Quantum Hacking, Spying and New Generation Intelligence Technologies

The development of quantum communication technologies raises an important issue, that of quantum cybersecurity, which has two dimensions:

• The defense against a cyberattack by a sufficiently advanced quantum computer that may be capable of breaking current encryption protocols;
• The development of a quantum internet with new quantum-based encryption protocols.

The first dimension has been an issue for a while now, in the 2013 article  "The Nature and Content of a New-Generation War" by Col. S.G. Chekinov and Let. Gen. S.A. Bogdanov, published in the scientific journal "Military Though" the authors state that: 

"(...) A quantum computer may turn into a tool of destruction and a 21st century bomb for cyber-attacks to succeed. It will easily crack all codes and gain free, and virtually instant, access to all networks supporting the operation and security of government and military control agencies (...)" (Chekinov and Bogdanov, 2013, pp.18,19).

The NSA and NIST have been involved in efforts to develop post-quantum cryptography and quantum-resistant algorithms with one notable project being the Post-Quantum Cryptography Standardization Project. In this context, the research on quantum cybersecurity is critical.

Quantum communication games are ways to provide simple examples of basic dynamics associated with quantum communications, allowing us to address some theoretical properties regarding quantum cybersecurity in the context of quantum communications.

We can use quantum simulators to implement these games. In this case, we will use IBM Quantum Experience resources.

The quantum communication game below is a simple example that explores a few properties of quantum communications linked to measurement and interference and allows one to illustrate basic quantum hacking.

Let us consider, then, the first version of the game. Where Alice wants to send Bob a one-bit information, which means that she wants to send Bob either a "0" or a "1", but she is afraid that Eve may be listening in, then, instead of sending the information as a classical bit she sends Bob a qubit in either the superposition |+>=(|0>+|1>)/sqrt(2), or |->=(|0>-|1>)/sqrt(2).

Now, Bob knows that Alice uses the following coding protocol:

• |0> ->|+>
• |1> -> |->

Then, to retrieve the bit that Alice is sending, Bob just has to apply a Hadamard transform to get the original bit. Therefore, if Alice wants to send a 1, we have the following circuit (the barrier is separating Alice's side of the circuit from Bob's):

On the other hand, if Alice wants to send a 0, then we have the following circuit (again, the barrier is separating Alice's side of the circuit from Bob's):

If the circuit was run on the theoretical device, then the result would be 1, for the first case, and 0 for the second, if we run it on a physical device, then, we have noise, which means that we need to run it multiple times to get the dominant result.  This is equivalent to Alice automatically and repeatedly sending qubits encrypted in accordance with the protocol, through a noisy channel, with Bob measuring it at the end.

The following bar charts provide the results from running each circuit 1024 times in the ibmq_london quantum device. We can see that in the first case, Bob gets the right message 90.625% of the times, and in the second case, Bob gets the right message 99.512% of the times.

Now, what if Eve is listening in but does not know Alice and Bob's communication protocol? Then, what Alice did was to encrypt the classical information into a superposition qubit. Which means that if Eve hacks into the channel, measuring Alice's qubit before Bob then Bob will know that the channel has been hacked, and Eve will only get a random distribution of 0 and 1, which means that, with this quantum encryption protocol, Alice and Bob are protected against this type of measurement hack.

As an example, let us consider that Alice wants to send a "1" to Bob (the "0" will just be the same but without the initial X gate), then she will encrypt it as in the protocol, therefore, we have the following quantum circuit (again, the barriers separate each player's moves in this game):

There are two classical registers in this game, Bob and Eve's, Eve will store the result from measuring the qubit sent by Alice, and then Bob will implement the decryption protocol but when he does so, Eve will already have performed a measurement, so that Bob and Eve will get a random distribution over the full computational basis, therefore, the initial message becomes noise. If we run the circuit on the ibmq_qasm_simulator, we get the following results for Bob and Eve.

In this case, Bob will get a "0" about 50% of the time and a "1" about 50% of the time, the same as Eve, with uncorrelated measurements between both players. Bob will automatically know that Eve has hacked the channel and Eve will not know what information Alice sent, the channel becomes in a sense corrupted by noise. In this way the quantum encryption can be stated to have an adaptive response to a quantum measurement hack, securing the channel against this hack.

