Cipher Block Chaining Technique based on Euler Graph MPR Murthy 1 and CH. Suneetha 2 1 Sr. Assistant professor in Mathematics, GVP college for Degree and PG Courses(A), Visakhapatnam, India 2 Associate Professor in Mathematics, GITAM University, Visakhapatnam, India Author for Correspondence: schivuku@gitam.edu Abstract—The present Covid 19 pandemic has created a destruction towards the physical meet and physical talk among the people all over the world. All the communications like social, business, personal including secret are done by using digital techniques. Digitalization has become mandatory for all types of transmissions. Secure communication of secret information has become a hard task due to the extensive growth of wireless networks. It is essential for the service providers to add on extra security level for the messages in their transmission from one place to the other. The task of providing the security is done by encryption technique alone. Applied graph theory plays a crucial role in encryption technique as it has widespread special features equipped with easy and effective representation. The present paper explores a symmetric encryption technique using Eulerian circuits of weighted Euler graphs and simple logical operations. Index Terms— Euler Graph, Euler Circuit, Encryption, Decryption. I. INTRODUCTION A science of communication of secret information with protection in the presence of a harmful third party is cryptography. In the present era of extensive and thoughtless use of the internet as a basic means of communication creates a threat of hacking and stealing the secret information in the transmission medium. So, concealing the secret information illegible to unauthorized persons is most required aspect in communication network. Graph theory, a major part of applied mathematics has a wide role in the history of cryptography. Many complex problems in our day-to-day life can be represented and solved by graph structures as it provides simple and clear pictorial representation. The flexible properties of graph structures give an additional strength to cryptosystems. The history of cryptography shows diverse graph theory applications in the encryption process. The Relationship between graph theory and cryptography is very interesting. Graph Theory Euler’s Theory: A connected graph containing a Eulerian circuit is called the Euler graph [1]. Eulerian Circuit: A circuit which touches every edge of the graph exactly one and returns to the same vertex is known as Eulerian circuit. If all the vertices of the graph are of even degree, then the graph is called as Euler Graph. Euler Path: A graph meeting every edge of the graph and coming back to the same vertex is called the Euler Path. Grenze ID: 01.GIJET.8.1.8 © Grenze Scientific Society, 2022 Grenze International Journal of Engineering and Technology, Jan Issue