IT services realized within cloud environments often suffer from a lack of transparency. On the one hand this opacity with respect to operational practices protects business secrets of a cloud provider. On the other hand, if services from critical infrastructures run within clouds this opacity becomes a severe problem, e.g., for a later root cause analysis in case of failures. This paper presents approaches for auditing the mapping of virtual resources to physical resources while preserving corporate confidentiality of the cloud providers. We also make sure that the resulting auditing information is useful for a later root cause analysis. Our research concludes that statistical binding and computational hiding commitment schemes are a suitable solution. Moreover, our approach enables a trusted third party to perform audits on behalf of tenants.