Emerging practical schemes indicate that algebraic mixing of different packets by means of random linear network coding can increase the throughput and robustness of streaming services over wireless networks. However, concerns with the security of streaming multimedia, in particular when only a subset of the users in the network is entitled to the highest quality, have uncovered the need for a network coding scheme capable of ensuring different levels of confidentiality under stringent complexity requirements. We consider schemes which exploit the algebraic structure of network coding to achieve the dual goal of hierarchical fidelity levels and efficient security. The key idea is to limit the encryption operations to the encoding vector, in combination with multi-resolution multimedia coding.