Proposal for encryption by using modified play fair algorithm and bioinformatics techniques

Playfair cipher is a classic encryption technique that is hard to be manipulated manually but apart from the advantages found in playfair cipher there are also many weakness, can be solved by using modern cryptographic algorithms. This work is about securing text by using modified Play fair algorithm. The encryption and decryption processes are done by using secret key and message provided by the user. The encryption and decryption process depended on using same key. The proposed modified Play fair algorithm depended on using biomolecular computing. The strength of this work represented by encrypting any type of characters or numbers and symbols by using the proposed method comparative to the previous works which is used to encrypt only English characters with some numbers. The strength of this work represented by encrypting any type of characters or numbers and symbols by using the proposed method comparative to the previous works which is used to encrypt only English characters with some numbers. The proposed technique depended on using modern cryptographic methods like bioinformatics technique. The generated key depended on using secure lock up table which is generated from another secure lock up table. Also the insertion process between duplicated character is removed, so this is saved the time and storage space. The size of the proposed modified Play fair matrix includes 4 columns and 16 rows instead of 5*5 matrix of conventional method. In this work the matrix of equal dimensions was not required; the amino acid codes(mRNA codes) are used in this work. The amino acid codes are also converted to special symbols; this means instead of using triple replacement of amino acid codes the triple characters are converted to one symbol. A single replacement was used, by this the size of encrypted text was decreased to 1:3 of using triple replacement. Each three character of amino acid codes is become represented by one character and this is also leading to save memory storage 3 times of using original representation of amino acid codes. The experimental results showed that the proposed method achieves good results; it was passed a proximity 13 tests of 14 NIST tests. The other 2 NIST tests are not worked from the original software of 16 NIST tests so 14 NIST tests are used in this paper. the proposed method overcomes the limitation of the previous methods in terms of encrypting any data types in Arabic, English, Latin language, numbers and symbols. Also the experiments show that the proposed method consumed few milliseconds in the encryption and decryption process and there is 75% changes in the cipher texts when using keys different in only one bit.