Message encryption techniques are now the most important safeguards for our data and communications. The use of networks and the internet has sped up the development of message encryption technology. If sensitive, private messages are shared over unsecured networks, there is a possibility of an attack, theft, or hacking of the communications. It has been revealed that using cryptographic techniques is essential for shortening this period. The Caesar Cipher, Hill Cipher, and others are a few examples of the symmetric enciphering methods. The enciphering method given in this article encrypts and decrypts the input messages to generate a complex cipher using a self-invertible key matrix and an adjacency matrix of the pan graphs. Since the key matrix we are using is the self-invertible matrix, whose inverse always exists, we can decode the cipher without having to compute the inverse of the key matrix. The reduction in computational complexity facilitates our capacity to determine the inverse of a key matrix.