This document describes how to preset the expiration time for secure envelopes that are generated from a Cisco Email Security Appliance (ESA) that implements Cisco Registered Envelope Service (CRES).
Can I preset the expiration time of secure envelopes that are generated from a Cisco Email Security Appliance that uses CRES?
An option cannot be found in the Cisco ESA in order to preset the expiration time of secure envelopes.
Add a custom header into the outbound mail prior to encryption.
In order to configure a message so that it expires 24 hours after you send it, insert this header into the message:
The recipient can open and view the content of the encrypted message during the 24-hour period after you send it. After that, the Registered Envelope displays a message which indicates that the envelope has expired.