this post was submitted on 30 Jan 2025
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Privacy

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We all know Signal, Matrix, Telegram, SimpleX, etc... But if you can't access the internet you can't communicate. Pretty logic. But would it be possible, at least theoretically, to create an app that permits to message people even if the internet goes down?

It might be a dumb question I really have no idea to be honest.

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[–] [email protected] 10 points 4 days ago

Briar or meshtastic

[–] [email protected] 49 points 5 days ago (1 children)

The first thing that comes to mind is Meshtastic: https://meshtastic.org/

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[–] [email protected] 10 points 4 days ago (2 children)

Telegram isn't P2P and isn't recommended. Signal is good, but not P2P. Matrix is decentralized, not P2P. SimpleX is P2P, I think, but not sure.

[–] [email protected] 5 points 4 days ago

SimpleX uses onion links

[–] [email protected] 2 points 4 days ago

Simplex uses Severs, you can bring your own one, but it is not peer to peer when talking about direct communication to the recipient

[–] [email protected] 5 points 4 days ago

It’s not p2p but at least many years ago:

SMS.

If the Internet outage is local then the towers would still work and you’d be able to get texts. I went through a few storms where wired home internet was down, the towers weren’t giving me a data connection (no mobile web browsing or anything), but I was able to send and receive texts.

If you really care about what you’re asking after, do what someone else said and get a radio license. It’s 150 year old technology and every time something happens radio operators pop up some kind of emergency communications or bridge to the internet through repeaters or something.

[–] [email protected] 20 points 5 days ago* (last edited 5 days ago)

Depending on how far you're willing to push the definition of "messaging" you could look into getting your ham radio license. It can't possibly be censored and allows you to communicate all over the world. You can even build your own radios if a government cracks down on them for some reason.

[–] [email protected] 21 points 5 days ago

Meshtastic can be encrypted and is LoRa based. Can easily hit nodes dozens of miles away with a good line of sight. It also relays messages across nodes to reach even further distances.

[–] [email protected] 31 points 5 days ago (2 children)

I mean this is a terrible answer, but DS pictochat fits that

[–] [email protected] 10 points 5 days ago

No joke, I was talking about this recently. I feel like niche groups (me included) are just going full-circle back to the DS days

[–] [email protected] 2 points 4 days ago

pictochat FTW

[–] [email protected] 15 points 5 days ago* (last edited 4 days ago)

This was a common thing that was developed for the international protests after Arab Spring, which would frequently have their Internet shut down as a State tactic to prevent communication amongst protestors.

Mesh net chat apps like FireChat were born in response

https://en.m.wikipedia.org/wiki/FireChat

Edit: apparently wikipedia says it wasn't developed for protests, it just happened to be released at the same time

[–] [email protected] 8 points 5 days ago (1 children)

yggmail is a fairly obscure and experimental take on email on a mesh network: https://github.com/neilalexander/yggmail

[–] [email protected] 2 points 4 days ago (1 children)

Would this work through something like meshtastic?

[–] [email protected] 2 points 4 days ago

yggmail specifically, probably not. yggdrasil uses TCP/IP and the Meshtastic latencies to perform connections would be too high AFAIK. It would probably only work in a fairly well-connected network. yggdrasil could be used directly over a WiFi protocol but it would need fairly good reception to function.

N.B. I haven'texperimented with this myself.

[–] [email protected] 11 points 5 days ago* (last edited 5 days ago)

Yes, it's possible. To be honest, I find it very sad that we have grown so dependent on ISP and big telecom companies to have a working network.

In theory, you could have an infrastructure in your neighborhood and be able to play Quake with your neighbors without making use of the phone line at all, completely free of monthly fees and with a very efficient and fast connection too! you'd just need cabling connecting the apartments/houses and some decent routers controlling/restricting access on each subnet. It's a pity that's not a standard thing when designing residences.

Though less efficient and more limited in range, you can technically do it with Wifi and mesh networking too... there are projects like B.A.T.M.A.N (https://www.open-mesh.org/), however, it's not very user-friendly to set up. I believe there have been some projects that attempted to launch embedded devices to act as mini routers for this, but the spread has not been wide enough to make it worth it, sadly.

[–] [email protected] 10 points 5 days ago* (last edited 5 days ago)

Briar has a mesh mode. And i think there was a matrix app doing this too?

[–] [email protected] 16 points 5 days ago
[–] [email protected] 6 points 4 days ago (1 children)

Yea but there are android versions too. Its to send files over WiFi direct phone to phone with no network but some also have chat.

[–] [email protected] 3 points 4 days ago

Oh interesting! I'll take a look into it thanks.

[–] [email protected] 11 points 5 days ago

Check out Reticulum Network Stack using LORA radio. Works really well.

http://reticulum.network/

[–] [email protected] 15 points 5 days ago* (last edited 5 days ago) (2 children)

Besides the already mentioned [Briar] (https://briarproject.org/), there's Berty, can't speak to its quality since I never used it, but I always found the project neat in and of itself

[–] [email protected] 3 points 5 days ago

Woah Briar is really cool. I think this is like what I want Signal to be.

[–] [email protected] 2 points 4 days ago (1 children)

I found Berty yesterday just after making this post. But as a neophyte in cryptography and everything, how am I supposed to know which one is better for my privacy ? (e.g. between Briar and Berty) Because right now the only thing that I have is what the apps are "telling" me so... Yeah I don't know how to chose.

[–] [email protected] 2 points 4 days ago* (last edited 4 days ago)

Honestly if you don't want to think too much about it, go with Briar, it's way more battle tested, while Berty seems like it hasn't seen much adoption since it's younger, both have a bit of development activity I saw, so I can't say if one is more or less maintained than the other

As for the actual question of gauging which has the better cryptographical implementation, I don't know either, beside the most surface level information I know very little.
I believe if you want to look into it, you'll have to start from their whitepapers

[–] [email protected] 4 points 4 days ago

positive-intentions is a decentralised P2P chat app. https://positive-intentions.com/

[–] [email protected] 8 points 5 days ago (1 children)

Surprised nobody mentioned scuttlebutt yet https://scuttlebutt.nz/

[–] [email protected] 8 points 5 days ago

SSB can use the internet to share encrypted messages via hubs/servers, but it also can share the same messages peer to peer in a mesh sort of setup without the internet using a 'gossip' protocol within a local network. It was invented by a sailor who was regularly away from WiFi due to being at sea.

[–] [email protected] 9 points 5 days ago

If you don't want to use internet the only ways are to use radio or deploy your own network infrastructure (optic fiber or cell tower), so there's no really any messaging app that can be used without internet. Briar can use Bluetooth but with a limited range, needing an actual dense mesh network.

[–] [email protected] 2 points 4 days ago
[–] [email protected] 10 points 5 days ago (4 children)

There used to be one years ago that used WiFi radios or Bluetooth or whatever so you could chat to people near you... I totally forget what it was called though.

[–] [email protected] 12 points 5 days ago (5 children)
[–] [email protected] 4 points 5 days ago (1 children)

Bridgefy was used more during protests since it's available on both iOS and Android, while Briar is Android only.

[–] [email protected] 3 points 5 days ago* (last edited 5 days ago) (1 children)

Bridgefy seems to require an online account to use. Brair requires zero obline accounts, and even allows sharing the apk to nearby devices without internet.

Edit: Yea, just checked... Bridgefy requires an internet connection the first time you launch it. Not good...

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[–] [email protected] 4 points 5 days ago (1 children)
[–] [email protected] 3 points 5 days ago

Yes, this is totally what I was thinking of!

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[–] 0x0 4 points 5 days ago

I think SimpleX is mesh?

[–] [email protected] 6 points 5 days ago

yes, a lot of people were using those kinds of apps during the free hong kong protests, they go from device-to-device with no internet in between.

No idea what the app is called, but apps like those exist

[–] [email protected] 4 points 5 days ago

This one works, if you don't mind a little diy and texting only: https://circuitmess.com/products/chatter-lora-communication-device

[–] [email protected] 4 points 5 days ago* (last edited 4 days ago) (1 children)

scratch telegram off that list, put Session messenger there instead.

Telegram isn't private, one guy has the master key to the whole thing

[–] [email protected] 2 points 4 days ago (1 children)

Yeah to be honest I don't even know how telegram became so popular in the "privacy-oriented world"

[–] [email protected] 1 points 2 days ago

It's not owned by Meta and it's relatively well-known. It's older than Signal.

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