Sharing data with client-side encryption requires key management. Selecting an appropriate key management protocol for a given scenario is hard, since the interdependency between scenario parameters and the resource consumption of a protocol is often only known for artificial, simplified scenarios. In this paper, we explore the resource consumption of systems that offer sharing of encrypted data within real-world scenarios, which are typically complex and determined by many parameters. For this purpose, we first collect empirical data that represents real-world scenarios by monitoring large-scale services within our organization. We then use this data to parameterize a resource consumption model that is based on the key graph generated by each key management protocol. The preliminary simulation runs we did so far indicate that this key-graph based model can be used to estimate the resource consumption of real-world systems for sharing encrypted data.