Microsoft is working on expanding the capability to revoke encrypted email messages sent using the Office 365 Message Encryption (OME) service to regular users as part of a larger effort to prevent data leaks and enterprise data theft.
OME is built on Microsoft Azure Rights Management (Azure RMS) and it combines rights management with email encryption capabilities.
It allows Office 365 customers to send and receive encrypted emails using Outlook.com, Yahoo!, Gmail, and several other email services with support for encryption, authorization, and identity policies.
Encrypted email revocation for end-users
“As part of Office 365 Advance Message Encryption, we are