Suitability of obfuscation methods for different categories of context

Context aware services need context of a certain quality to provide their services. The quality of context can be described using the Quality of Context (QoC) concept. There are five parameters, or dimensions, to describe the QoC: precision, freshness, temporal resolution, spatial resolution and probability of correctness. There is a relation between QoC and privacy sensitivity, because if the QoC is higher, the privacy sensitivity is typically higher. To influence the privacy sensitivity, context can be obfuscated in one or more QoC dimensions. We identify different categories of context. For each category the importance of the QoC parameters on the privacy sensitivity is examined. Obfuscating the probability of correctness gives the user plausible deniability and reduces the privacy sensitivity of context in all categories. Furthermore, obfuscating context in the precision dimension reduces the QoC in all categories.