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针对多等级架构细化中安全属性(即无干扰属性)保持的问题,提出一个细化函数和若干细化规则。通过细化函数将安全域分解为若干子安全域,通过若干细化规则限定子安全域与其他安全域以及子安全域间需要满足的关系。使用四个定理对细化后的架构或者策略进行形式化的描述和分析表明,细化后的架构或者策略仍然保持原架构或者策略的安全属性(即无干扰属性)。 相似文献
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We address the question of typing noninterference (NI) in the calculus CCS, in such a way that Milner's translation into CCS of a standard parallel imperative language preserves both an existing NI property and the associated type system. Recently, Focardi, Rossi and Sabelfeld have shown that a variant of Milner's translation, restricted to the sequential fragment of the language, maps a time-sensitive NI property to that of Persistent Bisimulation-based Non Deducibility on Compositions (PBNDC) on CCS. However, since CCS was not equipped with a type system, the question of whether the translation preserves types could not be addressed. We extend Focardi, Rossi and Sabelfeld's result by showing that a slightly simpler variant of Milner's translation preserves a time-insensitive NI property on the full parallel language, by mapping it again to PBNDC. As a by-product, we formalise a folklore result, namely that Milner's translation preserves a behavioural equivalence on programs. We present a simple type system ensuring PBNDC on CCS, inspired by existing type systems for the π-calculus. Unfortunately, this type system as it stands is too restrictive to grant the expected type preservation result. We sketch a solution to overcome this problem. 相似文献