View source for Sat Messenger / RBS

Work in progress

== What ? ==

* It's an *encrypted* short message gateway : email/web <- iridium constellation -> Everywhere on earth
* To reduce cost, a specific encryption is used through the satellite infrastructure part. Of course, one can add final PGP to our code.
* Each 50 character long messages can be 0.05 euros. Remember the SMS at the beginning ?
* Messages follow : destinationemail text

foo@bar.com I'm fine

* Sat messenger is the satellite part of RBS project : Recovery Base Station. It's a cheaper and encrypted version of University of Berkeley [http://kurti.sh/pubs/rbs-dev14.pdf "Rescue Base Station"]


"API" refers to rock7 API.

== RBS ==

* There is a info website about this [http://www.satmessenger.org project]

== Sat Messenger ==

=== Somewhere to Internet via sat ===

Sending a message from everywhere with a sat device, is called "Mobile Originated" (MO).
Different codes are available for the "computer" (Raspberry 1 is ok) connected to the sat modem. 

* web form run locally (python + twisted)
* command line tool "mo".

Once satellite forwarded the text to the ground, the API can send to an email or to a http POST server.
Obviously sending directly to destination email defeat the purpose of privacy.
"Mainserver" code can receive the API http POST, decrypt and email the text to destination. (python + twisted)

=== Internet to Somewhere via sat ===

It's a "Mobile Terminated case (MT). These programs make the http POST connection to the API

* web form (python + twisted)
* command line tool "mt".

* rock7 website, but with no encryption.

Like voicemails, to receive messages, one need to start a connection to satellite, ask for queued message and get them one by one.

=== Hardware ===

* Satellite communication are based on "Short Burst Data", SBD,  message with a 9602 Modem
* All in one version (antenna, modem) can be found at rock7.com. We own a [http://www.rock7.com/products-rockblock-plus Rockblock +]

=== Test computer version ===

=== Embeded version ===

* Raspberry based

=== Software ===

* rock7 documentation is sometimes wrong. i.e serrial communication with the modem use actually the standart 0D 0A end of line.
* [http://www.makersnake.com/rockblock/ makersnake] [https://github.com/MakerSnake/pyRockBlock library] is a great start for the python way. Altough some URL has changed and some script are not complete. Most of our end user code is heavily based on the awesome works makersnake published.

=== Crypto ===

* Iridium SBD Messages are transmitted as is. So if you type clear text, it will be transmitted in... clear text. That's really sucks.
* In the RBS scenario, because a major event (earthquake,...), there is no possible communication other than the previous sat messages. We use some short stream ciphers and hash functions.
* There is probably better choice, but the goal was to encrypt, we welcome crypto experts to improve this part.