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.

  • jagged_circle@feddit.nl
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    35 minutes 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

  • Ferk@lemmy.ml
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    3 hours 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.

    • VubDapple@real.lemmy.fan
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      1 hour 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.

  • root@lemmy.world
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    7 hours 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.

  • foremanguy@lemmy.ml
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    6 hours 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.

  • ERROR: Earth.exe has crashed@lemmy.dbzer0.com
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    10 hours ago

    Briar (Android Only) - Uses Bluetooth, Wifi, or Internet via Tor to communicate. You can theretically create a large mesh group with enough users. Think of protests where the government shuts down the internet. Downside is, bluetooth range is 10 meters 😓.


    Also: You can send encrypted text over SMS using Secure Space Encryptor (SSE) (known as Paranoia Text Encryption on iOS). It’s an Open Source app that can encrypt text.

    1. Type text
    2. Copy the Ciphertext
    3. Send and tell the recipient to use SSE fo decrypt.

    You both have to share a password/passphrase over a secure channel, then use that to encrypt and decrypt.

    Or PGP (there are mobile apps), but they aren’t quantum resistant. If someone intercept and stores them, it could be decrypted later. So I recomment Symmetric Encryption like AES 256 (so use SSE for better security, since they use AES 256)


    You can also encrypt a radio:

    Rattlegram is an app on iOS/Android that alllows converting text to audio and play it over your phone’s speaker.

    As mentioned before, SSE.

    1. Use SSE to encrypt text
    2. Copy-Paste the Ciphertext to Rattlegram
    3. Sent it over the radio
    4. On the other end, use Raddlegram to turn the audio back to the ciphertext
    5. Use SSE to decrypt.

    Voila! Off-Grid Encrypted communications.

    Warning: Encryption over Ham Radio bands is illegal in many countries 😉 (but fuck the law lol, who cares)

    There’s also Meshtastic, but it has much shorter range, but, in the USA at least, they aren’t “Ham Radio” so they (supposedly) can be encrypted legally.