Tag Archives: capability

Computer Security Breaches Are Preventable

Security system breaches resulting in exposure of large quantities of sensitive information have become increasingly common. As data-hungry enterprises aggregate larger and larger caches of sensitive information, the damage from the inevitable breaches becomes more significant and far-reaching. Is there something fundamentally wrong with the design of our security systems? Can these risks be mitigated? […]

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Distributed Security

Within a single address-space, the capability-security properties of actor references are guaranteed by the actor run-time. Memory-safe implementations of actor languages ensure that actor references cannot be forged. Having a reference to an actor means you have permission to send it a message. A single machine may host multiple independent actor address-spaces, each of which […]

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Implementing Actors in JavaScript

JavaScript does not exactly have an ideal semantic model for implementing Actors. Execution is single-threaded and sequential. Most objects are mutable by default. However, it has the advantage of being the most available and widely used computer language, so it seems worthwhile to show how actors can be used in this environment. Asynchronous Programming JavaScript […]

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Futures and Capabilities

In the Actor Model, concurrency is the default. Sequencing must by arranged explicitly. An important case of sequencing occurs when there is a data dependency between different parts of a system. One part produces a value that another part needs to perform its function. One mechanism for sequencing data-dependent operations is to create a Future. […]

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Deconstructing the Actor Model

The Actor Model of Computation, as defined by Carl Hewitt [1] and elaborated by Gul Agha [2], defines three primitive operations. These operations are “Send”, “Create” and “Become”. The “Send” operation transmits an asynchronous message to a known receiver. The “Create” operation constructs a new actor with a specified initial behavior. The “Become” operation defines […]

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