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Security Type System
In computer science, a type system can be described as a syntactic framework which contains a set of rules that are used to assign a type property (int, boolean, char etc.) to various components of a computer program, such as variables or functions. A security type system works in a similar way, only with a main focus on the security of the computer program, through information flow control. Thus, the various components of the program are assigned security types, or labels. The aim of a such system is to ultimately be able to verify that a given program conforms to the type system rules and satisfies non-interference. Security type systems is one of many security techniques used in the field of language-based security, and is tightly connected to information flow and information flow policies. In simple terms, a security type system can be used to detect if there exists any kind of violation of ''confidentiality'' or ''integrity'' in a program, i.e. the programmer wants to detect i ...
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Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ...
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Type System
In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a ''type'' (for example, integer, floating point, string) to every '' term'' (a word, phrase, or other set of symbols). Usually the terms are various language constructs of a computer program, such as variables, expressions, functions, or modules. A type system dictates the operations that can be performed on a term. For variables, the type system determines the allowed values of that term. Type systems formalize and enforce the otherwise implicit categories the programmer uses for algebraic data types, data structures, or other data types, such as "string", "array of float", "function returning boolean". Type systems are often specified as part of programming languages and built into interpreters and compilers, although the type system of a language can be extended by optional tools that perform added checks using the language's original type synta ...
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Information Flow
In discourse-based grammatical theory, information flow is any tracking of referential information by speakers. Information may be ''new,'' i.e., just introduced into the conversation''; given,'' i.e., already active in the speakers' consciousness; or ''old,'' i.e., no longer active. The various types of activation, and how these are defined, are model-dependent. Information flow affects grammatical structures such as: *Word order ( topic, focus, and afterthought constructions). *Active, passive, or middle voice. *Choice of deixis, such as articles; "medial" deictics such as Spanish ''ese'' and Japanese ''sore'' are generally determined by the familiarity of a referent rather than by physical distance. *Overtness of information, such as whether an argument of a verb is indicated by a lexical noun phrase, a pronoun, or not mentioned at all. * Clefting: Splitting a single clause into two clauses, each with its own verb, e.g. ‘The chicken turtles tasted like chicken.’ bec ...
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Non-interference (security)
Noninterference is a strict multilevel security policy model, first described by Goguen and Meseguer in 1982 and developed further in 1984. Introduction In simple terms, a computer is modeled as a machine with inputs and outputs. Inputs and outputs are classified as either ''low'' (low sensitivity, not highly classified) or ''high'' (sensitive, not to be viewed by uncleared individuals). A computer has the noninterference property if and only if any sequence of low inputs will produce the same low outputs, regardless of what the high level inputs are. That is, if a low (uncleared) user is working on the machine, it will respond in exactly the same manner (on the low outputs) whether or not a high (cleared) user is working with sensitive data. The low user will not be able to acquire any information about the activities (if any) of the high user. Formal expression Let M be a memory configuration, and let M_\text and M_H be the projection of the memory M to the low and high parts, ...
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Language-based Security
In computer science, language-based security (LBS) is a set of techniques that may be used to strengthen the security of applications on a high level by using the properties of programming languages. LBS is considered to enforce computer security on an application-level, making it possible to prevent vulnerabilities which traditional operating system security is unable to handle. Software applications are typically specified and implemented in certain programming languages, and in order to protect against attacks, flaws and bugs an application's source code might be vulnerable to, there is a need for application-level security; security evaluating the applications behavior with respect to the programming language. This area is generally known as language-based security. Motivation The use of large software systems, such as SCADA, is taking place all around the world and computer systems constitute the core of many infrastructures. The society relies greatly on infrastructure su ...
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Information Flow Policy Confidentiality Lattice
Information is an abstract concept that refers to something which has the power to inform. At the most fundamental level, it pertains to the interpretation (perhaps formally) of that which may be sensed, or their abstractions. Any natural process that is not completely random and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artifacts such as analogue signals, poems, pictures, music or other sounds, and currents convey information in a more continuous form. Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation. The concept of ''information'' is relevant or connected to various concepts, including constraint, communication, control, data, form, education, knowledge, meaning, understanding, mental stimuli, pattern, perception, proposition, representation, and en ...
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Hasse Diagram
In order theory, a Hasse diagram (; ) is a type of mathematical diagram used to represent a finite partially ordered set, in the form of a drawing of its transitive reduction. Concretely, for a partially ordered set (S,\le) one represents each element of S as a vertex in the plane and draws a line segment or curve that goes ''upward'' from one vertex x to another vertex y whenever y covers x (that is, whenever x\ne y, x\le y and there is no z distinct from x and y with x\le z\le y). These curves may cross each other but must not touch any vertices other than their endpoints. Such a diagram, with labeled vertices, uniquely determines its partial order. Hasse diagrams are named after Helmut Hasse (1898–1979); according to Garrett Birkhoff, they are so called because of the effective use Hasse made of them. However, Hasse was not the first to use these diagrams. One example that predates Hasse can be found in an 1895 work by Henri Gustave Vogt. Although Hasse diagrams were orig ...
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Lattice (order)
A lattice is an abstract structure studied in the mathematical subdisciplines of order theory and abstract algebra. It consists of a partially ordered set in which every pair of elements has a unique supremum (also called a least upper bound or join (mathematics), join) and a unique infimum (also called a greatest lower bound or meet (mathematics), meet). An example is given by the power set of a set, partially ordered by Subset, inclusion, for which the supremum is the Union (set theory), union and the infimum is the Intersection (set theory), intersection. Another example is given by the natural numbers, partially ordered by divisibility, for which the supremum is the least common multiple and the infimum is the greatest common divisor. Lattices can also be characterized as algebraic structures satisfying certain axiomatic Identity (mathematics), identities. Since the two definitions are equivalent, lattice theory draws on both order theory and universal algebra. Semilatti ...
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Computer Security
Computer security (also cybersecurity, digital security, or information technology (IT) security) is a subdiscipline within the field of information security. It consists of the protection of computer software, systems and computer network, networks from Threat (security), threats that can lead to unauthorized information disclosure, theft or damage to computer hardware, hardware, software, or Data (computing), data, as well as from the disruption or misdirection of the Service (economics), services they provide. The significance of the field stems from the expanded reliance on computer systems, the Internet, and wireless network standards. Its importance is further amplified by the growth of smart devices, including smartphones, televisions, and the various devices that constitute the Internet of things (IoT). Cybersecurity has emerged as one of the most significant new challenges facing the contemporary world, due to both the complexity of information systems and the societi ...
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