The AuthenticationLevel property specifies the minimum client authentication level required by this COM server. If NULL, ...

The AuthenticationLevel property specifies the minimum client authentication level required by this COM server. If NULL, the default values are used. Authentication levels include:
None - no authentication is performed.
Connect - authentication is performed only when the client establishes a relationship with the application.
Call - authentication is performed only at the beginning of each call when the application receives the request.
Packet - authentication is performed on all data received from the client.
PacketIntegrity - all the data transferred between client and application is authenticated and verified.
PacketPrivacy - The properties of the other authentication levels are used, and all data is encrypted.