In a nutshell, quantum cryptography is a process through which the field of quantum mechanics is used to make our data secure and less prone to hacking.
With the help of cryptography, we can secure data in such a way that only the person with the private key of the data can access it. Rather than using mathematics and prime numbers to create private keys, quantum cryptography relies on physics, and complicates the whole process to make it really hard to hack into a system. This is the main method used by the quantum cryptography algorithms to make the security of data possible.
Data secured with the help of quantum cryptography algorithms is impossible to copy without alerting the receiver or the sender. It can secure the data even against people who are using quantum computers to hack into your system.
Fiber optic network is used by quantum mechanics to transmit data in the form of light. every photon of light acts as a binary number to transmit the data. According to the principles of quantum mechanics, every photon of light can exist in more than one location at the same time. Moreover, if anyone tries to decrypt the data stored in the form of quantum particles, they cannot disturb it without destroying it. And, lastly, you can never copy all of the quantum particles at once. So, whenever a hacker will try to access your private key made through the quantum mechanics process, he will easily disturb the whole system without any benefit.
Since optical fibers are used to transmit data, light is used as the right medium, since it satisfies all the principles of quantum mechanics. The key distribution method using quantum mechanics is one of the best and the most secure data transmission system right now.