Researchers at Linkoping University and Stockholm University in Sweden have found that the "energy-time tangling" method that has become the basis of many quantum cryptosystems is not unbreakable. This method itself has a vulnerability that is easy to attack. ", and quantum cryptography can also be cracked. "Because of this security vulnerability, the transmission process of quantum encryption may also be eavesdropped without being discovered. We discovered this in theoretical calculations, and then confirmed this through experiments with our colleagues in Stockholm," Lin Xueping University Jan-Ake Larsson, professor of information coding, said. Quantum cryptography is considered to be an absolutely safe method of information transfer and should be unbreakable in theory. Many research groups around the world are working to make quantum cryptography capable of withstanding a variety of different interferences, and so far it has been able to properly resolve the interference or attacks it detects. Quantum encryption technology is now commercially available, but there are still many doubts about whether it can be used in practice. "Most of them are just rumors. I haven't seen any systems using this technology. But I know that some universities have been testing the network to achieve secure and reliable data transfer," Larsson said. Researchers have studied the energy time entanglement technique used in quantum cryptography, mainly in connection with key generation. The technique delivers photons in different directions at exactly the same time. The two ends of the connection are interferometers. After adding a small phase shift, they will cause interference when the data is originally used to compare the similarities of the two ends. If the photon stream is monitored, it will generate noise, which can be revealed by the theorem of quantum technology (Bell inequality). On the other hand, if the connection is secure and there is no noise, the remaining data or photons can be used as a key to protect the information. Experimental setup of the Franson interferometer - including a light source, 2 & TImes; 2 coupler (C), delay loop (ΔT), phase modulators ΦA and Φ, and detector (D) (Source: Jonathan Jogenfors, Linkoping University) Lin Xueping University professor Jan-Ake Larsson and doctoral student Jonathan Jogenfors discovered that if a traditional light source is used instead of a photon, the eavesdropper can find the key-code string. Therefore, the eavesdropper can read the data smoothly without being detected. Even if the attack is in progress, the safety test based on Bell's inequality is completely unresponsive. The physicist at Stockholm University then actually conducted experiments and confirmed that the light source was completely replaced, thus causing the possibility of information being eavesdropped. However, this problem can also be solved. Jonathan Jogenfors said: "In the research report, we proposed some response measures, from simple technical solutions to rebuilding the entire machine." Currently, this research report has been published in the journal Science Advances. .
Copper substrate is the most expensive metal substrate, and its thermal conductivity is many times better than that of aluminum substrate and iron substrate. It is suitable for high-frequency circuits, areas with large changes in high and low temperature, and the heat dissipation and architectural decoration industries of precision communication equipment. The copper substrate circuit layer has great current carrying capacity and thermal aging resistance.
Heavy Copper PCB,Board Metal Substrate,Copper Substrate,Thermal Conductivity of Copper Board,Aluminum PCB Thermal Conductivity Huizhou Liandajin Electronic Co., Ltd , https://www.ldjpcb.com
June 19, 2024