Quantum mechanics is famous for saying that a tree falling in a forest when there's no one there doesn't make a sound. Quantum mechanics also says that if anyone is listening, it interferes with and changes the tree. And ...
Quantum Physics
Jun 2, 2011
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An international collaboration led by physicists of the University of Vienna shines new light on the question of the resources required for achieving quantum information processing. The scientists demonstrate that less demanding ...
Quantum Physics
Aug 6, 2012
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(Phys.org) —In a new study, physicists have teleported photonic qubits made of pairs of entangled photons that are generated by an LED containing an embedded quantum dot. The novel set-up has advantages compared to the ...
(Phys.org)—Demonstrating that limits were made to be broken, physicists have overcome what was previously considered to be a natural and universal limit on the efficiency of a quantum cryptography task called blind quantum ...
German hysicists at the Johannes Gutenberg University Mainz have developed a quantum interface which connects light particles and atoms.
Quantum Physics
May 27, 2010
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Physicists at the University of Calgary and at the Institute for Quantum Computing in Waterloo have published new research in Nature Physics which builds on the original ideas of Einstein and adds a new ingredient: a third ...
Quantum Physics
Dec 14, 2012
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Quantum computers, quantum cryptography and quantum (insert name here) are often in the news these days. Articles about them inevitably refer to entanglement, a property of quantum physics that makes all these magical devices ...
Quantum Physics
Apr 26, 2019
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Austrian physicists say a breakthrough in next-generation quantum cryptography could allow encrypted messages to be bounced off satellites, the British journal Nature reported Sunday.
Quantum Physics
May 3, 2009
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Quantum computing and quantum cryptography are expected to give much higher capabilities than their classical counterparts. For example, the computation power in a quantum system may grow at a double exponential rate instead ...
Quantum Physics
Aug 12, 2019
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Researchers at the University of California, Berkeley, have found a new way to harness properties of light waves that can radically increase the amount of data they carry. They demonstrated the emission of discrete twisting ...
Optics & Photonics
Feb 25, 2021
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Quantum cryptography, or quantum key distribution (QKD), uses quantum mechanics to guarantee secure communication. It enables two parties to produce a shared random bit string known only to them, which can be used as a key to encrypt and decrypt messages.
An important and unique property of quantum cryptography is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the key. This results from a fundamental aspect of quantum mechanics: the process of measuring a quantum system in general disturbs the system. A third party trying to eavesdrop on the key must in some way measure it, thus introducing detectable anomalies. By using quantum superpositions or quantum entanglement and transmitting information in quantum states, a communication system can be implemented which detects eavesdropping. If the level of eavesdropping is below a certain threshold a key can be produced that is guaranteed to be secure (i.e. the eavesdropper has no information about), otherwise no secure key is possible and communication is aborted.
The security of quantum cryptography relies on the foundations of quantum mechanics, in contrast to traditional public key cryptography which relies on the computational difficulty of certain mathematical functions, and cannot provide any indication of eavesdropping or guarantee of key security.
Quantum cryptography is only used to produce and distribute a key, not to transmit any message data. This key can then be used with any chosen encryption algorithm to encrypt (and decrypt) a message, which can then be transmitted over a standard communication channel. The algorithm most commonly associated with QKD is the one-time pad, as it is provably secure when used with a secret, random key.
This text uses material from Wikipedia, licensed under CC BY-SA
