Architectural support for trust models in decentralized applications

Abstract

Decentralized applications are composed of distributed entities that directly interact with each other and make local autonomous decisions in the absence of a centralized coordinating authority. Such decentralized applications, where entities can join and leave the system at any time, are particularly susceptible to the attacks of malicious entities. Each entity therefore requires protective measures to safeguard itself against these entities. Trust management solutions serve to provide effective protective measures against such malicious attacks. Trust relationships help an entity model and evaluate its confidence in other entities towards securing itself. Trust management is, thus, both an essential and intrinsic ingredient of decentralized applications. However, research in trust management has not focused on how trust models can be composed into a decentralized architecture. The PACE architectural style, described previously [21], provides structured and detailed guidance on the assimilation of trust models into a decentralized entity's architecture. In this paper, we describe our experiments with incorporating four different reputation-based trust models into a decentralized application using the PACE architectural style. Our observations lead us to conclude that PACE not only provides an effective and easy way to integrate trust management into decentralized applications, but also facilitates reuse while supporting different types of trust models. Additionally, PACE serves as a suitable platform to aid the evaluation and comparison of trust models in a fixed setting towards providing a way to choose an appropriate model for the setting.

Using traits of web macro scripts to predict reuse

“…For instance, collaborative filtering makes recommendations of the form, "People like you found the following components to be helpful" [18][22], which requires that some programmers try a certain piece of code before it can be recommended to other programmers. There is one approach that might apply to end-user scripting: predicting that code will have high reusability if the author previously created code that was reused, indicating that the author has high expertise [33]. Such a model's information requirements are not very restrictive, since a component's reusability can be predicted even if it has never been reused, as long as someone previously tried to reuse one of the programmer's other components.…”

Predicting reuse of end-user web macro scripts

“…There is one approach that might apply to end-user scripting: predicting that code will have high reusability if the author previously created code that was reused, indicating that the author has high expertise [18]. This approach's information requirements are not very restrictive, as a component's reusability can be predicted even if it has never been reused, as long as someone previously tried to reuse one of the programmer's other components.…”

Characterizing reusability of end-user web macro scripts

“…Some systems address this limitation by tracking the reputation of component creators, rather than just components themselves [20]. We consider several characteristics that might relate to script authors' expertise.…”

“…Selecting a longer interval reduces the number of scripts whose observation interval fell within the 6 months of available logs. Selecting half of the log period as the observation interval resulted in few cases (20) of erroneously ruling a script as not-reused, yet it provided over 900 scripts for study.…”