End user manage encryption per email?

Question

Is it possible for an end user to manage email encryption S/MIME or PGP? 
 Like adding a keyword in the email title like: 
 
 {encrypt} - force encryption. Email will not be delivered by UTM if email cannot be encrypted (lack of public key) 
 {clear} -do not encrypt, even if Sophos UTM has a public key to the recipient.

BAlfson · Accepted Answer

Not that I know of, Erik. If you discover that it is, please post back here. 
 Cheers - Bob

DouglasFoster · Answer

What you want to do is fully supported in UTM: 
 
 If UTM has OpenPGP or SMIME keys for encrypting to the recipient, outgoing messages are encrypted automatically. 
 For everyone else, you have two choices, which will trigger SPX encryption: 
 
 Deploy the Outlook plug-in, which allows the user to trigger SPX encryption by clicking a button during message creation. 
 Create a custom Data Protection rule to trigger SPX encryption when a specific expression is detected, then teach your users to use this expression. This technique has the advantage of working with webmail and phone-based mail clients. NOTE: The Data Protection rules are applied to the raw content of a message, so you need to use a phrase or a delimited keyword to avoid false positives. Your example should work well, as it is unlikely to appear in a message for other reasons.

There is no version of your CLEAR keyword, as it is generally not necessary. Some client-based OpenPGP implementations provide an Outlook plug-in which allows the user to disable encryption for a particular message. In UTM, the only way to disable OpenPGP or SMIME encryption is to delete the recipient's public key.