typically community-driven and developed projects and because they rely on the community to b…

previous comment of parent - https://news.ycombinator.com/item?id=15282210

Re: Technology preview: Private contact discovery for Signal

#73

It is actually really neat how DRM tech is being reversed to benefit the consumer and privacy for once! Almost daily you read about yet another new "innocent" tech being exploited and used for some corporate gain, taking advantage of the end-users. It's refreshing to see it go the other way!

TPMs are similar. Initially, there was a lot of resistance to them (for fear of DRM, etc.) but over time we've realized that we can put them to good use after all.

Re: Technology preview: Private contact discovery for Signal

#74

In case someone from Open WhisperSystems is reading: please add stickers. Seriously, I know so many people who are on Telegram just because of its sticker system and won't consider anything without that feature. This comes up again and again in online discussions where Signal is mentioned, and it hurts to see all the care and effort the OWS team has put into providing real security rejected out of hand because of it.…

In case someone from Open WhisperSystems is reading: please do NOT add stickers and junk to your clean and pretty system. I know a lot of people that would leave the service if it turned into WeChat (including me). Stick to the fundamental engineering of privacy as you are doing, and forget the gimmicks.

I think this is an unhelpful suggestion. It seems to me that you're advocating that the developers take an approach which will give them a smaller install base in favor of engineering focus on privacy and security. But communicating privately and securely with someone is impossible if they aren't also using the app.

This is the same problem with PGP/GPG -- it may be incredibly secure, but if no one uses it, it doesn't matter.

Obtusely refusing to use a good system which has broad appeal is working contrary to your own goals.

Re: Technology preview: Private contact discovery for Signal

#75
post #39

Earlier quoted context omitted.

I find it really unfortunate that this is stopping people from adopting Signal. However, I believe that this feature was added last year: https://signal.org/blog/doodles-stickers-censorship/

No, that's a different feature with the same name. That allows you to quickly layer graphics from a built-in set on top of existing photos, like in Snapchat. The "stickers" I'm referring to, in the Telegram/WeChat/LINE sense, are essentially custom emojis, or macros for sending one of a collection of reaction images as its own message. https://telegram.org/blog/stickers-revolution Various communities absolutely rely…

I'm not criticizing you when you say that you need stickers, but please help me understand: how do you rely on stickers to communicate?

I can understand them being a nice UI/UX feature that makes the app more fun, but I cannot possibly imagine that people actually rely on stickers to communicate.

Maybe you mean something different and I'm misunderstanding you?

Re: Technology preview: Private contact discovery for Signal

#76
post #75

Earlier quoted context omitted.

No, that's a different feature with the same name. That allows you to quickly layer graphics from a built-in set on top of existing photos, like in Snapchat. The "stickers" I'm referring to, in the Telegram/WeChat/LINE sense, are essentially custom emojis, or macros for sending one of a collection of reaction images as its own message. https://telegram.org/blog/stickers-revolution Various communities absolutely rely…

I'm not criticizing you when you say that you need stickers, but please help me understand: how do you rely on stickers to communicate? I can understand them being a nice UI/UX feature that makes the app more fun, but I cannot possibly imagine that people actually rely on stickers to communicate. Maybe you mean something different and I'm misunderstanding you?

Not me as an individual, but various communities I'm in contact with have stickers ingrained into their culture and social norms. People collect up to hundreds of stickers for different situations, make their own based on shared iconography, and some even have custom stickers commissioned from artists, of themselves, of characters they've created, etc. For groups that are really invested in stickers, migrating to an app which lacks them would significantly alter their dynamics.

Re: Technology preview: Private contact discovery for Signal

#77

Earlier quoted context omitted.

I don't understand your motivation here. Every time I advocate using Signal I run into a wall of "but it doesn't have stickers"; for those users, all the privacy engineering is moot if the app doesn't fill their needs. Adding another attachment type would do nothing to degrade your experience, nor would it turn Signal into WeChat.

It does degrade it tho. There have to be ui elements to interact with them, you need to be up to date on packs, a market needs to be implemented, maybe payment needs to be introduced, the chat looks ugly full of graphics, etc. Plus, every feature adds vectors of attack and things to maintain. I want this to be a Snowden'ish tool for adults, not giffy. I'm not saying my preferences are any better than yours, just high…

> I want this to be a Snowden'ish tool for adults, not giffy.

