Dynamics, robustness and fragility of trust

Dusko Pavlovic ( Oxford University Computing Laboratory )

I present a model of the process of trust building that suggests that trust is like money: the rich get richer. The proviso is that the cheaters do not wait for too long, on the average, with their deceit. The model explains the results of some recent empiric studies, pointing to a remarkable phenomenon of *adverse selection*: a greater percentage of unreliable or malicious web merchants are found among those with certain (most popular) types of trust certificates, then among those without. While some such findings can be attributed to a lack of diligence, and even to conflicts of interest in trust authorities, the model suggests that the public trust networks would remain attractive targets for spoofing even if trust authorities were perfectly diligent. If the time permits, I shall discuss some ways to decrease this vulnerability, and some problems for exploration.