Quantum cryptography guarantees “unbreakable” security by hiding information in light particles or photons emitted from a laser pointer. In this form of cryptography, quantum mechanics is used to randomly generate a key. The sender, often referred to as Alice, sends the key through polarized photons with different polarization directions. The recipient, often referred to as Bob, uses a photon detector to measure the polarization direction of the photon, and the detector then converts the photon into bit information. Assuming that Bob uses the correct photon detector in the correct order, he can Get the key.
The advantage of quantum cryptography is that if an attacker tries to intercept Alice and Bob’s messages, the cryptography will change itself due to the characteristics of quantum mechanics. Since it was first proposed in the 1980s, quantum cryptography has given people the possibility of achieving unbreakable security. “In theory, an attacker might have all the power under the laws of physics, but they still can’t crack this kind of password,” said the first author of the paper, LucianComandar, who is from the Engineering Department of Cambridge University and the Toshiba Cambridge Research Laboratory. PhD students.
However, when trying to build a usable system, the problem of quantum cryptography arises. In reality, this is a game that goes back and forth: creative attacks against different components of the system are constantly being developed, and corresponding countermeasures against attacks are also constantly developing. The most frequently hacked component is the photon detector, which is usually the most vulnerable and complex component due to its high sensitivity and complex green laser pointer design. In response to the attack detector, the researchers developed a new quantum cryptographic protocol called measurement device-independent quantum key distribution.