2.2.5.2 S/MIME Certificate

The userSMIMECertificate attribute contains certificates in the format specified in [RFC2798] or certificates in the format defined for the PidTagUserX509Certificate property, as specified in [MS-OXOABK] section 2.2.4.36. If available, this attribute SHOULD be preferred over the userCertificate attribute for S/MIME (Secure/Multipurpose Internet Mail Extensions) applications.