So you generate a handle, maybe even a key pair and upload the public half to a server. Then someone you know joins next week and does the same.

How do you find each other?

If it's feasible for an end user, say 30 seconds of a phone's CPU, you can be sure that a spammer could generate millions.

> How do you find each other?

You don't, because that's something that's fundamentally impossible to do in a privacy-preserving way - no way around it.

> If it's feasible for an end user, say 30 seconds of a phone's CPU, you can be sure that a spammer could generate millions.

You're picking overly conservative numbers for "feasible". Choose parameters such that it takes something like half an hour on a phone. Inconvenient? Yes, but privacy is inconvenient in general.

And yes, a spammer will still be able to generate lots of these fake identities, but now the cost is much higher, while the expected profit is roughly the same - and that's how you defeat spam.

Well there are alternatives to signal. Some use p2p, some use tor, some use a federated system of servers. None have the networking effect to be as secure and as popular as signal.

So if signal was privacy preserving, didn't show or tell contacts about others using the service, do you think it would be as popular? Or do you think we'd be discussing a different popular e2e encrypted app and complaining about the very features that made it popular?

It sounds like you want an app that sacrifices usability for a promise of security. That's fine, there are options. Of course, some are honeypots run by the US government, and you'd need to really really have an unusual threat model to warrant such care, but you do you.

>How do you find each other?

by exchanging public keys over an established communication channel

>If it's feasible for an end user, say 30 seconds of a phone's CPU, you can be sure that a spammer could generate millions.

yeah, that's an inherent limitation of PoW, so it has to be an option rather than a requirement. then people who don't care about privacy can do the SMS thing, and those who do can opt to do the 30 minute PoW.

but this is irrelevant to Signal. it's not the phone number verification itself that people have problem with. if the only purpose it served was to prevent attacks on the service by ratelimiting it to one account per one phone number, that would be largely fine. the problem is that your phone number is your Signal identity, which is utterly moronic for a "privacy-first" service, and the reasoning and excuses for this stink to high heaven.

> by exchanging public keys over an established communication channel

I get the appeal, but seems like requiring out of band key exchange will add significant friction and make signal much less popular compared to the competition. I've got a few dozen signal contacts, only a few of them close enough to do a key exchange. If I only had a few, not sure I'd use signal.

Signal has been resisting making special cases for the few, and I get it. Why spend developer time on some feature that's not going to benefit the majority of users?

> the problem is that your phone number is your Signal identity, which is utterly moronic for a "privacy-first" service

I can't think of anything that would work as well and result in so many (40M monthly) people communicating securely. They do seem to be considering their options to help with this, in particular: https://signal.org/blog/secure-value-recovery/

Allowing social networks, surviving the death of your phone, frictionless on boarding, account recovery, etc all interact in complex ways.

Personally I like that there's not a contact database/social graph inside signal.

>requiring out of band key exchange will add significant friction

how do you exchange phone numbers and email addresses with people?

>and make signal much less popular compared to the competition

is popularity among the (COMPLETELY) tech-illiterate worth giving up privacy for?

>I can't think of anything that would work as well and result in so many (40M monthly) people communicating securely.

and virtually everyone who had ever used the internet has an email, despite its apparently cumbersome sign-up and contact discovery procedures.

>surviving the death of your phone, ... , account recovery

are less likely if your account is tied to the phone number or email. they can be lost, they can be stolen, they can be seized.

> How do you find each other?

I don't want to find people on Signal, or be found by them. I want a way to securely communicate with people I've decided I trust enough to be contactable by them - that is, people I've met and sufficiently liked face to face.

I’ve always thought it is dumb for the same reason i think WhatsApp is dumb. In Latin America, WhatsApp exists as a way for people to message each other without paying per text, which is very much still a thing down there. In the US, we get all of our everything unlimited, so we don’t need a wacky app to send texts without paying more money.

But why then do you even need a phone number to use WhatsApp? If it is a texting and calling service that is used to circumvent carrier fees, and is almost exclusively used on WiFi (because data is even more expensive than texts), why not just let them make an account and not use the phone number? That way they don’t have to pay a secondary company to use WhatsApp…