Google Message Encryption Administration Guide - Manual (Page 26)

Message Encryption, Portal Delivery 27
1. Sender to Email Security Service
Your outbound email is routed through the email protection service. To assure that
your email is secure, set up TLS on your mail server and transmit only encrypted
messages to the email protection service. Confidential messages are sent to
Secure Portal. Other messages are delivered directly to the recipient’s mail
server. You can send messages up to 10MB in size through Message Encryption.
Larger messages will be bounced with a 554 error message.
2. Email Security Service to Secure Portal
Messages routed to Portal Delivery are sent securely by TLS to the Secure Portal.
Because your secure messages may be stored in the Secure Portal for a period of
weeks, your mail is stored using 168-bit encryption. This is more secure than
industry-standard 128-bit encryption.
3. Notification to Recipient
Portal Delivery sends a notification that informs the recipient of the message. The
notification includes a link to set up an account within the Secure Portal.
4. Recipient to Secure Portal
Using HTTPS on a standard web browser, the recipient can view, download, and
reply to the message in the Secure Portal. Messages remain in the Secure Portal
for 14 days. The Secure Portal is a branded web interface that secured by
password. In the Secure Portal, recipients can read, download, and reply to
confidential messages.