Advogato trust metric

The Advogato trust metric is one of the first proposed trust metric. It was created by Raph Levien. The goal is to be attack-resistant. It is described here.

Advogato is also the name of the web site (advogato.org) created by Raph Levien for testing his trust metric. Advogato web site is a community of Free Software developers.

Advogato community
Advogato (http://advogato.org) is an online community site dedicated to free software development, created by Raph Levien. Levien created Advogato also as a research testbed for testing his own attack-resistant trust metric, the Advogato trust metric. On Advogato users can certify each other on 4 different levels: Observer, Apprentice, Journeyer, and Master and the Advogato trust metric uses this information in order to assign to every user a certification level. The goal is to be attack-resistant, i.e. to reduce the impact of attackers.

Advogato trust metric
Advogato performs certification to three different levels: Apprentice, Journeyer, and Master. This is actually done by running the basic trust metric three times, using the "level" value in the certificate as a threshold. Thus, certification of Apprentices is computed using all certificates, while Master is computed using Master certificates only.

The computation of the trust metric is performed relative to a "seed" of trusted accounts. At the time of this writing (22 Feb 2000), the seed consists of raph, miguel, federico, and alan.

The core of the trust metric is a network flow operation. Informally, if there is a rich web of interconnections, flow reaches almost all the nodes. However, only a few accounts would be accepted from a large nest of bogus accounts, as long as there are only a few certificates from the "good" web to the bogus accounts. Those certificates represent a bottleneck in the network flow.

The complete description is available on advogato site.

An implementation of the trust metric in python is available in pymmetry and another one in net_flow Python wrapper. Both of them are in our code.

Advogato dataset
See Advogato dataset.

Papers analyzing Advogato dataset
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 * Trustlet, Open Research on Trust Metrics
 * Bowling Alone and Trust Decline in Social Network Sites
 * Evaluation of the Iterative Multiplication Strategy for Trust Propagation in Pervasive Environments. Omar Hasan, Lionel Brunie, and Jean-Marc Pierson. ICPS 2009.