University of Technology-IraqEngineering and Technology Journal1681-690034220160201Image Encryption Using Block Cipher Based Serpent Algorithm27828611265910.30684/etj.34.2B.10ENYossra Hussain AliHaider Aabdali RessanJournal Article20160101In an encryption scheme, the message or information, referred to as plaintext, is encrypted using an encryption algorithm, generating cipher textthat can only be read if decrypted.A proposal algorithm forimages protectionis depending on the block cipher serpent algorithm infeistel network structure, because numbers of round and linear transformation function and used block size of 512 bits rather than 128 bitshas more complexity for attacker or unauthorized person to discover original images.In modified serpent, the correlation coefficient decreases to below the traditional serpent algorithm. When 64*64 pixel bitmap image is used the correlation coefficient for gray level between plain image and cipher image is (0.0023) in modified serpent and (0.0814) in traditional serpent.https://etj.uotechnology.edu.iq/article_112659_f70ecaf7af6cec07074e44a0dbcaa4bc.pdf