Content in Microsoft Teams, Microsoft 365 Groups, and SharePoint is automatically encrypted at rest and in transit.

Encryption at rest

When a file is saved in a Microsoft 365 Group, the file is automatically encrypted while it is stored in the cloud. 

Encryption in transit

When someone downloads or reads/writes a file, the traffic on the network is also always automatically encrypted because the Microsoft 365 service is using HTTPS/SSL/TLS as transport protocols (note that these are encrypted protocols). 

More information

• For examples and more information on Encryption in Office 365, visit Microsoft's information on Encryption in Office 365

• For more details about encryption specifically in SharePoint Online and OneDrive for Business, visit Microsoft's documention