University of Dhaka
This paper provides a security method which can be used for data that contains alphabets, numerals and some special symbols during their transmission. A discussion about cryptology and the existing polybius cipher is made. The existing polybius cipher is based on the use of a 5X5 matrix of letters constructed using numbers from 1 to 5. This square can allow the text that contains alphabets only. For this reason, the authors have proposed an improvement to the existing polybius cipher, in which an 8X8 matrix can be constructed.