If the SMIMECapabilities attribute (1.2.840.1135220.127.116.11) is found, the S/MIME Capabilities (typically encryption preferences) are decoded and listed. S/MIME capable email clients use the SMIMECapabilities attribute in received signed email messages to know the (ordered) encryption preferences of the sender.
Other Authenticated Attributes are not decoded in this utility, but can be easily handled the same way.
This utility uses P/Invoke to CryptoAPI functions:
SMIMECapabilities sent by various S/MIME email clients
Michel I. Gallant