SCRAMBLE TRANSFORMING DEVICE AND INVERSE SCRAMBLE TRANSFORMING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a scramble transforming device, with which scramble processing can be performed by a simple method, concerning the scramble transforming device for enciphering the bit stream of compressed data group generated by encoding an image. SOLUTION: A scramble transforming device A performs scramble transformation by arbitrarily rearranging the bit stream sent from an encoder 10. For example, slice layers as hierarchical units in a certain picture layer are rearranged. This rearrangement is performed according to a cryptographic key stored in a cryptographic key storage part 40 and as the cryptographic keys, there are 'hierarchy of rearrangement', 'range of rearrangement' and 'order of rearrangement'. Corresponding to an 'image pattern' to be generated corresponding to whether data are hierarchical units or not and these 'hierarchy of rearrangement' and 'range of rearrangement', the 'order of rearrangement' is selected and according to that order, rearrangement is performed.