# Quantum Computers and Nanotechnology Make Quantum Cryptography Necessary, A Basic Explanation of Quantum Cryptography

## Topics Covered

Background

Brute Force Code Breaking

Quantum Cryptography

Heisenberg Uncertainty Principle

Applications of Quantum Cryptography

## Background

Quantum computing and quantum computers are in advanced stages of development due to recent nanotechnology advances in these areas. These computers promise to be so fast and powerful that our modern supercomputers will be little more than toys in years to come. The problem is that their sheer capacity for processing data means that they will likely be able to readily crack even the most advanced encryption methods through brute force.

## Brute Force Code Breaking

There is nothing elegant or subtle about brute force code breaking. It simply means trying millions of different combinations in order to come up with the right one. The more digits in a password for example, requires more attempts at guessing correctly. When the number of permutations is measured in the millions or billions, the time taken to break a code using brute force can be excessive. However a quantum computer can work at such high speed it could crack an encryption code in seconds, whereas current computers may take hundreds of years to do the same job.

## Quantum Cryptography

Fortunately quantum cryptography has arrived as a reality in advance of quantum computers. The way quantum cryptography works relies upon an interesting twist of quantum physics known as the Heisenberg Principle.

## Heisenberg Uncertainty Principle

The Heisenberg Uncertainty Principle is based on the idea that by simply looking at a tiny particle like a photon, you change it permanently.

This means that you if you use a the state of a photon to generate a cryptography key to protect data transmissions, then that key is altered and the data rendered unreadable if someone tries to eavesdrop on the transmission.

Athough it is single photons that are being dealt with, the keys are generated at a rate of hundreds of them every second. This makes breaking the encryption impossible.

## Applications of Quantum Cryptography

Quantum cryptography systems are already used by some government agencies, large banks, telecommunications companies and other corporations who handle sensitive or military data. Commercial quantum cryptographic systems are available from a range of companies including MagiQ, id Quantique and NEC.

Source: AZoNano