An intro to mobile messaging security in text messages and messaging apps. Presented at CryptoParty NYC at Brooklyn Public Library.

1. 😧📱🔓🕵📱😩
David Huerta - CryptoParty @ BPL 11/9/2015

2. Plain Text Messages
• Encrypted only between telco and device
(sometimes).
• Telco can read everything you type, so can their
friends.
• Bonus: This also means your plain phone calls can
be intercepted.
• Bonus: It's not just the Telco you have to worry
about...

4. Stingrays
• Used by law enforcement to intercept (and copy)
cell phone text messages, phone calls, and
location data.
• Usually mounted in a van or plane.
• More info on their legal use: https://www.eff.org/
deeplinks/2015/09/finally-doj-reverses-course-and-
will-get-warrants-stingrays.
• $13,500 per unit (barely over $9,000)

6. Software Defined Radio
• Could be used by just about anyone with some
tech expertise.
• Julian Oliver's The Beacon Frame an example that
just broadcasted messages rather than recording
them.
• Others may have few scruples.
• HackRF: $299

7. 0€ with CCC ticket

8. Messenger Apps
• Many messenger apps offer different levels of
protection to defend against people intercepting
the wireless signal, but usually these are
incomplete.
• See how incomplete here: http://
projects.propublica.org/graphics/privacy-tools
• …and… https://www.eff.org/secure-messaging-
scorecard.

9. – Everyone
“Which secure messaging app should I use?”