In the latest report by Citizen Lab, it was found that Zoom created its own encryption protocol. Zoom claimed that they were using AES-256 versus the AES-128 encryption method as discovered by the Citizen Lab report.

Given the substandard security, vulnerabilities and Zoom-bombing. It is best to seek alternatives.  If you are already using Office 365, Teams is already support in your environment.  

Source: https://citizenlab.ca/2020/04/move-fast-roll-your-own-crypto-a-quick-look-at-the-confidentiality-of-zoom-meetings/