Couldn't find the one I have read before. But here are a few that I could find. https://eprint.iacr.org/2017/713.pdf https://eprint.iacr.org/2017/713.pdf htt

Couldn't find the one I have read before. But here are a few that I could find. https://eprint.iacr.org/2017/713.pdf https://eprint.iacr.org/2017/713.pdf https://www.researchgate.net/publication/312778290_WhatsApp_security_and_role_of_metadata_in_preserving_privacy https://www.researchgate.net/publication/312778290_WhatsApp_... https://www.ijrte.org/wp-content/uploads/papers/v8i2S3/B10930782S319.pdf https://www.ijrte.org/wp-content/uploads/papers/v8i2S3/B1093...