RTEF-PP: A Robust Trust Evaluation Framework with Privacy Protection for Cloud Services Providers

The trust problem of Cloud Services Providers (CSPs) has become one of the most challenging issues for cloud computing. To build trust between Cloud Clients (CCs) and CSPs, a large number of trust evaluation frameworks have been proposed. Most of these trust evaluation frameworks collect and process evidence data such as the feedback and the preferences from CCs. However, evidence data may reveal the CCs’ privacy. So far there are very few trust frameworks study on the privacy protection of CCs. In addition, when the number of malicious CCs’ feedback increases, the accuracy of existing frameworks is greatly reduced. This paper proposes a robust trust evaluation framework RTEF-PP, which uses differential privacy to protect CCs’ privacy. Furthermore, RTEF-PP uses the Euclidean distances between the monitored QoS values and CCs’ feedback to detect malicious CCs’ feedback ratings, and is not affected by the number of malicious CCs’ feedback rating. Experimental results show that RTEF-PP is reliable and will not be affected by the number of malicious CCs’ feedback rating.