Quantum computing is based on quantum mechanics, which governs how nature works at the smallest scales. The smallest classical computing element is a bit, which can be either 0 or 1. The quantum equivalent is a qubit, which can also be 0 or 1 or in what’s called a superposition — any combination of 0 and 1. Performing a calculation on two classical bits (which can be 00, 01, 10 and 11) requires four calculations. A quantum computer can perform calculations on all four states simultaneously.

This scales exponentially: 1,000 qubits would, in some respects, be more powerful than the world’s most powerful supercomputer.

In this digital-oriented world, hackers are evolving in parallel to technological advancements. Fortunately, engineers, mathematician and physicists are simultaneously working on innovative concepts that harness the progression of classical encryption methods. New devices are utilizing principles of quantum physics and deploying sophisticated and powerful algorithms for safe communication.

**What is cryptography?**

Cryptography is a means of securing data and information to dodge malicious hackers. Thanks to cryptographic methods, everything from web conferences to individual browsing history remain privileged and safe. Data are protected using algorithms that require a unique key for decryption and encryption. Utilization of the same private key, i.e. a specific string of bits for decryption and encryption, is called symmetric cryptography. Utilization of public keys for encryption and private keys for decryption — each of which are created by algorithm-fuelled random number generators — is called asymmetrical cryptography.

Genuine randomness is considered unachievable by purely classical means, but can be accomplished with the added application of quantum physics.

**Quantum key distribution**

There are two methods by which large-scale quantum and classical computers can obscure private information.

• Method #1: Recover the key generated during the key agreement phase.

• Method #2: Interrupt the encryption algorithm.

Quantum key distribution (QKD) is a quantum cryptographic primitive designed to generate unbreakable keys. QKD ensures key agreement, including well-known BB84 and E91 algorithms. In 2017, a Chinese team successfully demonstrated that satellites can perform safe and secure communications with the help of symmetrical cryptography and QKD.

Still, it’s clear that QKD alone can’t satisfy all protection requirements, but there are other mechanisms for security enhancement by utilizing “quantum-safe” encryption algorithms based on solving mathematical problems instead of laws of quantum physics.

**An optimistic view of quantum-computing obstacles**

The most immediate challenge is accomplishing the most sufficient number of fault-tolerant qubits to boost quantum computing’s computational promises. Tech giants such as Google, Amazon, IBM and Honeywell are taking this problem under consideration and investing in it to come up with a solid solution.

Currently, quantum computers are programmed for individual quantum logic gates. This might be acceptable for small-scale quantum computers, but less so once we come across a large number of qubits.

Organizations such as IBM and Classiq are developing more and more abstract layers in the programming stack, allowing developers to nurture incredible and powerful quantum applications to provide solutions to real-world problems.

For the implementation of complex problems including error-correction schemes, organizations need to prove that they can control numerous qubits. This control must have low latency and it must come from adaptive-feedback control circuits based on CMOS. Ultimately, the issue of “fan-out” must be addressed. The question that needs to be answered is how to pace up a number of qubits within a quantum chip. Multiple lasers or control wires are currently required, but it’s hard to see how we can develop multiple qubit chips with millions of wires connected to the circuit board or coming out of the cryogenic measurement chamber.

**Applying quantum computing to cybersecurity**

In recent years, researchers and analysts have been striving for the development of quantum-safe encryption. According to American Scientist, the United States National Institute of Standards and Technology is presently evaluating 69 new methods known as “post-quantum cryptography,” or PQC. Quantum computing offers an eminent, potential solution to cybersecurity and encryption threats. Any security-forward organization ought to develop an understanding of crypto agility.

Quantum revolution is uncertain. While the intense impact of extensive fault-tolerant quantum computers may be far off, near-time quantum computers still present enormous advantages in enhancing levels of communication privacy and security. All organizations must consider developing innovative strategies around the long-term benefits and risks of quantum technology and computing, and be ready for the forthcoming quantum revolution.

Today’s classical computers use two primary classes of algorithms for encryption: symmetric and asymmetric.

• In symmetric encryption, the same key is used to encrypt and decrypt a given piece of data. The Advanced Encryption Standard (AES) is an example of a symmetric algorithm. Adopted by the US government, the AES algorithm supports three key sizes: 128 bits, 192 bits, and 256 bits. Symmetric algorithms typically are used for bulk encryption tasks, such as enciphering major databases, file systems, and object storage.

• In asymmetric encryption, data is encrypted using one key (usually referred to as the public key) and is decrypted using another key (usually referred to as the private key). Although the private key and public key are different, they are mathematically related. The widely employed Rivest, Shamir, Adleman (RSA) algorithm is an example of an asymmetric algorithm. Even though it is slower than symmetric encryption, asymmetric algorithms solve the problem of key distribution, which is an important issue in encryption.

**Quantum risks to cybersecurity**

The advent of quantum computing will lead to changes to encryption methods. Currently, the most widely used asymmetric algorithms are based on difficult mathematical problems, such as factoring large numbers, which can take thousands of years on today’s most powerful supercomputers.

However, research conducted by Peter Shor at MIT more than 20 years ago demonstrated the same problem could theoretically be solved in days or hours on a large-scale quantum computer. Future quantum computers may be able to break asymmetric encryption solutions that base their security on integer factorization or discrete logarithms.

Although symmetric algorithms are not affected by Shor’s algorithm, the power of quantum computing necessitates a multiplication in key sizes. For example, large quantum computers running Grover’s algorithm, which uses quantum concepts to search databases very quickly, could provide a quadratic improvement in brute-force attacks on symmetric encryption algorithms, such as AES.⁵

To help withstand brute-force attacks, key sizes should be doubled to support the same level of protection. For AES, this means using 256-bit keys to maintain today’s 128-bit security strength.

Even though large-scale quantum computers are not yet commercially available, initiating quantum cybersecurity solutions now has significant advantages. For example, a malicious entity can capture secure communications of interest today. Then, when large-scale quantum computers are available, that vast computing power could be used to break the encryption and learn about those communications.

Eclipsing its potential risks, quantum cybersecurity can provide more robust and compelling opportunities to safeguard critical and personal data than currently possible. It is particularly useful in quantum machine learning and quantum random number generation.

**Why create a Quantum computer?**

The reasons are not only to improve the processing capacity and solve the problems that cannot be done with traditional computers. In the last 20 years, the complexity and number of transistors in a single CPU have increased exponentially. It seems that we found the limits of the transistor technology in the integrated circuit.

The extreme miniaturization of electronic doors is causing the effects of a phenomenon that become much more significant, such as Electromigration and the Sub-threshold. These obstacles are, among other factors, that make researchers study new computing methods, such as the quantum computer.

**Preparing for The Quantum Future**

The quantum revolution is upon us. Although the profound impact of large-scale fault-tolerant quantum computers may be a decade off, near-term quantum computers will still yield tremendous benefits.

We are seeing substantial investment in solving the core problems around scaling qubit count, error correction and algorithms. From a cybersecurity perspective, while quantum computing may render some existing encryption protocols obsolete, it has the promise to enable a substantially enhanced level of communication security and privacy.

Organizations must think strategically about the longer-term risks and benefits of quantum computing and technology and engage in a serious way today to be ready for the quantum revolution of tomorrow. If you want more updates on latest technologies, please follow deeptechknowledge.com where we post about the upcoming technologies and their uses.