May Testing, Non-interference, and Compositionality

This paper uses CSP to introduce a characterisation of non interference in terms of the deductions that may be made about high level processes by low level tests May testing yields classic noninference and has a concise formulation in CSP It is preserved by a wider range of composition oper ators than are normally considered in the context of non interference It turns out that the extensive list of compositionality theorems in our case can be used to derive the cases generally considered The CSP character isation of may non interference also permits some attractive and simple compositionality proofs