E-mail encryption

[James Walton]

Hi

I would like to know whether e-mails are encrypted in transit by default in the following scenarios please:

1) Between mailboxes within the same Office 365 tenant

2) Between different organisations who both use Office 365

3) Between Office 365 tenant and an external/non-Office 365 organisation

I've done plenty of reading but can't find a definitive answer on the above.

Thanks

[#2 · Accepted solution]

1) Yes

Encryption occurs in transit and at rest automatically:

Encryption in Office 365

2) Yes, in as much as emails are transmitted over an encrypted connection:

"Exchange Online servers always encrypt connections to other Exchange Online servers in our datacenters with TLS 1.2. When you send mail to a recipient that is within your Office 365 organization, that email is automatically sent over a connection that is encrypted using TLS. Also, all email that you send to other Office 365 customers is sent over connections that are encrypted using TLS and are secured using Forward Secrecy."

How Exchange Online uses TLS to secure email connections in Office 365

3) No, but there are options available such as Office 365 Message Encryption (OME) that can do just that, which

"lets you send encrypted email to people inside or outside your organization, regardless of the destination email address (Gmail, Yahoo! Mail, Outlook.com, etc.)."

Email encryption in Office 365

[#3]

Thanks for the info Cian