RAISE THE STRENGTH OF CRYPTOSYSTEM USING VARIETY EFFECTS

Nowadays, images became one of the most types of transmitted data through Internet. Some of these images carry secret information, therefore having an effective cryptosystem for hiding the information inside these images become an urgent need. Many traditional encryption methods are unable to achieve a high degree of protection for information. This paper presents nontraditional method for image encryption through applying substitution and transposition operations in different ways on both key and data. Series of (Linear and Circular), (Left, Right, Up and Down) rotation operations on (Bits and Bytes) of key and data are applied to make good confusion effects in the data. Moreover, XOR Boolean operations also applied on the key and data to make diffusion effects in the data. These two types of operations will produce a large set of keys. Using this large number of different keys in encrypting image will raise the strength of the encryption system used and achieve a high degree of protection for image. To test the security degree and performance of the encryption system, the system has been applied using different images and analyzing the results key space, key sensitivity, and statistical analysis and other criteria. From these tests, we can conclude that the encryption system can be used effectively to protect digital images