Exchange Server question
 

I have this problem I need to solve from a buddy of mine. Any help would be appreciated:

There should be 3 types of S/MIME emails:
- signed
- encrypted
- signed and encrypted.

How an S/MIME email can be distinguished from a standard (i.e. un-signed, un-encrypted) message?

Is S/MIME information captured in the header of the message? (If so, would anyone have samples of what each of the 3 distinguishing characteristics look like?)

Thanks