The emerging science of DNA cryptography

Molecular biologists have long thought of DNA as an information storage device. The body processes this information with an impressive array of computing machinery which, since the 1990s, we’ve exploited to carry out a few of our own calculations.

DNA computing may not be fast but it is massively parallel. With the right kind of setup, it has the potential to solve huge mathematical problems. It’s hardly surprising then, that DNA computing represents a serious threat to various powerful encryption schemes such as the Data Encryption Standard (DES).

But if DNA can be used to break codes then it can also be exploited to encrypt data. Various groups have suggested using the sequence of nucleotides in DNA (A for 00, C for 01, G for 10, T for 11) for just this purpose. One idea is to not even bother encrypting the information but simply burying it in the DNA so it is well hidden, a technique called DNA steganography.

But that all sounds to simple for Nang King, an independent researcher who today puts forward an entirely new approach based on the way in which information from DNA is processed inside cells. The processing works in two stages called transcription and translation.

In transcription, a DNA segment that constitutes a gene is converted into messenger RNA (mRNA) which floats out of the nucleus and into the body of the cell. this happens only after the noncoding parts of the gene have been removed and the remaining sequences spliced back together.

In translation, molecular computers called ribosomes read the information that mRNA carries and uses it to assemble amino acids into protein chains.

This is a one way process. Information can be transferred from DNA to a protein but it cannot be converted back. There reasons are various. How would this process know where to reinsert the noncoding regions of DNA that were originally cut out or what these noncoding sequences would have consisted of in the first place?

Nang’s idea is that Alice encodes her message in the original DNA sequence and allows this to be transcribed and translated. The resulting protein is then like a public key which can be sent to Bob through a public channel. Meanwhile, Alice sends Bob the secret key which consists of the information he needs to reassemble the DNA such as the location of the noncoding regions that need to be reinserted.

Nang says that this form of cryptography is surprisingly secure to a number of powerful attacks. But he also points out various weaknesses such as that the encryption becomes increasingly difficult if more complex keys are used.

But it piques the interest for sure. And as an additional weapon in the cryptographer’s armoury, it’s surely an idea worthy of further study.

Ref: arxiv.org/abs/0903.2693: A Pseudo DNA Cryptography Method