Sierra
An OpenPrivacy Reputation Management Framework

Design

Sierra provides a reference implementation for the components of an OpenPrivacy Reputation Management Framework (RMF) resulting in a Reputation Management System. Based on Talon components, Sierra incorporates a high level of modularity and atomicity, resulting in a flexible fabric that will enable easy component upgrades as experience with the system grows.

In Sierra we use Talon as the Component mechanism. Talon acts as a kernel and serves/creates Component implementation instances. Sierra is configured with a file (sierra.properties) which has Component deployment descriptors that have settings for RCEs, Nym Providers, Network communications, etc.

Each Component is a java interface which extends talon.Component. When a new technology (new Crypto provider, new Database layer, etc) needs to be added a bridge is written between Sierra and the new technology. If we wanted to add an Advogato Trust Metric to Sierra we would write a new class named AdvogatoRCE which implemented RCE. This builds a one to many relationship to all new RCEs.

Each Component can be obtained from an application as an Object instance via talon.ComponentFactory. In order to obtain a component instance, Developers can either provide the ComponentFactory with an implementation name (AdvogatoRCE) or a handle name ("talon:///component-name/product/sierra/name/rce").

Generally the handle is used because it allows a developer to change implementations at runtime. For example if we wanted to change the default RCE to say a WeightedRCE (an RCE which answers with by averaging with weights) we would just have to modify the sierra.properties file and change the "talon:///component-name/product/sierra/name/rce" to point to the new WeightedRCE component implementation.

Sierra developers are encouraged to review the Talon project and its associated documentation.