The DNA cryptography is a new and very promising direction in cryptographic research. It is in the primitive
stage. DNA cryptography is shown to be very effective. Currently, several DNA computing algorithms are
proposed for many cryptography, cryptanalysis and steganography problems, and they are very powerful in
these areas. This paper discusses a significant modification of the old approach of using DNA and Amino Acids
based approach with Playfair Cipher to using the same approach with different encryption algorithm, i.e;
foursquare cipher to the core of the ciphering process. In this study, a binary form of data, such as plaintext
messages, or images are transformed into sequences of DNA nucleotides. Subsequently, these nucleotides pass
through a Foursquare encryption process based on amino-acids structure.