MPEG 2 transparent scrambling algorithm based on DCT domain

A new transparent scrambling algorithm was proposed, which performs an arbitrarily degraded view of the decoded picture by encrypting DCT coefficients of the Intra frames. Through the prediction, the effects of encrypting Intra frames can be spread into the whole video sequence. This technique overcomes the drawback of scrambling pixel in spatial domain, which reduces the compressed efficiency of the encoder. Through many experiments, it is proved that the new algorithm can achieve good scrambling result and can be applied into the broadcast systems, such as DVB/ATSC, which use MPEG-2 as compression standard.