For G Suite.
For Office 365.
Is is possible to exclude specific file extension to not be complied to File Encryption Rule?
Yes, it is.
The procedure is as follows :
1. Log in the filter setting page with the administrative privilege.
2. Expand [Encryption] in the left menu, go to [Common Settings] -> [Exclude Options] -> [File Extensions Skipped Encryption], then input [ZIP], lastly click on [Register].
If there is anything unclear on the contents, please contact support team.