Abstract: We are living in a world where there is a danger every fraction of second. With the world becoming a global village, we live in an e-society where everyone is vulnerable to numerous possible cyber attacks. But there is also a way to pay hide to such unforeseen situations. Cryptography is one field which was developed with a sole aim to secure every entity. There are various types of techniques and algorithms available. This paper is aimed at explaining DES in an innovative way. DES algorithm or symmetric block cipher consists of 16rounds. There are various other algorithms which are based on DESís Fiestel structure. Hence, there is always a need to explain the actual working of DES. Therefore, through his papers the authors have tried to solve round 1 of DES, thereby explaining in detail how the round 1 key and cipher text is obtained with the help of an example and various tables. This paper will help not only in understanding the DES algorithm, but also the various other following algorithms. Also the cyber attacks and their corresponding counter measures can be understood more clearly if the working of DES is clear.

Keywords: Cryptography, Fiestel structure, Block cipher, permutation, substitution, left circular shift.