In this Help Net Security interview, Colonel Ludovic Monnerat, Commander Space Command, Swiss Armed Forces, discusses how securing space assets is advancing in response to emerging quantum threats. He explains why satellite systems must move beyond traditional cryptography to remain protected.
Monnerat also describes how future communication architectures will need to integrate quantum-safe methods without disrupting operations.
1LT Simon Reding also contributed to these responses. The responses are personal opinions of the respondents and do not necessarily reflect the views of the Swiss Armed Forces.
Satellite operators have long relied on traditional cryptography for command and control. Which aspects of these systems are most vulnerable in a post-quantum world?
The current standards typically rely on AES or similar symmetric encryption. While these symmetric algorithms are widely regarded as being secure even against attacks from quantum computers, they heavily limit the potential use cases and therefore how efficiently a satellite can be used securely.
As the satellite and the ground operators need to share the same key, parties involved in the production, launch and usage of a satellite must have absolute trust in each other. Asymmetric cryptography is much more flexible in this regard, as an actor can provide their public key which is only able to encrypt data, but not decrypt it.
It enables scenarios where data captured by satellites can be provided without the operator ever knowing what the data contains, or even transmitting control of a satellite to another operator without a single bit of secret information being transmitted between the two operators. It can also provide guarantees that the software on the satellite has not been tampered with. Precisely this flexibility is not provided without the use of a new set of algorithms in a post-quantum world.
Especially vulnerable are satellites that rely purely on RSA or ECC asymmetric encryption for authentication as they may be disabled or even hijacked by an adversary with sufficient quantum computing capabilities.
How do latency, bandwidth constraints, and orbital mechanics shape the design of quantum-safe encryption protocols for space-based systems?
Post-quantum encryption protocols running on traditional hardware largely implement the same set of constraints as in traditional asymmetric encryption. However, the messages exchanged to derive a common secret are multiple in size compared to the traditional algorithms, so bandwidth needs increase, and also higher memory and compute requirements for the hardware on board of the satellite are required to maintain the same performance.
What are the most significant integration challenges when applying quantum-safe encryption to existing satellite architectures, especially those already in orbit?
Satellites in orbit that use ECC or RSA for authentication, rely on the flexibilities gained by these protocols for their CONOPS, and don’t have sufficient compute on-board to migrate to a set of post-quantum algorithms, will face the biggest challenge. This leads to a necessary vertical compatibility between different generations of satellites, succeeding quite fast to each other, in order to reduce obsolescence when deployed in orbit.
Do you expect quantum-resilient standards to emerge first from the defense sector or through commercial satellite operators?
We can expect the industry to largely standardize the existing NIST Post-Quantum Cryptography standards, as they have with AES, RSA and ECC in the past. Commercial satellite operators able to adopt these standards early may be able to propose a very unique value proposition to defense clients, offering their services loosely following zero trust principles.
Especially for smaller countries on a lower budget, the ability to securely “borrow” satellites or payloads already in orbit to acquire sensitive information over a given period of time is interesting, and benefits sustainable space operations as a whole as less satellites have to be launched.
If we project ten years ahead, what does a quantum-resilient space communication architecture look like, and what are the biggest unknowns that could derail it?
The majority of the satellites will likely use a combination of traditional asymmetric algorithms for performance reasons, with the option to switch to post-quantum algorithms should there be evidence that quantum computing has reached the performances required to break the traditional encryption. Of course, there will be many use cases, especially in SATCOM, where the concept of “Harvest now, decrypt later” will dictate the use of algorithms that are regarded as safe from a quantum attack.
A worst case scenario is the accelerated development of quantum computing combined with discovered vulnerabilities in post-quantum algorithms, which, while very well studied by academia and institutions, have only been standardized in the last years and are yet to be widely adopted even in terrestrial information systems.