Techniques are disclosed relating to computing security and privacy. In some embodiments, a computing device provides, to a service computing system, a service request that identifies an action and includes an anonymous identifier for a user of the computing device. The computing device receives, from the service computing system, a score request for a trustworthiness score indicative of the user's trustworthiness. In response to receiving the score request from the service computing system, the computing device provides information indicative of the user's identity to a scoring computing system and receives the trustworthiness score and a corresponding score signature from the scoring computing system. In response to receiving the score and the score signature from the scoring computing system, the computing device provides the score to the service computing system.