Abstract:

An algorithm of RGB image encryption and compression based on the technique of generalized knight's tour scrambling encryption is proposed by considering from the view of ensuring the confidential image security and transmission efficiency. In this algorithm the YCbCr layers of original image are divided into 8×8 blocks respectively after image pattern turned from RGB to YCbCr, then every block is transformed by DCT to build 3dimensional chessboard,And the 3dimensional chessboard is encrypted by the principle of generalized knight's tour, Finally the encrypted and compressed image could be gained by JPEG compression. Experimental results and analysis show that the algorithm is low impact on image compression capability, it gets higher compression efficiency in content of some degree of safety.

Key words: RGB image encryption;generalized knight’s tour scrambling;generalized knight’s tour;blocking