Posts that travel at walking speed, over LoRa radio, on loraline.
Nothing is routed. A node keeps what it has heard and offers it to whoever comes into range, so a post reaches you because a person walked between you and its author, possibly through several others first. Your audience is geography: everyone within earshot, and nobody beyond it. You cannot build a following and you cannot go past your radio horizon.
At SF7 under a one percent duty cycle a node has thirty-six seconds of airtime an hour. A 140 character post costs 871 milliseconds to put on the air, which owes eighty-seven seconds of silence. That is about forty posts an hour including everything relayed.
For four or six people that is not scarcity, it is more than anybody would write. But it settled three things before any of this was built:
- Posts are short. 140 characters, and the signature alone is eighty-eight.
- Nothing is ever sent to somebody who already has it. A meeting is: here is what I hold, then send me these, then here they are.
- A meeting hands over six posts at most, so one node cannot spend another's whole hour.
A post is signed once by its author and the signature travels with it for ever. A carrier can drop a post, refuse to pass it on, or lie about where they got it. What they cannot do is change a word of it or write one in somebody else's name: the address is recomputed from the keys carried with the post, so an invented signing key cannot be attached to a real name.
The trail of who carried it is a claim, not a proof. Signing every hop would make it provable and cost eighty-eight characters a time, which at forty posts an hour is not a trade worth making.
A name and a twelve by twelve picture in eight colours, signed and carried exactly as a post is. It has to be signed: the person reading it has almost certainly never met the person it describes, and a carrier handling somebody else's face is precisely where forgery would matter.
A profile is 731 characters on the air, sent once and then only when it changes. That owes 237 seconds of silence, against thirty-six seconds an hour, which is affordable exactly because nobody changes their face twice a day.
It can be a photograph. Every picture brings its own eight colours, chosen from the image itself, because a fixed palette is fine for something drawn and hopeless for a face. Twelve square made a face a blot and twenty-four lost the eyes: at that size a pupil is one pixel and eight colours cannot spare one for it. Thirty-two is where a photograph still looks like the person, at 731 characters, sent once.
Sharpen first and do not dither. Dithering scatters a one pixel eye across three pixels of nothing.
Open hearsay, find you at the bottom of the page, and click use a photograph. Pick any image; the node squares it, takes the head end, reduces it to thirty-two pixels and eight colours chosen from the picture itself, signs it, and hands it on from then on.
The browser only shrinks it to 256 square first, which is a size guard rather than the reduction: there is no sense pushing sixteen megabytes of a phone photograph at something that will keep a thousand pixels of it. The reduction itself happens in one place, in the node, so everybody's face is made the same way.
Everybody has a face before they draw one. The default is derived from your address, mirrored down the middle, in two of the eight colours. A stranger arrives already looking like somebody rather than like a blank.
Faces are offered rather than asked for, a few at a time, because a post from somebody with no face beside it is a worse thing than a few hundred characters spent unprompted. The newest profile wins, and an older one cannot undo it.
Two hundred posts, oldest forgotten first. A node is a person's pocket, not an archive. Something it once held and let go is not asked for again, or two nodes would trade the same post for ever.
There is no ranking and nothing is promoted. The only thing that ever happened to a post is that people carried it, and how far it has come is already visible.
git clone https://github.com/intervalplace/loraline
git clone https://github.com/intervalplace/hearsay
pip install -r hearsay/requirements.txt
cd hearsay && PYTHONPATH=../loraline python tests.py
Then, with a radio:
export LORALINE_KEY="the phrase your town agreed"
PYTHONPATH=../loraline python -m hearsay --name yourname \
--port /dev/ttyUSB0 --band eu868
Open localhost:8080. Without a radio, --tcp-listen 4242 and
--tcp-connect somewhere:4242 will do for trying it.
It wants to stay running. A node that is only on while you are looking at it carries nothing: the whole mechanism is holding posts between meetings and handing them on when somebody passes. It belongs on something that stays on.
The pocket is written to disk beside the identity and read back at startup, and everything in it is verified on the way in exactly as if it had arrived over the air. A file is no more trustworthy than a stranger.
Without this a node forgot everything it was carrying whenever it restarted, which for a daemon whose entire job is to hold things between meetings is not a small bug.
MIT.