Extended 10 x 10 PlayFair Cipher

In this paper, the original 5×5 matrix of PlayFair cipher has been extended to 10 × 10 PlayFair table, in order to maximize all possible characters that might be accepted using an ordinary QWERTY keyboard layout. The goal of this enhancement is to provide basic modification of classical encryption technique that promotes a simpler algorithm that will not require a complex design of the program. The research includes the simulation of encryption based from the plaintext that will conclude to better suggestion of encryption keyword. The original rule of the cipher is also modified such as the characters used for the uneven plaintext and filler character to be used if in case the pairing before the encryption may have the same characters. The repetition of characters on the keyword is allowed, hence the succeeding repeated characters will be neglected. As part of the experiment of this extended cipher, avalanche effect is tested to validate the extreme changes on the ciphertext.