Google Message Encryption Administration Guide - Manual (Page 44)

Message Encryption, Inbox Delivery 45
3. Recipient Decryption
When the recipient receives the message, the message includes explanatory text
and an HTML attachment. The recipient opens the attachment using a standard
web browser, which launches JavaScript functions to allow secure reading. If
necessary, the recipient will enter a password for future decryption. The recipient
can only the message, read the text, and reply or forward the message if desired.
Filtering
Before a message is routed to Message Encryption, the email security service
applies the same filter rules as all outbound mail.
The Email Security Service filters all mail before sending it to the recipient. All
Attachment Manager or Virus filters still apply.
Content Manager rules with a disposition of “Message Encryption” override any
other Content Manager disposition except “Log and Deliver.” Content Manager
filters may not apply if you use a Message Encryption rule in Content Manager.
Note: If an outbound message is quarantined, then released from quarantine, it
will be sent through normal mail delivery, not Message Encryption.
Reading Encrypted Messages
When the recipient opens an attachment containing an Inbox Delivery message, it
opens a local web browser.