Getting Signal on a PocketCHIP

I’m a big fan of the NextThingCo and their $9 CHIP computer for the simultaneously radical and practical approach to hardware manufacturing and low cost computing. Being a fairly early backer of their crowdfunding effort, I was able to get the super fun PocketCHIP dock/case/shell, as well, which looks like a cross between a Blackberry and a Gameboy, with all the circuitous guts exposed. The PocketCHIP is an open-source, handheld, portable computing device, with built-in Wifi and Bluetooth, a hilariously difficult keyboard, and a not so terrible battery. While I have tried to find legitimate uses for it in my day to day toolkit, including as an IoT monitoring terminal for a car’s ODB2 port, I have mostly just carried it to remind myself that the future of mobile computing could be one based on open-source hardware, software and an infinite variety of 3D-printed form factors.

Now, in the last few days, I have become a big fan of Signal-CLI, a Java-based command line interface to the Signal Messenger service. On this very blog, I wrote post on how you can easily send batched encrypted broadcast messages from a terminal shell using it. Then, tonight, I was looking at my PocketCHIP, and I had a moment of inspiration, when I realized that I could easily “apt-get install” java onto it, and by extension run Signal-CLI. This means that I could turn my underused PocketCHIP into a portable, open device upon which to send and receive encrypted messages to anyone in the world who also had Signal.

To make a long story short, it works! I installed Java (“apt-get install openjdk-7-jre-headless”), I downloaded the latest Signal-CLI releases (“wget”), unpacked it (“tar xzvf… ” yada yada), and then ran the signal-cli command line. From there, you just follow the simple instructions provided on Github for registering and verifying, and away you go! I used a Google Voice number to handle receiving the SMS verification code. You could also use any landline or payphone – you just need something that can receive a text or voice call. Make sure to follow all the Signal safety tips, as well!

With Signal-CLI, you can send and receive messages, create and manage groups, and even list and verify safety number “keys”. The limited processing power and memory on the PocketCHIP does cause each command to take a few seconds, but that can be worked around. I can easily imaging an ELM or PINE style user interface for this, that would hide all of that fetching and receiving in a background process.

So, now my PocketCHIP is on Signal, and it has become infinitely more useful. Oh, and did I mention, it also runs Tor? Who is up for writing Ricochet-CLI?

Sending Secure Broadcast Messages with Signal

I have a created a simple Signal batch sending script (, which works with the fantastic Signal-CLI (Command Line Interface) project.

Now, you might be asking, why is this needed, or why wouldn’t I just use a group? Well, there are many cases where a person may want to send an alert or update message to a large group of people, who don’t otherwise want to be associated with each other. This is a one-to-many use case, not a many-to-many. For situations of high risk related to human rights, activism, living under a police state, or these days, even just being a U.S. born NASA scientist, it is a very real threat that your phone might be physically taken from you, and forced to be unlocked. In that case, anyone in any groups you are in would then also be exposed and put at risk, as happened in the tragic story of a Mexican activist.

In some cases, you may want to send messages out to 10,000s of people, for protests, events, concerts, emergencies, and so on. This is a use cases that goes back to the early, pre-Twitter TXTMob and RNC2004 systems I was involved in , except we were just using plain old SMS then, which was expensive and risky. Now, you can do this with fully encrypted messages, sent freely anywhere on the globe, right from your laptop. Neato!

Okay, so how does the script work? Here’s a quick run-down with instructions for any Linux or MacOS system. (This can work for Windows, but someone needs to rewrite the script as a BAT script).

  1. Download Signal-CLI and unpack it somewhere
  2. Download the script and put it into the “bin” folder for Signal-CLI
  3. Create a text file with all of the numbers you want to send to, one per line, with country code (+12125551212)
  4. Open a terminal, and follow, the excellent signal-cli readme instructions on how to register your number (or a new, clean number) with Signal
  5. Once you complete the registration and verification, you are ready to run!
  6. In the terminal type > ./ to see the usage info below

usage: ./signal-batch yourSignalNumber yourBatchList “Your message goes here!”
example: ./signal-batch +12125551212 mygrouplist.txt “This is the broadcast message you requested!”

Before I go, I must state this: DO NOT ABUSE THIS SCRIPT FOR SPAM, DoS OR OTHER MALICIOUS PURPOSES. I am sure your Signal account will be shutdown if you do, and the “this is why we can’t have nice things” bad karmic spirits will reign down on you.

Finally, if you are promoting the use of Signal to high risk communities, please read some of these excellent guides below and making it as safe as possible: