In an embodiment, a first device detects a first interaction between the first device and a second device. The first device assigns a first rating of the first interaction. The first device calculates an internal trust for the second device based on the first rating and a first time since the occurrence of the first interaction. The first device receives trust data from a third device. The first device calculates a community trust for the second device based on the trust data and an internal trust that the first device has for the third device. The first device calculates a total trust that the first device has for the second device based on the community trust and the internal trust that the first device has for the second device. If the total trust is less than a minimum threshold, the first device disallows a second interaction.