Cyber security is a huge issue in a world in which much of our lives are increasingly lived online. Cyber security is a broad term referring to all technologies, processes, systems, software, hardware and other applications that are designed to prevent computers from forms of malicious attack.

Recently, blockchain technology began to be widely adopted by many as a secure system for data security. Blockchain is thought to be secure as the underlying cryptography is so hard to break that conventional computers would be incapable of doing so. However, should quantum computing come into play, it is possible that even this type of cryptographic shield could be shattered, potentially even in a matter of days.

Quantum computing was once though to be an impossible dream, but over the past ten years or so it has become more probable that quantum computing may become functionally possible within the next decade.

Domen Zavrl has taken courses in cryptography at the prestigious Stanford University and has two PhD qualifications in the fields of Applied Macroeconomics and System Dynamics. A brief explanation of what quantum computing is can be found in the PDF attachment to this post.

While quantum computing could bring many benefits, it also raises serious concerns about security.

Post-Quantum Cryptography

With quantum computing looming ever larger in our futures, scientists and computer engineers are now exploring post-quantum cryptographical methods that will be able to resist an attack from a quantum computer.

Encryption in its current format which cannot easily be broken by traditional computers could easily be beaten by a functioning quantum computer, which would be capable of performing tasks thousands of times faster than classical supercomputers.

The potential advantages of quantum computing are such that, almost as soon as it arrives, it will become commonplace. This means that organisations need to be thinking about investment in quantum-proof cryptography now, to protect data and systems in the future.

How Encryption Works

Encryption underpins online security across almost everything we use on the internet, from messaging services to online banking. Encryption works by scrambling data using algorithms before sending it, then providing the recipient with a decryption key.

The nature of encryption means that it is easy to compute when sending the information where it needs to go, but extremely difficult if not impossible to invert using current technology. Algorithms use mathematical formulas and functions to encrypt messages. Calculating the product of two numbers when sending in one direction is simple. However, to invert requires factoring, often using large prime numbers with several hundred digits.

There is currently no method for doing this easily, which is why encryption works. Factoring could become a scalable problem that is solved as soon as the first quantum computer is developed, which would make all modern encryption methods ineffective and open to attack.

The infographic attachment looks at some of the approaches to post-quantum cryptography being explored by scientists.

Quantum Computing and Blockchain

Quantum computing does not necessarily present a threat to the concept of blockchain, but unless post-quantum security measures are introduced, it could threaten projects using blockchain technology.

Blockchains and the cryptography that underpins them cannot be broken by any currently existing computers, but the advent of quantum computers could result in systems powerful and fast enough to break the encryptions. This threat can be eradicated through the development of quantum-resistant blockchains and the use of quantum computers for nodes within the distributed ledger systems.

A brief introduction to distributed ledger systems can be seen in the short video attachment.