Russian term (edited): ���������� user mod

I think the meaning is this: The operating system intercepts all user calls that want to access the clipboard (typically this happens when you want to paste something into a document). It decides whether to permit access based on the caller's privileges and the level of security of the data in the clipboard (assigned by whoever put it there). Requires some system overhead, but the logic extends straightforwardly to other forms of shared file resources.