Now, let us introduce intelligence operations on the part of Eve and assume that Eve has learned of Alice and Bob's protocol, the question is: can Eve hack the channel and fool both Alice and Bob?

She can, the hack is to decrypt Alice's message, measuring the result, re-encrypting Alice's message, using Alice's protocol, and sending the results to Bob. The following circuit shows the hack for the previous circuit:

If the circuit is run on the ibmq_qasm_simulator, we get the following result:

As expected, both Bob and Eve get the right result, Eve knows what Alice is sending and neither Bob nor Alice know that Eve has, effectively, hacked the channel!

Research into quantum encryption algorithms for secure quantum communications has protocols such as the BB84 and the Ekert protocols (Zygelman, 2018). The issue of how to hack quantum encryption protocols is a major point in quantum hacking research.

There are various ways to hack quantum communications, in this research area, cybersecurity, intelligence activities and quantum computation intersect. In quantum communications, eavesdropping is possible without interception, exploiting the features of quantum hardware, in this case, the dead time of single-photon detectors, this was introduced by Weier et al. (2011), the abstract to the article that we quote next shows the basic approach:

"The security of quantum key distribution (QKD) can easily be obscured if the eavesdropper can utilize technical imperfections in the actual implementation. Here, we describe and experimentally demonstrate a very simple but highly effective attack that does not need to intercept the quantum channel at all. Only by exploiting the dead time effect of single-photon detectors is the eavesdropper able to gain (asymptotically) full information about the generated keys without being detected by state-of-the-art QKD protocols. In our experiment, the eavesdropper inferred up to 98.8% of the key correctly, without increasing the bit error rate between Alice and Bob significantly. However, we find an even simpler and more effective countermeasure to inhibit this and similar attacks." (Weier et al., 2011).


Quantum intelligence technologies involves the development of research on the application of quantum technologies to intelligence activities, intersecting Quantum Science and Intelligence Studies. A specific area of research within quantum intelligence technologies is the research into quantum secure communications and how to use them to hack quantum communications systems. While this research is taking its first steps, research into algorithms and hardware issues is fundamental for the advancement of the field.

Of course, the ability of quantum computers to break classical encryption depends upon the development of quantum computation. In the Intelligence Advanced Research Projects Activity (IARPA), there have been some projects into quantum technologies, specifically directed at the advancement of quantum computation:

• Logical Qubits (LogiQ): aimed at overcoming the limitations of current multi-qubit systems by building a logical qubit from a number of imperfect physical qubits (https://www.iarpa.gov/index.php/research-programs/logiq).
• Quantum Enhanced Optimization (QEO): aimed at harnessing quantum effects required to enhance quantum annealing solutions to hard combinatorial optimization problems (https://www.iarpa.gov/index.php/research-programs/qeo).
• Multi-Qubit Coherent Operations (MQCO): aimed at solving the technical challenges involved in fabricating and operating multiple qubits in close proximity (https://www.iarpa.gov/index.php/research-programs/mqco).
• Coherent Superconducting Qubits (CSQ): aimed at demonstrating a reproducible, ten-fold increase in coherence times in superconducting qubits (https://www.iarpa.gov/index.php/research-programs/csq).
• Quantum Computer Science (QCS): aimed at exploring questions relating to the computational resources required to run quantum algorithms on realistic quantum computers (https://www.iarpa.gov/index.php/research-programs/qcs).

The majority of the projects above is related to the development of quantum computing technologies. However, in the wider range of quantum intelligence technologies, advancements such as quantum radar research can be expected to be developed in the near-future, especially around the building of a quantum internet, in which case, quantum cryptography and secure quantum communications become a fundamental research area.

Chekinov, S.G. and Bogdanov, S.A. (2013). The Nature and Content of a New-Generation War. Military Thought, 4, 12-23.

Weier, H.,  Krauss, H., Rau, M.,  Fürst, M.,  Nauerth, S. and  Weinfurter, H. (2011). Quantum eavesdropping without interception: an attack exploiting the dead time of single-photon detectors. New Journal of Physics, 13.

Zygelman, B. (2018). A First Introduction to Quantum Computing and Information. Springer.