Data Embedding Method Based on Steganography in Noncoding DNA Sequence

Abstract

DNA had been taking interest from researchers as the next generation data storage medium, based on the fact that DNA has a higher density than semiconductor and magnetic storage. All life-regulating information is contained inside the DNA, in form of nucleotide base sequences. Recent DNA technology made it possible to modify the arrangement of nucleotide bases, allowed us to insert external information to the DNA. This information requires adequate protection against attack or unauthorized reading. Therefore, a DNA steganography method is presented in this thesis, which had three main focus: security, capacity efficiency, and resist from mutations. The message (binary data) was encrypted using XOR cypher and then encoded by Reed-Solomon error correction code to make it resist from base substitution mutation. Next, message was segmented into short sectors and then embedded into noncoding DNA regions only to preserve the host DNA’s genetic information. Embedding algorithm transformed binary message into nucleotide base letters using randomized transform tables and modular arithmetic calculation. Each sector also had a parity base that worked as error detector and indel mutation handler. This method had two keys: encryption key and embedding key. Message extraction did not require the original host DNA but the two keys were compulsory. Experiments verified that proposed method gave higher bit-per-nucleotide (bpn) value in compare with previous works. Determined by the sector length, the capacity was ranged from 1 up to 2 bpn. Error correction code had successfully restored the original message for a given (10-4 × DNA length) bases of errors. Besides the encryption, randomized transform table created unique binary-base pairs for every noncoding regions, thus decreased the successful attack probability even lower.