  In many research works, there has been an orientation to studying and
developing many of the applications of public-key cryptography to secure the
data while transmitting in the systems, In this paper we present an approach to
encrypt and decrypt the message text according to the ASCII(American Standard
Code for Information Interchange) and RSA algorithm by converting the message
text into binary representation and dividing this representation to bytes(8s of
0s and 1s) and applying a bijective function between the group of those bytes
and the group of characters of ASCII and then using this mechanism to be
compatible with using RSA algorithm, finally, Java application was built to
apply this approach directly.
