Secured Image Encryption and Decryption Using Blowfish Algorithm

Abstract

By and large, we send numerous photos of ourselves and some other important ones to our acquaintances,close connections and so on.These pictures might hold private data and messages of a person, and thereexist a necessity to keep such data safe.Hence, in order to secure such data,image encryption and decryption process by using blowfish algorithm has come into existence.With the advancement in the exchange,sharing of data by computerized systems, there is an urge to protect the data from unauthorized persons.With the evolution of interactive media applications, the safekeeping of information turns into a prominent matter for the interchanging of photos.Thefocus of this paper isto encrypt and decrypt an image with the help of a private(secret) key block cipher which is of sixtyfour(64) bits. Blowfish approach is designed to improve the safety of the images but also to enhance the efficiency . This algorithm uses a variable key of size up to 448 bits. The blowfish algorithm is opposed to illegal attacks and works much more faster and efficient than the other algorithms. Here, the data bit stream of the primary image is split into the limit of the block of the Blowfish algorithm.Then with the help of a key and encryption algorithm, the initial image is encrypted which is not visible to anyone. Later the encrypted image is decrypted with the help of the same key used in encryption process and a decryption algorithm. The decrypted image is nothing but the original image. The images encrypted and decrypted by blowfish can be of any saved size in tagged image file format(TIF),bit map(bmp),portable network graphics(PNG) and joint photographic experts group(JPG) etc. The primary advantage of this algorithm is that it can encode and decode both black and white and colour images.