I am currently writing an add-in that integrates Outlook with a third party system. This is quite a niche case I understand, but I am running into a very tricky problem with Outlooks security.
Using the Registry setting: HKCU/Software/Policies/outlook/16.0/security/externalsmime = 2 or 0 (1 makes encrypted emails not open correctly in Outlook), we find that any attempt to access the emails information (I.e. msg.EntryId) results in the following exception.
System.Runtime.InteropServices.COMException (0xB5B90020): Your Digital ID name cannot be found by the underlying security system
However if the user has entered their SmartCard PIN (By opening an encrypted email for example) then we have access to the message.
So my question is, do we have any programmatic method of launching the PIN entry dialog if the PIN cache is empty?