An apparatus and method provides one or more controlled, dynamically loaded, modular, cryptographic fillers. Fillers may be loaded by a single loader, multiple independent loaders, or nested loaders. Loaders may be adapted to load other loaders, within cryptographic controls extant and applicable thereto. Integration into a base executable having one or more slots, minimizes, controls, and links the interface between the fillers and base executables. The filler may itself operate recursively to load another filler in nested operations, whether or not the fillers are in nested relation to one another. An ability of any filler to be loaded may be controlled by the base executable verifying the integrity, authorization, or both for any filler. The base executable may rely on an integrated loader to control loading and linking of fillers and submodules. A policy may limit each module function, access, and potential for modification or substitution. Dynamically loaded modules (loaders, other fillers, and submodules thereof), typically represent a relatively small portion of the overall coding required by the base executable, and may provide strong controls limiting integration by providing access that is nested, layered, or both between modules excluding direct access to or by them from the base executable or supported applications.