International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 21 (2017) pp. 10828-10833 © Research India Publications. http://www.ripublication.com 10828 Secure Symmetric Encryption Scheme Using Genetic Algorithm Cimi Thomas M 1 Research Scholar, Department Of Computer Science, Karpagam Academy of Higher Education, Pollachi Main Road,Eachanari Post, Coimbatore, Tamilnadu, India. Orcid Id:0000-0002-8605-7440 Dr. S.Sheeja 2 Associate Professor and Head, Department of Computer Applications, Karpagam Academy of Higher Education, Pollachi Main Road,Eachanari Post, Coimbatore, Tamilnadu, India. Abstract Ensuring the security of sensitive and confidential data during transmission and storage is one of the greatest challenges faced by digital world. The most common technique used to protect data is encryption. Different encryption algorithms are available and they are used in security protocols to provide confidentiality, integrity and authentication. In spite of having strong encryption algorithms and security protocols, security breaches are still happening and reported frequently. Secure encryption schemes with new features different from traditional methods are needed to protect digital information. In this study a symmetric key encryption scheme based on DNA sequences is proposed. The proposed algorithm is a feistel cipher with many rounds and the round specific sub keys are generated by applying the principles of genetic algorithm. The study has proved that genetic algorithm is a viable method for selecting best fit keys for developing strong encryption schemes. Keywords: DNA cryptography, Encryption, Decryption, Genetic Algorithm, Feistel structure. INTRODUCTION The affordability of computing devices and easy access to World Wide Web has led to the development of wide range of web applications. These web applications require the transmission of personal and critical information over internet. There is tremendous increase in the number of online financial transactions owing to the popularity of E-commerce. Credit card information and user bank account details transmitted over network should be protected from unauthorized people. Ensuring the confidentiality and integrity of various databases is also challenging. DNA databases which has DNA profiles of people were initially used for criminal investigations. But now a days public genomic databases are available which are widely used to carry out research studies on genetic diseases and genetic genealogy. Security of these databases is a real concern as the DNA information can be misused in various ways. Encryption can be used to protect data during transmission and storage. Encryption algorithms can be classified as symmetric key encryption and asymmetric key encryption. Symmetric key encryption uses the same key for encryption and decryption. A number of symmetric key encryption algorithms are in existence and they are used in various security protocols and products. The advancement in computing and in the area of cryptanalysis demand the development or enhancement of existing encryption schemes. Researchers are trying to develop new cryptographic techniques which can withstand threats posed by quantum computers. In this study a symmetric key encryption scheme based on DNA sequences is proposed. The proposed algorithm has a feistel structure with multiple rounds of permutations and substitutions. The round specific sub keys for each round are generated by applying the principles of genetic algorithm. DNA cryptography is a new promising field which has attracted researchers in recent years. DNA (Deoxyribo Nucleic Acid) contains our unique genetic code and is made up of monomers called deoxyribo nucleotides. Each DNA molecule has two long strands of nucleotides and each nucleotide is made of deoxyribose sugar, phosphate group and a nitrogenous base. Nitrogenous bases are A (Adenine), G (guanine), C (Cytosine) and T (Thymine). A bonds with T and G bonds with C. These nucleotides appear in random order in each DNA molecule and the order of these nucleotides determine DNA’s genetic code. The strength of any cryptographic scheme is directly related to the randomness offered by them. Researchers have shown that randomness found in the nucleotide sequences can be efficiently used to create strong and reliable encryption schemes. The use of real DNA for developing crypto systems is not feasible currently due to sophisticated lab requirements. Genetic algorithm is an optimization method based on Darwin’s theory of natural selection. Genetic algorithm repeatedly modifies a population of individual solutions. The initial population is generated depending on the problem