[Cryptography] WhatApp metadata broken; on deck: voice encryption

[Henry Baker]

FYI -- The authors seem very optimistic about capturing the voice encryption session keys soon.

WhatsApp network forensics: Decrypting and understanding the WhatsApp call signaling messages

http://www.fit.vutbr.cz/research/pubs/index.php?file=%2Fpub%2F10979%2FWhatsApp.pdf&id=10979

we were able to acquire the following artifacts from the network traffic:
* WhatsApp phone numbers.
* WhatsApp phone call establishment metadata and datetime stamps.
* WhatsApp phone call termination metadata and datetime stamps.
* WhatsApp phone call duration metadata and datetime stamps.
* WhatsApp's phone call voice codec (Opus).
* WhatsApp's relay server IP addresses used during the calls.