https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto-a-quick-look-at-the-confidentiality-of-zoom-meetings/
"We determined that the Zoom app uses non-industry-standard cryptographic techniques with identifiable weaknesses. In addition, during multiple test calls in North America, we observed keys for encrypting and decrypting meetings transmitted to servers in Beijing, China.
An app with easily-identifiable limitations in cryptography, security issues, and offshore servers located in China which handle meeting keys presents a clear target to reasonably well-resourced nation state attackers, including the People’s Republic of China."
"We determined that the Zoom app uses non-industry-standard cryptographic techniques with identifiable weaknesses. In addition, during multiple test calls in North America, we observed keys for encrypting and decrypting meetings transmitted to servers in Beijing, China.
An app with easily-identifiable limitations in cryptography, security issues, and offshore servers located in China which handle meeting keys presents a clear target to reasonably well-resourced nation state attackers, including the People’s Republic of China."