One of the most concerned issues during data transmission is the security of information exchange. Cryptographic schemes are needed to protect the vital information from intruders or against illegal access and modifications. The 3D Playfair Cipher Algorithm is a symmetric encryption scheme that uses substitution technique. It originates due to the constraint of the classical 5x5 Playfair Cipher. The intended improvement emphasizes on proposing a more secure secret key generation and enhancing the encryption scheme of the 3D (4x4x4) Playfair cipher. The proposed study utilizes a 4x8x8 key matrix that holds 256 ASCII characters and implements a dual Cipher Block Chaining (CBC) method. Experimental results show a notable improvement in the security performance of the proposed study, wherein it achieved a strict avalanche criterion (SAC) of 54.17%. The proposed enhancement has a notable Avalanche Effect increase of 52.78% between the proposed improvement and the original 3D Playfair, indicating that the proposed algorithm is better compared to the original one. Furthermore, the proposed improvement also passed the randomness test.