Google Message Encryption Administration Guide - Manual (Page 51)

52 Postini Encryption Services Administration Guide
• Mozilla Firefox 1.06 or later
• Netscape Navigator 8.0 or later
Inbox Delivery also requires cookies and JavaScript support in the browser.
What privacy settings are needed?
For supported browsers, use the default security settings or lower.
Are secure messages ever sent directly to the recipient?
If both the sender and the recipient are signed up with Message Encryption,
messages are sent directly to the recipient’s mail server. Messages are encrypted
on every step of transmission.
Notifications are being quarantined as spam
If Message Encryption notifications sent to you are being quarantined as spam,
add
@secure.psmtp.com to the list of approved senders for the email security
service, as well as your firewall or server.