The team photographed a random two-dimensional array of T cells in solution. digitised the image by creating pixels on it and marked the pixels as "ones" and the empty spaces as "zeros", the website Phys.org reported.

The researchers — assistant professor of engineering science and mechanics Saptarshi Das, graduate student in engineering science and mechanics Akhil Dodda, graduate student in electrical engineering Akshay Wali and postdoctoral fellow in engineering science and mechanic Yang Wu — said this approach to creating encryption keys could not be cloned or reverse engineered.

Said Das: "Currently, encryption is done with mathematical algorithms that are called one-way functions. These are easy to create in one direction, but very difficult to do in the opposite direction.

"However, now that computers are becoming more powerful and quantum computing is on the horizon, using encryption that relies on its effectiveness because it is monumentally time-consuming to decrypt won't fly anymore."

The team used living cells because they can be kept around for a long time and, as they move around, can be photographed repeatedly to create new encryption keys.

They are using 2000 T cells per key at the moment and said in a recent paper that even if someone knew the mechanism for key generation — including cell type, cell density, key generation rate and key sampling instance — it was not possible to breach the system using that information.

Said Wali: "We need something secure, and biological species-encrypted security systems will keep our data safe and secure everywhere and any time."