Image Encryption and decryption using CAST-128 with proposed adaptive key

Abstract

Encryption of an Image is an interesting region in the security of an information field. Encrypting of an image is various from text because of its features. It is difficult for dealing with encryption of an image by employing conventional methods of encryption. The suggested methodology had been employed CAST-128 algorithm with proposed adaptive key for encrypting images. CAST-128 is a procedure that is designing for symmetric algorithm for encryption which has Feistel classical network containing 16 rounds and can operate on 64-bits blocks of plain text to introduce 64-bit blocks of cipher-text. A key's size varies from 40 bits to 128 bits in 8-bit increments. The proposed adaptive 128-bits key can be extracted from the main diagonal of the original image before encryption and apply MD5 hash function to increase the key security. The experimental results explained that the time consuming for both encryption and decryption when using proposed adaptive key is less than static key.