Secure selective encryption of compressed audio

The large scale use of multimedia data like compressed audio necessitates the need for its secure distribution without affecting the quality. In this paper a more secure and less complex method is proposed where a part of the MP3 bit stream is encrypted with multiple keys generated from a single seed using a modified key stream generator based on LFSR and Division Modulo Circuit. The throughput of the stream cipher generated using modified LFSR key stream generator is much higher than the normal LFSR based structures of the same key length. Security is achieved in this by using Boolean functions to combine the state bits of the LFSR keystream generator similar to a non linear filter generator. Also this algorithm is computationally simple compared to the similar existing algorithms. Partially encrypted audio data can be distributed freely for evaluation and may be decrypted using the key to get full quality.