Image Encryption and Decryption from Pixel Values using VHDL

摘要

Computers have already established its responsibility and performance in all fields like Banking, Hospitals, Military, Education, Space and Scientific applications etc. The most important thing to be considered is that, in all these above mentioned applications and issues, data's and images are completely stored in computers and a reduced amount of data's as papers in files. These data's and images stored in computers, when needed, are to be transmitted over short and long distance through computer networks for various applications. These data's and image include personnel details of customers in banking, details of patients, staffs and doctors and images related with patient's treatment in hospitals, confidential data's of country, enemy or target and their positions in military, details of students, teachers and their family in educational institutions, details of research and scientific experiments which include new inventions and findings, etc. During the time of transmission, there may occur a chance for these highly confidential data's to fall into wrong hands. As a result, it may lead to false treatment, declination of war, wrong dealings in banking, misuse of students and teachers details from educational institutions, etc. Hence, it is an unavoidable fact that the data transmission must be highly and completely secured. Thus, there arises the need of cryptography and its techniques. Cryptography is the art of achieving security by encoding messages to make them non-readable. So, to ensure security, the images must be encrypted before it is transmitted over the computer networks. Encryption can be defined as a process of disguising a message so as to hide the information it contains. Decryption is the reverse process of Encryption. Here, in my project, images are encrypted and decrypted using Blowfish algorithm which can use a key of variable size up to 448bits and it employs feistel network which iterates a simple function 16 times. The image processing part which includes the visualization of the image before and after encryption and decryption is done using Matlab software and the image encryption-decryption part is done using VHDL (Very high speed integrated circuits Hardware Description Language).