West, A.G., Aviv, A.J., Chang, J., Prabhu, V.S., Blaze, M., Kannan, S., Lee, 
I., Smith, J.M., & Sokolsky, O. (2009). QuanTM: A Quantitative Trust 
Management System. In EUROSEC 2009, pp. 28-35. Nuremburg, Germany.


Abstract: Quantitative Trust Management (QTM) provides a dynamic 
interpretation of authorization policies for access control decisions based 
on upon evolving reputations of the entities involved. QuanTM, a QTM system,
selectively combines elements from trust management and reputation management
to create a novel method for policy evaluation. Trust management, while 
effective in managing access with delegated credentials (as in PolicyMaker 
and KeyNote), needs greater flexibility in handling situations of partial 
trust. Reputation management provides a means to quantify trust, but lacks
delegation and policy enforcement.

This paper reports on QuanTM's design decisions and novel policy evaluation
procedure. A representation of quantified trust relationships, the trust 
dependency graph, and a sample QuanTM application specific to the KeyNote 
trust management language, are also proposed.