Back in November of 2013, Microsoft announced Office 365 Message Encryption (OME) as a way to protect the contents of outbound messages to people in other organizations. This excellent update helps fence in it's predecessor, Exchange Hosted Encryption (EHE), to the Office 365 branding and management. Users of EHE had to work through more cumbersome configuration steps and were required to purchase it open volume licensing, whereas OME comes included as part of Azure Active Directory Rights Management (AADRM) in the E3 and E4 packages, or purchased as an add-on to other enterprise SKUs with the normal subscription licensing.