AirChat: Secure Wireless from Anonymous
“We traded bandwidth for freedom, or to be more exact we traded bandwidth for freedom, simplicity and low-cost”
AirChat is designed to give hacktivists an instrument to communicate directly, without using any carrier (e.g. Internet or mobile networks) that could be eavesdropped by third parties for surveillance.
AirChat also implements LAN functionality to allow users to a local network to an AirChat transceiver, and it also has an Internet gateway with Tor and proxy support.
“It has built-in internet gateway capabilities to offer users access to some basics such as tweeting, retrieving twitter streams, downloading news, community related articles, etc. This gateway can can be used whenever an Airchat running station gains a working Internet connection and choose to share it. (this internet access can be anonymized via Tor and the built in proxy support).”
The hacktivists are supporting the tasks in the overall project to implement an encryption mechanism for the ham packet radio communication, that lack of any built in feature to secure data from unauthorized access, and to ignore spectrum and user licensing.
“Initially AirChat used code from
minimodemand then from
soundmodemsources but after suggestions from the ham radio people involved in ARES, we decided to make it modular to use the
Fldigisoftware, a broadly deployed solution for use with ham radios.” reports the original project page.
The principal problem that activists and contributors desire to solve is that activist communicating in a trouble situation doesn’t have time to obtain a ham radio license before they start communicating.
AirChat is based on clear-text broadcasting messages, a transmission is visible to any receiver within range, and uses a specific packet format, the Lulzpacket, to handle error correction and encryption.
AirChat implements two modes of communication:
- clear-text broadcasts to send the messages to anyone within range for “for general broadcasting and community discussion”;
- asymmetric encryption, for anonymous communication. The encrypted messages are received by everyone, but only the holder of the private key can decrypt it;
“Each node only cares for what is being received. No hardware identification, no transmitter plain identification. only packets matter. transmissions are anonymous. whenever an address is needed to reply to a packet, it is encrypted inside the packet.Packets targeting specific addresses are encrypted and they must be decrypted by the private key only the target possesses. ”
The AirChat software works with any transceiver and operates at a frequency chosen by the transmitter, to maximize its efficiency, reducing interferences by authorities its suggested to use unlicensed frequencies.
The hacktivists have anticipated that they are already working to support 4K video streaming and they have already tested image transfers using Google’s WebP format to optimize bandwidth usage.