S/MIME in Office 365
S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for public key encryption and digital signingof MIME data. Configuring S/MIME in Office 365 is a slightl...
Updated Aug 26, 2026
Version 3.0
Blog Post
Great article. Very detailed and clear! Thank you for that.
As I understand we can only use this to sign messages in our own organisation?
Quote : Cross Org/Cross Tenant S/MIME is not supported in Outlook Web App and EAS (Exchange Active Sync)
Can we send messages with S/Mime to external users?