Supervisor: Matthieu LABOUSSE
Co-supervisoir: Yannick RONDELEZ

matthieu.labousse@espci.fr , yannick.rondelez@espci.fr
Laboratory: Gulliver, CNRS, ESPCI Paris PSL Université

Start date: Fall 2026 to be defined with the applicant.

Essentially, all of our online data are stored on hard drives in binary form (1 and 0). The information is partitioned, duplicated and spatially relocated to ensure availability and security. Soon, the total footprint of the infrastructure that allows us to manage and store these data will exceed the surface area of a middle-size country, with unsustainable energy consumption. Moreover, the lifetime of standard storage equipment is of the order of a few decades if left unreplaced. This model of growth will soon reach its limits, for economic, geostrategic and societal acceptance reasons. DNA is also another form of information storage medium. A DNA strand can be seen as a quaternary information sequence (A, T, C, G). It has recently become possible to write, read any DNA sequence and the lifetime of this information repository exceeds that of any hard drive by at least three orders of magnitude. Moreover, it would take a volume of DNA the size of a car to store all the data of mankind. The speed of reading and writing data in the form of DNA could quickly reach performance and economic efficiency comparable to that of a hard disk thanks to an intrinsic parallelism that is beyond compare. There remain significant fundamental and applied scientific challenges to achieve such a goal by the end of the decade.
In that context, it is crucial to be able to store information securely, in particular by regularly re-encrypting this massive amount of molecular data. The most reasonable strategy is to perform these operations in vitro directly and without using any form of digital intermediary. The aim of this PhD thesis is to perform the first experimental proof of concept of advanced in vitro DNA ciphering based on the fundamental principles of symmetric cryptography. On one hand, and in contrast with in silico data processing, a very limited set of operation is permitted by molecular biology and enzymes. On the other hand, the natural parallelization of the computational schemes with DNA surpasses any in silico computational capacities.
This PhD project is at the frontier between information theory and molecular biology. It will take place in the Gulliver laboratory, within a collaboration between Matthieu LABOUSSE who is theorist in out-of-equilibrium physics and Yannick RONDELEZ, an experimentalist in molecular programming. The candidate should have solid experimental skills in molecular biochemistry and strong curiosity for cryptography and information theory. Gulliver is a dynamic and multidisciplinary laboratory at the ESPCI, in the center of Paris. Its research fields range from theoretical physical chemistry, soft matter, molecular programming, statistical physics to microfluidics. It offers an international and intellectually stimulating environment at the crossroads of many research fields.
École doctorale : Physique en Ile de France Direction : Matthieu LABOUSSE Financement : ANR Financement d'Agences de financement de la recherche