A very common question I get is about how secure information is in Office 365. The above video shows you how SharePoint Online data is saved when at rest.
Microsoft do a lot in my books to ensure that data stored in Office 365 is secure as possible and in my books far more secure that most people achieve on premise. That means to me security is a major reason to CHOOSE the cloud over anything on premise.
Security is a journey and not a destination I know but Microsoft have the resources to ensure that the information they maintain is a secure as possible and I’m comfortable with that.