Providing software integrity using type managers

The authors consider the protection of software development objects, including design specifications, program text, executables, test results and documentation, from both accidental and malicious modifications. An integrity policy based on the authors´ interpretation of the D. Clark and D. Wilson (1987) model is defined and mechanisms to enforce the policy are described. Emphasis is on software mechanisms which can be implemented on current computer systems. The approach is based on capabilities that limit the potential damage of undetected Trojan horses in development tools, and type managers that control access to software objects