Abstract: There are continuous threats to network technologies due to its rapidly-changing nature, which raises the demand for data-safe transmission. As a result, the need to come up with new techniques for securing data and accommodating the growing quantities of information is crucial. From nature to science, the idea that genes themselves are made of information stimulated the research in molecular deoxyribonucleic acid (DNA). DNA is capable of storing huge amounts of data, which leads to its promising effect in steganography. DNA steganography is the art of using DNA as an information carrier which achieves high data storage capacity as well as high security level. Currently, DNA steganography techniques utilize the properties of only one DNA strand, since the other strand is completely dependent on the first one. This paper presents a DNA-based steganography technique that hides data into both DNA strands with respect to the dependency between the two strands. In the proposed technique, a key of the same length of the reference DNA sequence is generated after using the second DNA strand. The sender sends both the encrypted DNA message and its reference DNA sequence together into a microdot. If the recipient receives this microdot uncontaminated, the sender can safely send the generated key afterwards. The proposed technique doubles the amount of data stored and guarantees a secure transmission process as well, for even if the attacker suspects the first-sent DNA sequence, they will never receive the key, and hence full data extraction is nearly impossible. The conducted experimental study confirms the effectiveness of the proposed.