White Paper


   Reptile (SCDS)
   User Content License



Reputations and Reputation Management Concepts

Every agent within the OpenPrivacy system is based on the Reputation Management Framework (RMF) which provides the basis for secure, pseudonymous and distributed communities and other applications.

Sierra is our reference implementation of a Reputation Management Framework, and is the best place to look for more information.

Below are some pointers to further reading. (Please see the Definitions page for help with the terminology.)

from Platform (/platform.shtml):

Secure, Privacy-enhanced Reputation Facility

Reputations are the cornerstone to any virtual community. OpenPrivacy enables reputations to be used to enhance searching as well as to filter out unwanted information, all while maintaining complete user privacy. In addition, the reputation substrate supports the user to:
  • accumulate valuable reputation capital for shared profile information, ideas and publications without needing to divulge identity
  • annotate any object with machine-readable opinions (grafts), thus creating a general purpose and secure reputation facility
  • enable opt-in profile/reputation owner contact by third parties

from Requirements (/opr.shtml)

Reputations are first class objects, that can be applied to any entity within the OpenPrivacy system. In a sense, all objects derive from class Reputation. Reputations have several component parts, including:
  • Reference - the entity URI to which this reputation is attached
  • Identity - a unique URL (used for naming and assigning additional reputation)
  • Signature - the signature of the assigning party
Additional fields may exist that give additional information to the reputation:
  • Payload - one or more semantic names, types and/or values for this reputation
  • Ontology - provides semantic categorization for the payload
  • Nym - provides direct reference to assigner
  • creation date - date when this reputation was created
  • expiry date - date when this reputation is no longer valid
  • Eternity_checksum - persistent, time-stamped value that ensures non-repudiation (definition TBD)


  • Personalization and Reputation Management
  • Channels, articles and indeed all objects within the OpenPrivacy framework can be enhanced via the grafting of reputation objects. This provides a facility to provide feedback to the creation, delivery and presentation aspects of each object, as well as enabling threshold alerts and other advanced features.
  • Privacy and Nym Management
  • All reputation grafts (annotations of opinions and/or rankings) and subscription activities are made pseudonymously through a client-side "Primary Agent" - part of the peer-to-peer OpenPrivacy Reputation Management Framework. This Primary Agent creates and manages nyms for the user transparently, and enables the user to view, modify and/or delete reputation information whether stored locally or remotely.

    Additional reputation links:

  • In the reputation model, for each exchange, a server risks some amount of resources that is proportional to its trust that the result will be satisfactory. As a server's reputation grows, other nodes become more willing to make larger payments to it.
    The main difference between reputation-based trust systems and micropayment-based trust systems is that, in reputation-based trust systems, parties base their decisions in part on information provided by third parties.
  • Each Broker maintains its own local database of reputations for other Brokers, including a list of others with which it has done business and information about those transactions.
  • Reputation Manager ... will alert members about the hierarchy and ratings of other members, providing visitors with a way to sort high quality member-generated content from less useful contributions and highly-rated members from less highly-rated ones.
  • The goal of the trust metric is to accept as many valid accounts as possible, while also reducing the impact of attackers.
  • The whole area of digitally-authenticated reputations, and the "reputation capital" that accumulates or is affected by the opinions of others, is an area that combines economics, game theory, psychology, and expectations.

      OpenPrivacy satisfies one of the requirements for Broadcatch systems
       and supports the Principles of the Identity Commons

    Historical note: OpenPrivacy closed its virtual doors in May of 2002.
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