Classification of Ciphers

Certificate This is to certify that the work contained in the thesis entitled Classification of Ciphers, by Pooja Maheshwari, has been carried out under my supervision and that this work has not been submitted elsewhere for a degree. Abstract In cryptanalysis of an unknown cipher first step is to identify the cipher and then to break it. To identify the cipher we need to classify them. Classifying ciphers means identifying the cipher, which has resulted the given ciphertext encrypted by that unknown cipher. In this thesis, classification of classical ciphers was done with very good accuracy. For classification of modern ciphers like DES and IDEA, several schemes have been examined. Slightly positive results were obtained for modern ciphers classification. ii Acknowledgements I would like to express deep gratitude towards my thesis supervisor Dr. Manindra Agrawal, for his excellent guidance and help during my thesis work. He was always available to help, guide, and encourage me. He has always been very patient and understanding. I am also thankful to all the faculty members of Computer Science & Engineering Department for their encouragement, which has brought me to this competent stage. I extend my thanks to the technical staff of the department for their cooperation and help. listening to my thesis problems and making my stay memorable one at IIT-Kanpur without which I would not have cheerfully completed this task. Finally I would like to mention my beloved parents for their love and affection. It is their trust and expectations that drives me always.