Mailflow Rules and Office 365 Message Encryption

[A_AronL]

Hey all, 

We have recently implemented a mailflow rule in my environment that disallow's our users from sending SSN numbers, drivers license numbers, etc outside of our environment. The rule is supposed to allow the messages through if the exception of them being encrypted or password protected if it is an attachment is met.

The password protection seems to be functioning correctly but using the built in O365 outlook encryption it is still rejecting the messages. Does this sound like an issue using the built in encryption provided? I moved away from using a DLP policy since it didn't support the exception of encrypting the emails but it looks like I'm back where I started. 

Thanks for any insight into this. 

[#2]

It certainly sounds like it may be a limitation of that built in encryption.

You don’t have AIP P2 licences by any chance do you? You could use that to auto classify and protect content based on a sensitive info type match.