With the fast adoption of Services Computing, even more driven by the emergence of the Cloud, the need to ensure accountability for quality of service (QoS) for servicebased systems/services has reached a critical level. This need has triggered numerous researches in the fields of trust, reputation and provenance. Most of the researches on trust and reputation have focused on their evaluation or computation. In case of provenance they have tried to track down how the service has processed and produced data during its execution. If some of them have investigated credibility models and mechanisms, only few have looked into the way reputation information is produced. In this paper we propose an innovative design for the evaluation of feedback authenticity and credibility by considering the feedback's provenance. This innovative consideration brings up a new level of security and trust in Services Computing, by fighting against malicious feedback and reducing the impact of irrelevant one.