Better late than never: Microsoft rolls out a public preview of E2EE in Teams calls

October 22, 2021 TH Author

Microsoft has finally kicked off the rollout of end-to-end-encryption (E2EE) in its Teams collaboration platform with a public preview of E2EE for one-to-one calls.

It has been a while coming. The company made the promise of E2EE for some one-to-one Teams calls at its virtual Ignite shindig in March this year (https://www.theregister.com/2021/03/03/microsoft_ups_security/) and as 2021 nears its end appears to have delivered, in preview form at least.

The company’s rival in the conference calling space, Zoom, added E2EE for all a year ago, making Microsoft rather late to the privacy party. COO at Matrix-based communications and collaboration app Element, Amandine Le Pape, told The Register that the preview, although welcome, was “long overdue.”

“It’s worth noting,” she went on, “that even if the calls are encrypted, users will be completely dependent on a single supplier (Microsoft) to host and secure them – they are putting all their eggs in one basket. Meanwhile, text chat and voip/video conferences remain unencrypted.”

Then again, as Element found to its embarrassment, everything in E2EE is not entirely straightforward after a whoopsie in the Matrix key sharing scheme could have resulted in the compromise of user keys.

As for Microsoft’s implementation in Teams, only real-time media flow (voice and video) for one-to-one calls can be encrypted and the feature must first be enabled by an administrator before users can turn it on. It is not activated by default.

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The platforms are a bit limited too. The latest Teams desktop client for Windows or Mac is needed, or an up to date app on iOS and Android. Once a user turns on E2EE in one place, however, it will be turned on for all their other supported endpoints. Teams’ Public Switched Telephone Network (PSTN) functionality does not support E2EE and chat in E2EE calls remains secured by Microsoft 365 encryption.

Other features – such as live captioning and transcription, call transfer and merging or adding another participant to turn a one-to-one call into a group call – are not supported, although Microsoft said: “We will work to bring end-to-end encryption capabilities to online meetings later.”

In the meantime, customers will just have to put their faith in Microsoft 365 encryption where E2EE is not an option. ®