Quantum Cryptography: Basic Principles and Methodology

Heisenberg Uncertainty Principle

In 1927, a German researcher Werner Heisenberg proposed Heinsenberg's principle of uncertainty which states that it is not possible to observe and calculate two properties at a time of an object and always shows uncertainty. For an instance, consider an object with the properties like position (x) and moving with the velocity (p) cannot be calculated simultaneously because it does not make sense to exist. A person's weight is not determined by his height. This idea works when we try to observe and calculate anything. The Heisenberg uncertainty prevents the intruder when applying this principle to protons because the proportions are affected by the polarity of the photon.

Photon Polarization Principle

This principle uses non-cloning methods to ensure that the attacker does not copy unique quantum bits. This creates a quantum state which cannot be recognized and distorts other information if anyone tries to measure the bit. Quantum cryptography is a solution for cryptographic functions that cannot be performed with classical cryptography. It is the safest solution to the problem in the key exchange process (Bhatt & Sharma, 2019).

The Contribution of the Pioneers

It seems that history is about to repeat itself for computers this time. Quantum cryptography began the evolution of quantum computers and remembered the history of a research paper written by Einstein's with the title “Theory of Relativity”. The paper rewrote Newton's laws basic principles of physics and changed the world's understandings of physics. Quantum computer rewrites all computer concepts right from scratch. The computer is defined based on dimensions like software, hardware, database, and applications. But the Quantum computers are in the process of switching to older computers and gaining the level called Quantum Supremacy. This happened due to the contribution of its pioneers.

Quantum computing is known as 'quantum circuit' which works like programs, specifying a set of quantum machine operations to run. In the late 1960s, two researchers Stephen Weissner and Gilles Brassrd of Columbia University tried to solve the problems of classical cryptography very first time. They wrote a research paper for IEEE Information Theory Society which was rejected but then published in SIGACT News in the early 1980s.

Stephen Weissner and Gilles Brassrd proposed the idea of the Conjugate Code. Conjugate code is a way to encode and transmit two messages with two different forms. The concept of photon polarization is used in a linear and circular form where it is possible either to receive and decode messages on the safe and two stages secured channel. They titled the protocol “Quantum Key Distribution Protocol” which is widely known as the concept QKD. As the protocol was proposed in the year 1984, the method became famous as Bennett and Bassard 1984 (BB84) method.

As QKD is a two-stage protocol, it has certain limitations. The revised three-stage protocol is then proposed by an Indian-US-based computer scientist Subhash Kak in 2005 which describes a single photon transmission from sender to receiver. This is different from the previous QKD key exchange and explains the continuous and without break exchange of keys. This three-stage QKD protocol then becomes the base of next-generation computers.