Are there any weaknesses in quantum encryption?

"Quantum key distribution relies on fragile quantum signals, and even small misalignments between transmitter and receiver can significantly affect its performance. A recent study introduces a new analytical framework that reveals how different types of pointing error influence error rates and secure key generation. Credit: Shutterstock"  (ScitechDaily, Scientists Uncover Hidden Weakness in Quantum Encryption)

There are mistakes in every system that humans created. The quantum encryption process always starts  in binary computers. So the attacker can benefit from connections that interconnect quantum and binary states. The binary computer encodes data and transfers it to the quantum level, where it is stored in qubits. The information. That which is connected with qubits is connected in a physical particle. There is always a possibility that if there is space between the quantum channel and the qubit, somebody can benefit from that space. 

That allows attackers to put a particle between the qubit and the quantum channel. In the so-called “tangent attack”. That is the quantum version of the “Man in the Middle” attack; the attacker uses the information. The quantum system is used for adjusting qubits for superposition and entanglement. The attacker brings their own quantum system near the information channel. Then the attacker puts information. Travel through the attacking system. 

That makes it possible to transport information from the qubit to that particle. This thing should remove information from the qubit. But the programming determines. How does that system handle? This kind of situation? Typing errors, or errors in pointing, can cause a situation where the qubit is destroyed. In that case, the system must generate a new qubit. And make the information resending process. 

“Quantum key distribution (QKD) is a next-generation method for protecting digital communications by drawing on the fundamental behavior of quantum particles. Instead of relying on mathematical complexity alone, QKD allows two users to establish a shared secret key in a way that is inherently resistant to interception, even if the communication channel itself is not private.” (ScitechDaily, Scientists Uncover Hidden Weakness in Quantum Encryption)

How effective is this system? That depends on the precise control of the information channels. If those information channels are not tight, the attacker can steal information from the qubits by putting particles between the qubit and the information channel’s shell. If the quantum channel is not tight enough, aiming information through with precise accuracy is not possible. 

“By combining statistical models of beam misalignment with quantum photon detection theory, researchers derived analytical expressions for key performance indicators of QKD systems, clarifying the exact role of pointing error in degrading secure key generation.” (ScitechDaily, Scientists Uncover Hidden Weakness in Quantum Encryption)

"The study’s findings explain the effects of pointing error on quantum key distribution performance metrics, offering insights for improving real-world systems. Credit: “Quantum bits” by Argonne National Laboratory" (ScitechDaily, Scientists Uncover Hidden Weakness in Quantum Encryption)

“The researchers focused on widely used BB84 QKD protocol and modelled pointing errors using Rayleigh and Hoyt distributions, which model horizontal and vertical beams better than simplified models used in earlier work. This leads to more accurate characterization of random pointing errors.”  (ScitechDaily,S cientists Uncover Hidden Weakness in Quantum Encryption)

That Reyleigh-Hoyt framework combination shows. The quantum information channel expansion. At a certain point. The Rayleigh distribution is connected to the Hoyt distribution. Or sector model. The Rayleigh distribution introduces a point of the information channel. And sector- or Hoyt distribution introduces the expansion of the information channel. 

“Using these statistical models, the researchers first derived analytical expressions for error and sift probabilities under pointing error, a first in the field. These were then used to compute the quantum bit error rate (QBER), which indicates the percentage of bits corrupted due to either system noise, environmental effects, and imperfections or attempted eavesdropping. QBER is therefore, a key performance metric. The researchers further used QBER to calculate the secret key rate (SKR) that measures the rate at which shared, secure keys can be generated. They analyzed the effects of pointing error caused due to both symmetric and asymmetric beam alignments.”(ScitechDaily,Scientists Uncover Hidden Weakness in Quantum Encryption)

“The results showed that an increased beam waist, and hence, increased pointing error, significantly degrades QKD performance, indicated by higher QBER and decreased SKR. Increasing receiver aperture size can improve performance, but only up to a certain level. Interestingly, asymmetric beam misalignment, where horizontal and vertical deviations are different, was found to be favorable for improving performance. The researchers also found that for achieving non-zero SKR, important for secure communication, increasing average photon numbers is required.”(ScitechDaily,Scientists Uncover Hidden Weakness in Quantum Encryption)

If somebody can affect the information channel. There is a possibility that the system resends the qubit to the attacker. Another possibility is that the attacker uses qubit synchronization information, which the system requires for superposition and quantum entanglement. In that case, those attackers can create their own qubits that they can use to steal information from the quantum system. This means that the attacker aims for a quantum entanglement through. The third-party system. We could call this thing the tangent attack. This requires that the attacker has their own quantum system, which can decode information from the quantum entanglement and then resend that information to the receiver. As I wrote before. 

https://phys.org/news/2026-01-errors-impact-quantum-key.html

https://scitechdaily.com/scientists-uncover-hidden-weakness-in-quantum-encryption/

https://en.wikipedia.org/wiki/Quantum_key_distribution

https://en.wikipedia.org/wiki/Sector_model

https://en.wikipedia.org/wiki/Rayleigh_distribution