Cryptography means concealed writing and the essence of a cryptographic application is to ensure that two parties can communicate privately over a channel in which a third party cannot detect what is being communicated. Currently, information security is the paramount challenge in our life on a daily basis. In this paper, we proposed a secret password that helps to protect data and massage in a secure way. We developed a secret password by using cryptography and M modulo N graceful labeling on a complete bipartite graph with a secure key known only by the system manager. Further, our proposed secret password improves the security of the message which traverses over the insecure system. This also involves private keys Security is ensured because only the person with the relevant private key can decode the message. Also we illustrated these mathematically.

Cryptography, Graceful labeling, M modulo N graceful labeling, complete bipartite graph, secret password.