A security model is provided in a transactional logging infrastructure that is arranged as a protected subsystem built on an underlying secure file system. Files in the underlying file system used by virtual log streams are protected from direct user writes, and are written-to only through the protected subsystem that is brokered by a machine-wide principal so that virtual log files sharing the same multiplexed physical log are kept secure from each other. Log file handles and user- and kernel-mode objects are exposed to log clients through interfaces using consistent security semantics for both dedicated and virtual logs. Log clients are agnostic of the underlying secure file system and can only manipulate file system containers—abstract objects that implement the physical log and used to virtualize the file system by normalizing input/output operations—by using the interfaces brokered by the principal in the protected subsystem.