TextSecure, RedPhone, and Signal threat modeling

TextSecure, RedPhone, and Signal threat modeling: TextSecure, RedPhone, and Signal threat modeling

In this blog post I will explore what telecommunication companies (telcos) are able to observe in terms of metadata and content when using or not using Open Whisper Systems’ TextSecure, Signal, and RedPhone. This blog post is independently licensed as “CC0″, because I hope that it might influence EFF’s Surveillance Self Defense guide. Special thanks to John Brooks for content editing.

Introduction

Telecos, globally, for over a hundred years, have had various data retention policies that include metadata and content collection and storage (information seizure). In the United States, the Communications Assistance for Law Enforcement Act (CALEA) was enacted specifically to enhance electronic surveillance. Anything the telecos can see and store, intelligence agencies and law enforcement have the ability to obtain too, often in real-time (information search). Intelligence agencies store this information for much longer than telcos because of the monetary costs to store your private information. Within the Snowden revelations, top secret documents make clear that as much information as possible is collected depending on company/agency capacity and technical capability.

The mobile devices that you use contain a huge swath of information about you. They also contain a huge swath of information about the people that you communicate with. In each of the scenarios that I explore below, I’ll be breaking down my exploration into two high-level categories; device vulnerabilities, which can alternatively be thought of as “data at rest”. The second high-level category is infrastructure threats, which can alternatively be thought of as “data in motion”.