How does qkd work

The network currently connects back office operations in New Jersey to Manhattan, but plans are in place to expand it across the U. One of the challenges for QKD is the distance over which the photons can travel, which is typically around km.

Quantum Xchange developed a way to increase the range of QKD transmissions beyond km through the use of its proprietary Phio TX technology. This extends the range by decrypting the transmissions into classical bits and then encrypting them again with quantum bits to transmit further on the fiber network.

As long as a continuous path of trusted exchanges links two widely separated endpoints, those endpoints can still share quantum-derived key information over this much longer path.

Between consecutive nodes, key information is protected by the same quantum mechanisms as a singular QKD system. While within a node, key information is protected by encryption with locally-generated keys and a secure boundary that prevents tampering.

Since Phio TX can include a number of QKD endpoints, the network topologies that can be realized by the trusted exchanges are essentially limitless. About me Nullam nec elit quis tortor aliquam venenatis a ac enim. Quisque iaculis orci ante, eu tincidunt arcu tempor vitae. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Suspendisse malesuada ante dictum, auctor elit semper, semper dui. June 10, by Gert Grammel. In response to a letter from German physicist and mathematician Max Born, who was instrumental in the development of quantum mechanics, Einstein said: Quantum mechanics is very impressive.

QKD exploits two fundamental attributes of quantum mechanics: A quantum key in the form of entangled qubits can exist at two places at the same point in time. Every attempt to measure a qubit alters the characteristic information of qubits at both places and can immediately be identified. This also implies that a qubit cannot be copied. So, how does this look in practice? Additionally, QKD architectures leverage three communication channels: The Crypto Channel : Quantum channels are not well suited to transport anything other than random qubits.

To make use of them, quantum keys are shared in an information theoretical safe manner at a rather low bitrate. The keys are subsequently fed into cryptographic algorithms which encrypt massive amounts of data in a separate channel. The Key Exchange Channels : These are the channels by which the devices at the ends of the quantum channel can communicate quantum keys to the devices at the ends of the crypto channel.

In other words, this is how quantum keys are exploited. The Quantum Channel: Since quantum mechanics describe objects in the physical world, such as photons, devices that deal with quantum keys cannot be virtualized. To maintain the quantum information, qubits need to be communicated by physical transmitters and receivers.

In both cases, there are vulnerabilities when initializing communication. Symmetric key systems often rely on physical sharing of keys — some financial institutions use actual couriers with portable storage devices — to bootstrap. Or they may rely on a connection secured using an asymmetric system to share the encryption key needed for subsequent use. For high-value transactions like inter-bank communication and election result transmission, the benefits of QKD are sometimes worth the cost.

In a research effort directed at finding ways to secure the power grid, teams at Oak Ridge and Los Alamos National Laboratories have demonstrated the first successful use of QKD between different implementations.

The University of Bristol has also just published research on doing something similar to help secure multi-vendor 5G wireless networks. While harder than QKD, it will eventually be possible to encrypt data using quantum computing techniques that are particularly resistant to eavesdropping and various other forms of hacking. The most popular approach currently is the Kak protocol. The double-lock protocol is remarkably simple. They also want to know if anyone is successfully eavesdropping on their communication channel.

To do this they trade locks in a three-step process. Our cybersecurity infrastructure requires two different functions: authentication and confidentiality. Authentication allows distant users to trust their counterpart and validate the content of their exchanges.

It is mostly implemented by public-key signature schemes. Confidentiality is required for any exchange of private information. It is often performed in a two-step process. First the users have to exchange a common secret key. This relies on another public-key protocol, the key exchange mechanism.

The secret key is then used in a symmetric key encryption scheme. Both functions therefore depend on similar cryptographic techniques, known as asymmetric or public-key cryptography. Cybersecurity is much more than the underlying cryptography. All current hacks and security failures do not come from a weak cryptography, but rather from faulty implementation, social engineering and the like.

Today, we trust the cryptography, and fight to get the implementation right. Unfortunately, this is about to change. The point of cryptographic vulnerability today is public-key cryptography, based on algorithms such as RSA or Elliptic Curve, which are used both to authenticate data and to securely exchange data encryption keys. The very processing power of the quantum computer can solve these mathematical problems exponentially faster than classical computers and break public-key cryptography.

This means that the currently used public-key cryptosystems are not appropriate to secure data that require long-term confidentiality.

An adversary could indeed record encrypted data and wait until a quantum computer is available to decrypt it, by attacking the public keys. The greatest threat is to public cryptography — or asymmetric algorithms — used for digital signatures and key exchange.

There are already quantum algorithms, such as the famous Shor algorithm, which can break RSA and Elliptic Curve algorithms, once a universal quantum computer is available. Another famous quantum algorithm, the Grover algorithm, attacks symmetric cryptography.

Fortunately, Grover can be countered by a simple expansion of the key size.