—The recent interest in outsourcing IT services onto the cloud raises two main concerns: security and cost. One task that could be outsourced is data mining. In VLDB 2007, Wong et al. propose an approach for outsourcing association rule mining [1]. Their approach maps a set of real items into a set of pseudo items, then maps each transaction nondeterministically. This paper, analyzes both the security and costs associated with outsourcing association rule mining. We show how to break the encoding scheme from [1] without using context specific information and reduce the security to a one-toone mapping. We present a stricter notion of security than used in [1], and then consider the practicality of outsourcing association rule mining. Our results indicate that outsourcing association rule mining may not be practical, if the data owner is concerned with data confidentiality. Keywords-association rule mining, outsourcing, security