The purpose of this algorithm is to offer heightened security for data transmission. The data may include any alphabet, numerals, or special characters. This work proposes an improved version of a 3-D Playfair cipher, by improving the complexity of encryption and decryption. The algorithm uses a 5x5 key matrix for encoding, which not only increases the complexity by providing each character with threedimensional uniqueness, but also eliminates the idea of dummy characters required in other versions of this cipher. One can consider various types of cryptography attacks and comparisons of the resistance offered by the proposed algorithm with the resistance offered by existing algorithms to judge its practicality.