Journal: bioRxiv

Article Title: DNA-GUARD: molecular access control as a physical security layer for DNA data storage

doi: 10.64898/2026.08.12.744375

Figure Lengend Snippet: a . Cartoon of DNA-based data storage with added access control. A digital file is encoded onto nucleotide sequences represented by their nucleotide sequence. The encoded nucleotide sequence is synthesised as oligonucleotide molecules, yielding the molecularly encoded file. To reverse these steps, the oligonucleotides are sequenced, and the nucleotide sequence is decoded into the original digital file. A locking and unlocking layer is added to the DNA-encoded file by selectively preventing a subset of the oligonucleotides from being accessed. In the locked state, the sequencing of the accessible oligonucleotides yields an incomplete nucleotide sequence, preventing the digital file from being decoded. b . Comparison of encoding and retrieval of DNA-encoded digital data with and without access control. Top: Detailed schematic of encoding digital data information into DNA and subsequent retrieval and decoding. A digital file is algorithmically encoded into a set of chemically synthesized DNA strands, yielding a DNA file. To retrieve the encoded file, the strands are amplified using the polymerase chain reaction (PCR) to yield an amplified file. The amplified file is then read using next-generation sequencing (NGS), which allows the digital file to be decoded from the nucleotide sequences. Bottom: Detailed schematic of molecular access control of DNA-encoded data using DNA-GUARD. A digital file is encoded into DNA analogous to that described above. However, a subset of strands that encode the file are in a locked state. Locked sequences cannot be amplified during PCR, resulting in an incomplete file. After reading the nucleotide sequences using NGS, decoding is impossible, resulting in an unusable digital file. c . Reaction diagram of DNA file locking mechanism. The lockable strands within the DNA file contain a common region (shown in purple) complementary to the locker strands. During the annealing phase of a PCR cycle, the locker strand outcompetes the forward primer for hybridization with the lockable strands due to their increased length. Locker strands are modified such that they cannot be extended by the DNA polymerase, preventing the amplification of locked strands.

Article Snippet: All other DNA oligonucleotide pools were purchased at Twist Bioscience.

Techniques: Control, Sequencing, Comparison, Synthesized, Amplification, Polymerase Chain Reaction, Next-Generation Sequencing, Hybridization, Modification