Policy-enforced TLS provides

Emerging regulations and best practices are encouraging companies to encrypt email messages that contain sensitive and confidential information. Policy-enforced TLS employs transport layer security to automatically encrypt email connections between businesses. Google security service, powered by Postini, integrates strong TLS encryption with policy-based management so you can control and ensure which messages are delivered over encrypted connections.

Policy-enforced TLS provides

Enforced server-to-server encryption, prevents un-encrypted emails from being sent .
Automatic processing, with no additional integration .
Zero impact to recipient–does not require software or key installation .
Secure communications with regular business partners without the cost of virtual private networks and leased lines .
Simple administration via the Administrative Console .

As an on-demand service, Policy-enforced TLS requires no new software, hardware, or maintenance. Administrators can easily and dynamically set policies based on users, content, or recipients.