A Raspberry Pi Zero at the heart of space station security

While it costs only a few Dollars, the Raspberry Pi Zero is at the heart of the European Special Agency’s cybersecurity strategy. Enclosed in a small cube, it has made it possible to test encryption methods robust enough to bypass ionizing radiation disturbances.While it costs only a few euros, Raspberry Pi Zero is at the heart of the European Special Agency’s cybersecurity strategy. Enclosed in a small cube, it allowed to test encryption methods robust enough to bypass the interference of ionizing radiation.

At the beginning of this month, the Air and Space Force organized its first space warfare exercise. Named AsterX, a nod to the first French satellite, Asterix launched in 1965, it made it possible to simulate cyberattacks on French satellites. A great novelty, whereas the cybersecurity of space systems was until recently an unthinkable concept, since nobody imagined that we could take control of a satellite. In the spirit of strengthening the cybersecurity of space stations, the European Space Agency (ESA) announces that it has just conducted a 22-month experiment on the International Space Station (ISS). The star of this mission is a simple Raspberry Pi Zero costing only a few euros. An operation that ESA considers to be one of the lowest cost ever carried out in orbit. Dubbed Cryptography ICE Cube (CryptIC), the mini-computer was used to encrypt the links.

Ensuring this encrypted link between space and Earth is much more complicated than only on our Planet. This is what Emmanuel Lesser, an engineer at ESA, points out, explaining that ‘space is riddled with charged particles that can randomly invert bits which disrupt the bond’. In the end, with these disturbances, the encryption keys on Earth and in space no longer correspond.

There are already operational encryption systems that exploit “hardened” components in the face of ionizing radiation. These are called rad-hard components. They are expensive and they can cost the price of a small CubeSat satellite alone. In addition, the production time is also important. In other words, it is not a solution for small missions. The ESA engineers therefore worked on a reliable and inexpensive system. The CryptIC system was developed internally by ESA’s Software Product Assurance section using a basic Raspberry Pi Zero. The scientists then evaluated two encryption approaches. The first process was to restore the key in case of corruption to minimize communication interruptions. The second was based on redundant copies of the encryption key. These copies were stored in programmable logic circuits (FPGA). In the event of a problem, another copy would replace the defective part while it was being reconditioned.

The cube enclosing the Raspberry Pi Zero measures 10 centimeters. In addition to two encrypted transmission methods, it tested commercially available computer memory. He was also carrying a radiation dosimeter.

A reliable and economical system

Overall, ESA engineers are satisfied with their system. “We’ve had radiation events almost every orbit, but we’ve only had disruptive encryption events every three months or so,” Lesser said. The CryptIC system also included other experiments, including the evaluation of the performance of commercial computer memories in the space environment. Finally, CryptIC also contained a radiation dosimeter supplied by CERN to raise the level of radiation on Earth and in particular on the area of the «South Atlantic Magnetic Anomaly».

Concretely, the Raspberry Pi Zero has been covered with a plastic coating and the whole fits in a cube of 10 centimeters. This cube concept is also frequently used on the ISS. The Ice Cube, for International Commercial Experiments, makes it possible to conduct technological experiments in microgravity. Similarly, this is not the first time that a Raspberry Pi has integrated the ISS. Every year, ESA and the Raspberry Pi Foundation organise educational challenges so that children can operate their code on the space station.

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