Cifra-te ou Devoram-te
# 01010110010101011
Introduction to Secure Communications
Source: Bunkerfunkeror (CC-BY-SA-3.0)


  • Advertisements & Surveillance = ♥
  • Centralization ate the cat :(
  • We can get killed based on metadata
  • Data acquisition is toxic
Michael Hayden
former director of CIA and NSA
Source: Briar 34c4

Overview of (some) communication protocols/systems

  • Instant messaging
  • Voice over IP
  • Email
  • IRC
Instant messaging
Source: Heimdal Security
Source: Briar website
  • Centralized servers
  • Expose messages, contants, relationships,...
  • Censorship, content filtering, information controls
  • Prone to attacks: DoS, MiTM,...
Source: Briar 34c3
  • No End to End Encryption (/by default)
  • Home-grown crypto protocols
  • Insecure defaults
Source: Briar 34c4
  • Phone numbers as identifiers centrally stored → Juicy Target
  • Timing Attacks
  • Logs, other metadata...
Source: Briar 34c4
Source: Briar 34c4
Source: Briar website
  • No central server required
  • No phone numbers
  • Connectivity: Bluetooth, LAN, Tor
Source: Briar 34c4
  • Connection between peers consists of 6 Tor relays (3 picked by each peer)
  • Hides metadata even from network observers