The recent advances in information theory and networking have significantly modified the way to disseminate data in wireless sensor networks (WSNs): aggregation, network coding or rateless codes. These new paradigms of dissemination create new threats for security such as pollution attacks. These attacks exploit the difficulty to protect data integrity in those contexts. In this paper, we consider the particular case of xor network coding. We compare the different strategies based on message authentication codes algorithms (MACs) to thwart these attacks. We emphasize the advantages of universal hash functions (UHFs) in terms of flexibility and efficiency. These schemes reduce the energy consumption by 42% and 68% (according to the used protocol) for the relaying nodes over those based on classical cryptographic primitives without any loss in security. The key feature of the UHFs considered here is their homomorphic property h(x1 ⊕ x2 ) = h(x1 ) ⊕ h(x2 ). These homomorphic MACs offer more possibilities for the relying nodes than the classical cryptographic ones: the detection time of a pollution attack can be adjusted to preserve the nodes energy. Moreover, they can be computed with the low resources of a sensor.