hybrid encryption using playfair and rsa cryptosystems

The security is demanded to transport important data over the network. in this work a hybrid encryption depending on playfair cipher and rsa algorithm is proposed to give more confidentially and get rid of the defects of the two methods. the first cipher text is obtained by playfair cipher by using (812) expanded key matrix that is filled by decimal ascii characters of alphabets, numbers and common characters of ascii table while the final cipher text is obtained by rsa cryptosystem by applying it for blocks of two characters. the proposed hybrid encryption avoids to take large numbers in rsa algorithm and performs complex operations that need a long time to do. the proposed hybrid cipher is tight security that is difficult to analyze and detect from hackers and intruders.