Providing efficient data aggregation while preserving data privacy in wireless sensor networks (WSNs) is a challenging problem. Existing security schemes either incur high communication and computational overheads or simply fail to counter attacks when nodes are compromised. In this paper, we present a multidimensional privacy preserving data aggregation scheme for WSNs which is efficient and provides strong security. The scheme not only provides efficient countermeasure against passive and active privacy compromising attacks, coalition attacks from malicious base station and captured sensor nodes, but also is robust to data loss. In addition, the proposed scheme provides data aggregation with constant communication overheads, so that the transmission cost can be significantly reduced which makes it suitable to be used in large scale WSNs. To the best of our knowledge, our scheme is the first one that addresses the privacy and efficiency issues in WSNs all at once.