## How Quantum Computing will affect Current Encryption Methods

#### What is Quantum Computing?

Quantum computers work quite differently from traditional “classic” computers. Classic computers process information in **binary bits****,** in the form of ones *or* zeros. However quantum computers process information through quantum bits or “** qubits**”, which can be either a one, a zero or both at the same time. This is known as “**Superposition**” and is the heart of quantum computing** .** The ability of quantum computing’s superposition allows significantly higher computational power.

**What is Cryptography?**

Cryptography is the practice of securing digital communications – protecting data and information from anyone who is not meant to see it.

**Cryptography** uses algorithms to change ordinary text into encrypted text and to decrypt the encrypted text back into ordinary text. In modern times, there are 2 forms of cryptography – symmetric cryptography and asymmetric cryptography.

The main differences between these 2 forms of cryptography are their level of security and the “keys” that they use.

**The current State of Cryptography**

**Symmetric cryptography **is the simplest modern form of cryptography. It uses a single key, which both the sender and recipient must have, to encrypt and decrypt the data. This system can be vulnerable, as it means sharing the key in which the data is encrypted, and if an unwanted third party manages to get hold of the private key, they too can decrypt and access the data. And thus, asymmetric cryptography was developed.

Currently, the most widely used method of cryptography is **asymmetric cryptography **or public-key cryptography. This is because, unlike symmetric cryptography, it does not require the sender to find a secure way in which to give the “private key” to the recipient, in order to decrypt the encrypted data.

Asymmetric cryptography uses the **RSA algorithm** to generate each user with a public key and a private key. The public key can then be shared and used to encrypt the data, and only the holder of the private key will be able to decrypt the data. The RSA algorithm makes use of 2 large prime numbers and an auxiliary value to create the public key. The security of and difficulty of breaking this form of encryption lies within factoring the product of 2 large prime numbers.

**How Quantum Computing will Affect Cryptography?**

Because of the computational power that quantum computers are capable of, the commercial availability of quantum processors could leave the current state of cryptography completely obsolete. As stated above, the current use of asymmetric cryptography and the RSA algorithm relies on how difficult and time consuming it is for standard computers and processors to compute the factors of the 2 large prime numbers used to create the keys. As an example, there was a 193 digit number produced, which took 80 2.2GHz computers 5 months to factor the number. However, a quantum computer of the same size, would theoretically only take 17 seconds to factor the number.

With these realisations, there have already been 2 solutions theorised, including a public-key system secure enough to defend even against quantum computers, and the second being **quantum cryptography**.

We will have to wait and see how quantum computing develops over the coming years and how it might impact our entire digital world.