Cryptanalysis II
summary
Reverse-engineering of Bridgefy shows Bluetooth mesh uses Gzip then RSA PKCS#1 v1.5 per-block, letting an attacker perform a compression-oracle style decryption with about 2^17 chosen ciphertexts, impersonate users because the handshake lacks authentication, and mount zip‑bomb DoS; attacks are verified on Android using Frida and disclosure led to a claimed Signal migration not yet reviewed. Analysis of GAEN shows cheap Inverse‑Sybil attacks by sharing key material; two hash‑chain protocols are proposed (non‑interactive or location‑derived) that raise server trust and download costs. Time‑shift attacks via NTP/Wi‑Fi/rogue BTS let adversaries replay keys to inject false alerts; regional bulletin boards show practical replay exposure.
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chapters (13)
- 0:00Intro
- 1:45Other examples
- 3:19Research
- 9:46Lessons
- 12:59Replay Attacks
- 15:09Gain Scheme
- 17:17Investible Attacks
- 18:50Overview
- 20:47Summary
- 22:29Presentation
- 25:29Keep it stupid simple
- 28:59How does it work
- 31:19Master of time attack
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