Not sure how you could be more condescending here.

Look, I get it. I don't use stickers on messaging apps that support them, and I don't have a "GIF keyboard" or whatever. But plenty of actual adults use them and like them, and don't consider a messaging experience complete without them.

If Signal's goal is to be a niche messaging platform that only hyper-privacy/security-conscious people use, then by all means, leave out the user-fun features that the masses want. But if they actually want to raise the bar for mass-market security and privacy, those features are essential. Maybe that's "lame"or "childish" to you, but that's just how it is.

If the addition of stickers makes you leave the platform, then that's certainly a loss for you and those like you, but it's a huge win for the much-larger group of people who will be attracted to the service.

Re: Technology preview: Private contact discovery for Signal

#78

Earlier quoted context omitted.

Take every possible 10-digit U.S. phone number, for example, and perform a SHA-256 hash on each. Put those phone numbers and their hashes in a lookup table. Now, when a hashed phone number comes in from an anonymous user, look it up in that table and you now know the actual phone number.

I'm not an expert, so bear with me. Could this be thwarted by, say, having Signal add a random salt to every registering number and then advertising the hash of (number)+(random salt) as the final contact, invisible to the end user? Or would that involve Signal maintaining too much information on their users? If that's the case, I could see that being a problem.

The problem with salting the hashes is that they then become useless for contact discovery. The only way I can think of to make it work would require sharing the salt with people trying to find you, but then at that point you just share a real user identifier and short-circuit the whole process happening here.

Re: Technology preview: Private contact discovery for Signal

#79
post #21

Earlier quoted context omitted.

SGX attestation involves a key burned into e-fuses on processors at manufacture; the process was designed to prevent Intel from being able to derive keys used for individual enclaves. Obviously, Intel could have a malicious manufacturing process --- but then, that's the case for any piece of merchant silicon you'd use to build any computer.

If I'm reading the documentation [1][2] correctly, you're overselling the security. Verifying an SGX attestation requires trusting not only the integrity of the per-processor secret keys, but the honesty of an Intel-provided online verification API. The API allows you to POST an attestation report to Intel's verification web service, and get back a response saying "OK" or "not OK". You can use TLS to verify that the…

Can you describe which API you're even talking about? This one?

    /attestation/sgx/v1/report
If so, perhaps you missed this:

> "The Attestation Service verifies the validity of the platform. It is the responsibility of the Service Provider to validate the ISV enclave identity."

This API gives back considerably more than just an "OK" or "not OK". It gives back an attestation verification report (see section 4.2.1 of https://software.intel.com/sites/default/files/managed/7e/3b...)

But beyond that, as noted in the document, this is Intel certifying that the attestation was created by genuine Intel hardware. It also carries a data-at-rest signature in addition to TLS:

> "The Attestation Verification Report is cryptographically signed by Report Signing Key (owned by the Attestation Service) using the RSA-SHA256 algorithm. The signature is calculated over the entire body of the HTTP response."

What Intel is providing here is not too far off from OCSP: the main things that can go wrong with "isvEnclaveQuoteStatus" beyond messages being malformed or signed by untrusted keys are the keys being revoked.

An OCSP server could just as easily lie to you about the revocation status of an X.509 certificate. C'est la vie.

Re: Technology preview: Private contact discovery for Signal

#80

It is actually really neat how DRM tech is being reversed to benefit the consumer and privacy for once! Almost daily you read about yet another new "innocent" tech being exploited and used for some corporate gain, taking advantage of the end-users. It's refreshing to see it go the other way!

Trusted computing, TPMs etc have always been about this scenario. It's just the anti DRM crowd has some people that think the end user is always the person sitting in front of the terminal, and there should never be a way to reduce that person's access.

> It's just the anti DRM crowd has some people that think the end user is always the person sitting in front of the terminal, and there should never be a way to reduce that person's access.

That may be extreme (if it's not a strawman), but a major problem with TPM is that there is no way to give control to the end-user, with the possible exception of customers large enough to demand hardware customization.

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