The recipient's machine uses a key to decrypt the message, orĪ central server decrypts the message on behalf of the recipient, after validating the recipient's identity.įor more information on how Microsoft 365 secures communication between servers, such as between organizations within Microsoft 365 or between Microsoft 365 and a trusted business partner outside of Microsoft 365, see How Exchange Online uses TLS to secure email connections in Office 365. Once the message is received by the recipient, the message is transformed back into readable plain text in one of two ways: The message remains in ciphertext while it's in transit in order to protect it from being read in case the message is intercepted. Here's how email encryption typically works:Ī message is encrypted, or transformed from plain text into unreadable ciphertext, either on the sender's machine, or by a central server while the message is in transit. For example, Microsoft 365 uses Transport Layer Security (TLS) to encrypt the connection, or session, between two servers. In the service, encryption is used in Microsoft 365 by default you don't have to configure anything. Microsoft 365 uses encryption in two ways: in the service, and as a customer control. How Microsoft 365 uses email encryptionĮncryption is the process by which information is encoded so that only an authorized recipient can decode and consume the information. Learn details about signing up and trial terms.

Start now at the Microsoft Purview compliance portal trials hub. If you're not an E5 customer, use the 90-day Microsoft Purview solutions trial to explore how additional Purview capabilities can help your organization manage data security and compliance needs.

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