If one is to believe their blog post (
https://blog.zoom.us/wordpress/2020/04/01/facts-around-zoom-...), then they do in fact use end-to-end encryption:
> To be clear, in a meeting where all of the participants are using Zoom clients, and the meeting is not being recorded, we encrypt all video, audio, screen sharing, and chat content at the sending client, and do not decrypt it at any point before it reaches the receiving clients.
The first problem is:
> Zoom currently maintains the key management system for these systems in the cloud.
Obviously, this compromises many of the benefits of e2e encryption. Having said that, it doesn't remove all of the benefits, and it's a (bad) precedent that has been set by other companies (eg. apple) where keys for end-to-end encrypted communication are backed up to the cloud.
The second problem is that Zoom has a second class of "client" called a "Connector" which runs in the cloud, and also has access to the keys for decrypting the stream. I definitely think that when one of these connectors is being used, it is false advertising to show the "e2e encrypted" status. However, there are clear technical reasons why these connectors are needed. Being able to dial into a meeting from an ordinary phone is important functionality that simply cannot support end-to-end encryption.
The interesting section to me is the later paragraph:
> For those who want additional control of their keys, an on-premise solution exists today for the entire meeting infrastructure, and a solution will be available later this year to allow organizations to leverage Zoom’s cloud infrastructure but host the key management system within their environment. Additionally, enterprise customers have the option to run certain versions of our connectors within their own data centers if they would like to manage the decryption and translation process themselves.
In particular, being able to use your own key management system would make this truly end-to-end encrypted by any definition, even if you are still using Zoom's cloud infrastructure.