Specifies attributes for a signed message.
- macOS 10.5+
The CMSEncoder reference returned by the
Attribute flags as defined in
A result code. See Security Framework Result Codes.
Attributes are optional for signed messages. They are not used for other types of CMS messages. The use of attributes is described in section 2.5 of the S/MIME 3.1 specification.
If you do call this function, you must call it before the first call to the