Language-based security

Abstract: Current standard security practices do not provide substantial assurance that the end-to-end behavior of a computing system satisfies important security policies such as confidentiality. An end-to-end confidentiality policy might assert that secret input data cannot be inferred by an attacker through the attacker's observations of system output; this policy regulates information flow. Conventional security mechanisms such as access control and encryption do not directly address the enforcement of information-flow policies. Previously, a promising new approach has been developed: the use of programming-language techniques for specifying and enforcing information-flow policies. In this paper, we survey the past three decades of research on information-flow security, particularly focusing on work that uses static program analysis to enforce information-flow policies. We give a structured view of work in the area and identify some important open challenges.

Abstract: This paper investigates mechanisms that guarantee secure information flow in a computer system. These mechanisms are examined within a mathematical framework suitable for formulating the requirements of secure information flow among security classes. The central component of the model is a lattice structure derived from the security classes and justified by the semantics of information flow. The lattice properties permit concise formulations of the security requirements of different existing systems and facilitate the construction of mechanisms that enforce security. The model provides a unifying view of all systems that restrict information flow, enables a classification of them according to security objectives, and suggests some new approaches. It also leads to the construction of automatic program certification mechanisms for verifying the secure flow of information through a program.

Abstract: onfining a program during its execution so that it cannot transmit information to any other program except its caller. A set of examples attempts to stake out the boundaries of the problem. Necessary conditions for a solution are stated and informally justified.

Abstract: A promising technique for protecting privacy and integrity of sensitive data is to statically check information flow within programs that manipulate the data. While previous work has proposed programming language extensions to allow this static checking, the resulting languages are too restrictive for practical use and have not been implemented. In this paper, we describe the new language JFlow, an extension to the Java language that adds statically-checked information flow annotations. JFlow provides several new features that make information flow checking more flexible and convenient than in previous models: a decentralized label model, label polymorphism, run-time label checking, and automatic label inference. JFlow also supports many language features that have never been integrated successfully with static information flow control, including objects, subclassing, dynamic type tests, access control, and exceptions. This paper defines the JFlow language and presents formal rules that are used to check JFlow programs for correctness. Because most checking is static, there is little code space, data space, or run-time overhead in the JFlow implementation.