Advancing DNA Steganography with Incorporation of Randomness.

DNA has become a promising candidate as future data storage medium, which makes DNA steganography indispensable in DNA data security. PCR primers are conventional secret keys in DNA steganography. Brutal force testing of different primers will be extremely time consuming, and practically unaffordable when high throughput sequencing is used. However, the information can be sequenced and read once the primers are intercepted. New steganography approach is needed to make the DNA-encoded information safer. Herein, by mixing information DNA with partially degenerated DNA library containing single or multiple restriction sites, we build an additional protective layer, which can be removed by desired restriction enzymes as secondary secret keys. As PCR is inevitable for reading DNA-encrypted information, heating will cause reshuffling and generate endonuclease-resistant mismatched duplexes, especially for DNA with high sequence diversity. Consequently, with the incorporation of randomness, the DNA steganography possesses both quantum key distribution (QKD)-like function for detecting PCR by an interceptor and self-destructive property. It is noteworthy that the background noise generated through the protective layer is independent from any sequencing technology including Sanger and high throughput sequencing. With a DNA-ink incorporating the steganography, we have shown that the authenticity of a writing can be confirmed only by authorized person with the knowledge of all keys.