Network coding techniques such as fountain codes are a promising way to disseminate large bulks of data in a multicast manner over an unreliable medium. In this work we investigate how to conceal such an encoded data stream on its way to numerous receivers with a minimum investment. Compared to conventional 'encrypt - encode/decode - decrypt' approaches, our solution is preferable for two reasons: First, it causes less CPU investment for encryption and decryption proportional to the ratio of the payload length to the signaling data length. Second, besides obfuscating the payload data from an eavesdropper, we hide the coding information from an eavesdropper. We evaluate the approach with respect to its application to various data types like MPEG-2 video streams and Java bytecode.