Quantum Cryptography: In Security Aspects

1. Introduction

Information Technology and Communication has undergone development remarkably in the past years. To secure the communication among the parties from adversary the technique that is used is called as Cryptography. Main aim of Cryptography is to ensure Confidentiality (Third party cannot interpret the message or data that is sent between intended users), Authentication (Message is received from authentic user), Integrity (Message is not altered in between). This is achieved by sending secret message that requires the creation of the key that is sent to the other party. This key can be stolen or can be copied by the third party. Public key Cryptography can involve complex mathematical calculation that makes the process slower. To overcome these limitations and to make the communication more secure quantum Cryptography is used. Quantum cryptography was built in late 1960, when conjugate coding was written by Stephen Wiesner. Quantum Cryptography is an approach to transmit the information securely by applying the concept of quantum physics. Mathematical cryptography algorithms like RSA and elliptic curve cryptography are widely used today. There is a lack of security in these algorithms. There is a threat to sensitive information that needs high degree of security by these prevailing mathematical cryptosystems. The security of quantum cryptography relies more on physics including quantum mechanics and statistics rather than on solving mathematical problems. Well known application of quantum cryptography is quantum key distribution (QKD) that is used to establish communication by generating cryptographic keys. Moreover, it is based on Heisenberg Uncertainty principle that ensures the security and prevents from eavesdropping. Even if there is any case of eavesdropping of key that occurs by adversary, the two parties communicating with each other can come to know easily about this due to some discrepancies. QKD device comprise of photon transceiver along with electrical component. There are various limitations of QKD as well like the range is limited from 50 to 100 km as photons are easily lost during communication. Quantum Computing follows the principles of superposition, entanglement and quantum mechanics. Superposition refers to as making new moves while processing information. Quantum Superposition states that 2 particles can be at distinct locations at the same time. It is not feasible to observe it in real world as it exists in subatomic particles. Entangled particles refer to the state where the particles cannot be defined or described individually, without the consideration of other particles. In Quantum mechanics qubits are used rather than simple bits on which quantum cryptography is highly dependent on.