Home and Building Automation Systems are becoming more and more popular these days. While they increase the comfort of living, they may also leak private information such as user presence to passive observers. In this paper we investigate approaches for the generation of dummy traffic in Home Automation Systems (HASs).We discuss fundamental requirements and their impact as well as two concrete dummy traffic generation algorithms.We measure the impact of Constant- Rate Dummy Traffic (CRDT) on the responsiveness and energy efficiency of Home Automation Systems. As an alternative, we present the Naive Exponential Dummies (NED) generation scheme in which the balance between privacy guarantees and energy efficiency can be arbitrarily moved. We formally prove its privacy guarantees and evaluate it against realistic sample data.
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