Secure Image Encryption Using Block-based and Blowfish Symmetric Algorithms

Encryption is used to securely transmit data inopen networks. It can also be defined as the process ofobscuring information to make it unreasonable without specialknowledge. Encryption is the process of transformation theimages to ensure its security. Most of the available encryptionalgorithms are mainly used for textual data and may not besuitable for multimedia data such as images. This systempresents a block-based transformation algorithm based on thecombination of image transformation and a well knownencryption and decryption algorithm called Blowfish. Theoriginal image is divided into a random number of blocks andthen shuffle within the image. The generated image is encryptedusing the blowfish encryption algorithm. From the results, thecorrelation between image elements was significantly decreasedby using the proposed technique. It takes a variable-length key,from 32 bits to 448 bits. Blowfish is a fast cryptographicsoftware algorithm and symmetric and symmetric block cipher