Telegram with Matthew Green

Security Cryptography Whatever

We finally have an excuse to tear down Telegram! Their CEO got arrested by the French, apparently not because the cryptography in Telegram is bad, but special guest Matt Green joined us to talk about how the cryptography is bad anyway, and you probably shouldn't use Telegram as a secure messenger of any kind!
Transcript: https://securitycryptographywhatever.com/2024/09/06/telegram
Links:
- https://blog.cryptographyengineering.com/2024/08/25/telegram-is-not-really-an-encrypted-messaging-app/
- Lavabit / Ladar Levinson: https://en.wikipedia.org/wiki/Lavabit
- Pavel Durov indictment statement from French authorities: https://www.tribunal-de-paris.justice.fr/sites/default/files/2024-08/2024-08-28%20-%20CP%20TELEGRAM%20mise%20en%20examen.pdf
- MTProto 2.0 protocol spec: https://core.telegram.org/api/end-to-end
- https://words.filippo.io/dispatches/telegram-ecdh/
- MTProto 1.0 (old no longer used): - https://web.archive.org/web/20131220000537/https://core.telegram.org/api/end-to-end#key-generation
- OTR: https://otr.cypherpunks.ca/otr-wpes.pdf
- AES and sha2 used in ‘Infinite Garble Extension’ mode: https://eprint.iacr.org/2015/1177.pdf
- Four Attacks and a Proof for Telegram: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9833666
- History of Telegram e2ee chats availability: https://en.wikipedia.org/wiki/Telegram_(software)#Architecture
- https://securitycryptographywhatever.com/2023/01/27/threema/
- https://securitycryptographywhatever.com/2022/11/02/Matrix-with-Martin-Albrecht-Dan-Jones/
- https://en.wikipedia.org/wiki/Matrix_(protocol), introduced in September 2014

"Security Cryptography Whatever" is hosted by Deirdre Connolly (@durumcrustulum), Thomas Ptacek (@tqbf), and David Adrian (@davidcadrian)

Chapter

1. Telegram with Matthew Green (00:00:00)

2. Cryptocurrency and the French Legal System (00:00:12)

3. Telegram's Finite Field Crypto Parameters (00:09:42)

4. Cryptographic Protocol Vulnerabilities and Concerns (00:16:22)

5. Messaging Protocol Security Concerns (00:27:35)

6. Modern Messaging Protocol Security Evaluation (00:31:49)

7. Inadequacies of IGE Encryption Mode (00:35:42)

8. Encrypted Messaging Protocol Vulnerabilities (00:45:29)

9. Cross-Border Legal System Comparison (00:59:08)