Cryptography is the science that converts ordinary information into a coded form. This is a means of keeping information safe and secure from unwanted users. When such cryptography uses quantum mechanical properties to deny access to malicious actors then it is known as quantum cryptography.
Hence, it serves the same purpose as classical cryptography. It seeks to keep important information secret from unintended users. The only difference is that it does so in a far more secure manner as compared to classical computing.
Typically, cryptographic techniques use mathematical concepts and algorithms. Most often these tasks include generation of cryptographic keys and digital signatures, securing data privacy and confidentiality of communications.
For example, currently, RSA and ECC encryption algorithms form the basis of modern day cryptographic practices. These, however, can be broken white easily by quantum computers.
Quantum cryptography relies on one of the most fundamental tenets of quantum science — the Heisenberg uncertainty principle. A gross and simplified version is that the observation of any arbitrary and unknown quantum state leads to the collapse of its wave function.
Quantum key distribution (QKD) is one of the most widely known applications of quantum cryptography. This process takes the existing step in cryptography of sharing a random and secure key between two communicators and transforms it into an almost unbreakable (well unbreakable at least 2021 standards) code by using quantum computing. Hence, QKD does not encrypt the key, but ensures security of the communication process.
Quantum-safe cryptography, on the other hand, often tries to solve the same problem of security using alternate approaches to existing solutions in classical computing along with a safety layer of quantum computing.
A hybrid approach, therefore, is the best bet for the coming years in terms of combatting the threat to enterprise security from ever evolving novel technologies.
