ami 27-03-22

Quantum Key Distribution and its Application

We have written on Quantum Key Distribution and received suggestions on complementing it with application of Quantum Key Distribution. This article tries to address that feedback.

What is Quantum Key Distribution (QKD)?

The concept of QKD was first proposed in 1970’s. It is believed that QKD is the only provable secure communication method (at least till now) because it uses physics, not math to encrypt data. QKD also known as Quantum Cryptography is a technology that employs quantum physics aimed to secure the distribution of symmetric encryption keys. QKD is the technology that can address the long prevailing confidentiality issue of secured data.

Long-lived Cryptosystem

Among the latest applications of QKD is the  long-term storage solution that aims to homogenize QKD with modern post quantum crypto technologies. The dynamics is changing so that quantum key distribution itself cannot protect confidentiality of data storage. For example, data relevant to human genome and health requires protection throughout its lifetime, which may be a century in time scale thanks to ever increasing life expectancy. Although research suggests that post quantum public key cryptography is expected to be resilient to quantum computers attacks, security for such a long time-scale cannot be guaranteed. So, the long-lived cryptosystems are foreseen to enable security for data storage applications.
The main pillars for long-lived Cryptosystem are as follows:
1. Confidentiality: The data should be accessible only to authorized parties. Theoretically secure encryption (not computational) should be used on the information
2. Integrity: The data should remain unaltered. Signature and authentication schemes should be employed
3. Availability: The data should be available whenever required. Redundant data backup and fail safe mechanisms needs to be in place
4. Functionality: The data can be processed without decryption. Fully homomorphic encryption is expected

Applications of Quantum Key Distribution

The articles touch on the following two QKD applications:
1. QKD Networks
2. QKD Platforms

Quantum Key Distribution Networks:

QKD networks are custom-built (and generally proprietary) networks for secure and seamless transfer of data and information. It is not surprising that QKD has been deployed in many (links and networks) areas  and prominent among them are:
1. Defense Advanced Research Projects Agency (DARPA) – The DARPA Quantum Network pioneered the deployment of QKD in a metropolitan network and operates with 10 optical nodes across Boston and Cambridge, Massachusetts
2. Secure Communication based on Quantum Cryptography (SECOQC) – SECOQC is a European project that integrated several QKD systems into one quantum back bone (QBB) network. It is developing a cross-platform interface to demonstrate (to start with) the encryption of voice transmission
3. SwissQuantum – The SwissQuantum network is believed to be the first international QKD network. A quantum layer is implemented with commercial QKD devices (ID Quantique, id5100). The layer is composed of the following three QKD point-to-point links:
        a. Unige – CERN
        b. CERN – Hepia
        c. Hepia – Unige
4. Chinese networks – Though not the first one, the Chinese QKD network is the most advanced globally. It comprises over 2000 kilometers by fiber optics covering over four major cities of China (Shanghai, Hefei, Jinan and Beijing), and a 2600 kilometers satellite link between two observatories. The Chinese network spans around 4600 kilometers

Quantum Key Distribution Platforms:

The QKD networks are based on trusted nodes. These nodes themselves are physically protected vaults and keys from connected QKD links are securely stored and managed in these vaults. QKD networks are enterprise grade and connect two closely knit organizations. The security is tightly coupled as specifications are strictly confidential making it impossible to interconnect (external) systems.

This problem can be solved if the keys and the identifiers are properly managed in the trusted nodes thereby enforcing compliance among different QKD networks. The QKD platform plays an important role in supply and storage of keys to various applications. It can result in enhanced security of applications as well as seamless connection and security of links across QKD networks of many different organizations.

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