An advanced gray image encryption scheme by using discrete logarithm with logistic and HEH64 chaotic functions

In recent days chaos based image encryption is going through under research and implementation. Some chaos based algorithms are working well and resists many type of crypto analysis attacks, but it takes lot of time for encryption and decryption. Some of chaos based algorithms are very fast but their strength to resist attack is questionable. So these have motivated us to design a crypto system which will take less amount of time for encryption and decryption and it should resist all type of crypto analysis attacks. In this paper we have developed an advanced image encryption scheme by using block based randomization and chaos system. Here we discuss a block based transformation algorithm in which image is divided in to number of blocks. Then these blocks are transformed before going through a chaos based encryption process. At the receiver side after decryption, these blocks are re- transformed in to their original position. The main advantage of this approach is that it reproduces the original image with no loss of information during the encryption and decryption process in a reasonable amount of time, and due to sensitive chaos system becomes it more secure and reliable over the network.