DNA-Based LSB Steganography

1. Introduction

Various approaches and techniques have been proposed to preserve the confidentiality, integrity and availability of sensitive data. Techniques based on cryptography and steganography are the most extensively investigated and developed.in cryptography, information is converted into some scrambled messages, using mathematical and logic concepts, and then transmitted over an untrustworthy media. The encryption process takes plaintext (message to send) as input and generates ciphertext(encrypted message) as output by using a secret key and encryption algorithm. In order to recovering an encrypted message back to its original format, the receiver apply a decryption algorithm on the ciphertext using decryption key as shown in figure 1.

Figure 1.

Encryption/decryption model

Encryption and decryption are carried out according two mechanisms. The first one called symmetric cryptography uses a common key for both encryption and decryption. This key could be privately shared by the sender and the receiver. However, the second mechanism, asymmetric cryptography, requires each user to have two keys: a public key and a private or secret key. The plain text is encrypted using the receiver’s public key and the cipher text is deciphered using a private key. Cryptography has been evolved through the use of new concepts and techniques such as deep learning, quantum and biometrics. More recently, dna-based cryptography has emerged as a promising new scientific field in information security. Actually, it is derived from the dna computing characterized by low energy efficiency, huge parallelism, and extraordinarily large information storage capacity (khobzaoui & al. 2022). It combines the classical solutions in cryptography with the chemical characteristics of biological dna sequences. The message is firstconverted to its binary format using conventional ascii table and then encoded as a dna sequence, which is the combination of the four nucleotide bases namely a (adenine), c(cytosine), g(guanine), t(thymine) according to table1. After that, a set of dna computing operations are applied to manipulate and exploit the obtained dna sequence.