Encryption and decryption of bitmap images via blowfish and pseudo triple des block cipher algorithms in distributed systems

Abstract

In this experience, Blowfish and Simulated Triple Data Encryption Standard (ST-DES) are two block cipher algorithms which are used for image encryption on each computer and java serialization technique is used to transmit encrypted images across a network connection link in binary form. Therefore, if intruders over the network try to tap into my communication, they cannot understand the information which is being transmitted. Different types of Bitmap images are encrypted with each of the two encryption algorithms. Although, visual inspection is a way for detection the quality of encrypted images but it is not enough on judging. Therefore, other measuring factors are considered based on: measuring the maximum deviation between the original and the encrypted images, measuring the correlation coefficient between the encrypted and the original images, the difference between the pixel values of the original image and its corresponding pixel value of the encrypted one, the encryption time and the throughput. These measuring factors are applied on the two encryption algorithms to evaluate transmitted or local images containing many high frequency components and others containing very large areas of multiple colors as an example of binary images. The Cipher Block Chaining (CBC) and the Counter (CTR) modes are implemented and the results are compared.