Amid steep gains in value and wild headlines, its easy to forget cryptocurrencies and blockchain arent yet mainstream. Even so, fans of the technology believe blockchain has too much potential not to have a major sustained impact in the future.

But as is usually the case when pondering whats ahead, nothing is certain.

When considering existential threats to blockchain and cryptocurrencies, people generally focus on increased regulation. And this makes sense. In the medium term, greater regulation may stand in the way of cryptocurrencies and wider mainstream adoption. However, there might be a bigger threat further out on the horizon.

Much of blockchains allure arises from its security benefits. The tech allows a ledger of transactions to be distributed between a large network of computers. No single user can break into and change the ledger. This makes it both public and secure.

But combined with another emerging (and much hyped) technology, quantum computing, blockchains seemingly immutable ledgers would be under threat.

Like blockchain, quantum computing has been making progress and headlines too.

The number of quantum computing companies and researchers continues to grow. And while there is a lot of focus on hardware, many are looking into the software as well.

Cryptography is a commonly debated topic because quantum computing poses a threat to traditional forms of computer security, most notably public key cryptography, which undergirds most online communications and most current blockchain technology.

But first, how does computer security work today?

Public key cryptography uses a pair of keys to encrypt information: a public key which can be shared widely and a private key known only to the keys owner. Anyone can encrypt a message using the intended receivers public key, but only the receiver can decrypt the message using her private key. The more difficult it is to determine a private key from its corresponding public key, the more secure the system.

The best public key cryptography systems link public and private keys using the factors of a number that is the product of two incredibly large prime numbers. To determine the private key from the public key alone, one would have to figure out the factors of this product of primes. Even if a classical computer tested a trillion keys a second, it would take up to 785 million times longer than the roughly 14 billion years the universe has existed so far due to the size of the prime numbers in question.

If processing power were to greatly increase, however, then it might become possible for an entity exercising such computing power to generate a private key from the corresponding public key. If actors could generate private keys from corresponding public keys, then even the strongest forms of traditional public key cryptography would be vulnerable.

This is where quantum computing comes in. Quantum computing relies on quantum physics and has more potential power than any traditional form of computing.

Quantum computing takes advantage of quantum bits or qubits that can exist in any superposition of values between 0 and 1 and can therefore process much more information than just 0 or 1, which is the limit of classical computing systems.

The capacity to compute using qubits renders quantum computers many orders of magnitude faster than classical computers. Google showed a D-Wave quantum annealing computer could be 100 million times faster than classical computers at certain specialized tasks. And Google and IBM are working on their own quantum computers.

Further, although there are but a handful of quantum computing algorithms, one of the most famous ones, Shors algorithm, allows for the quick factoring of large primes. Therefore, a working quantum computer could, in theory, break todays public key cryptography.

Quantum computers capable of speedy number factoring are not here yet. However, if quantum computing continues to progress, it will get there eventually. And when it does, this advance will pose an existential threat to public key cryptography, and the blockchain technology that relies on it, including Bitcoin, will be vulnerable to hacking.

So, is blockchain security therefore impossible in a post-quantum world? Will the advent of quantum computing render blockchain technology obsolete?

Maybe, but not if we can develop a solution first.

The NSA announced in 2015 that it was moving to implement quantum-resistant cryptographic systems. Cryptographers are working on quantum-resistant cryptography, and there are already blockchain projects implementing quantum-resistant cryptography. The Quantum Resistant Ledger team, for example, is working on building such a blockchain right now.

What makes quantum-resistant or post-quantum cryptography, quantum resistant? When private keys are generated from public keys in ways that are much more mathematically complex than traditional prime factorization.

The Quantum Resistant Ledger team is working to implement hash-based cryptography, a form of post-quantum cryptography. In hash-based cryptography, private keys are generated from public keys using complex hash-based cryptographic structures, rather than prime number factorization. The connection between the public and private key pair is therefore much more complex than in traditional public key cryptography and would be much less vulnerable to a quantum computer running Shors algorithm.

These post-quantum cryptographic schemes do not need to run on quantum computers. The Quantum Resistant Ledger is a blockchain project already working to implement post-quantum cryptography. It remains to be seen how successful the effort and others like it will prove when full-scale quantum computing becomes a practical reality.

To be clear, quantum computing threatens all computer security systems that rely on public key cryptography, not just blockchain. All security systems, including blockchain systems, need to consider post-quantum cryptography to maintain data security for their systems. But the easiest and most efficient route may be to replace traditional systems with blockchain systems that implement quantum-resistant cryptography.

Disclosure: The author owns assorted digital assets. The author is also a principal at Crypto Lotus LLC, a cryptocurrency hedge fund based out of the San Francisco Bay Area, and an advisor at Green Sands Equity, both of which have positions in various digital assets. All opinions in this post are the authors alone and not those of Singularity University, Crypto Lotus, or Green Sands Equity. This post is not an endorsement by Singularity University, Crypto Lotus, or Green Sands Equity of any asset, and you should be aware of the risk of loss before trading or holding any digital asset.

Image Credit: Morrowind /Shutterstock.com

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- Superconducting quantum computing - Wikipedia - October 6th, 2019
- Quantum computing | MIT News - October 6th, 2019
- How Do Quantum Computers Work? - sciencealert.com - October 2nd, 2019
- What is Quantum Computing? - Definition from Techopedia - October 2nd, 2019
- How Quantum Computers Work | HowStuffWorks - September 5th, 2019
- Quantum computing could change everything, and IBM is ... - May 15th, 2019
- Quantum Computing - Intel - April 29th, 2019
- IBM expands universities in its quantum computing research ... - April 25th, 2019
- Quantum computing is a marathon not a sprint | VentureBeat - April 22nd, 2019
- The CIO's Guide to Quantum Computing - Smarter With Gartner - April 19th, 2019
- This Startup Just Raised $21 Million To Bring Quantum ... - April 18th, 2019
- What is Quantum Computing ? Top 18 Quantum Computing ... - April 6th, 2019
- The promise of quantum computing - businessinsider.com - March 27th, 2019
- Quantum computing is coming: Heres why we need to get our ... - March 23rd, 2019
- Quantum computing will break your encryption in a few ... - March 21st, 2019
- Microsoft has formed a coalition to promote quantum computing ... - March 19th, 2019
- Quantum computing for everyone | Michael Nielsen - March 12th, 2019
- Ask a Techspert: What is quantum computing? - blog.google - March 6th, 2019
- IBM hits quantum computing milestone, may see 'Quantum ... - March 6th, 2019
- Its Time You Learned About Quantum Computing | WIRED - March 6th, 2019
- Microsofts quantum computing network takes a giant leap ... - March 2nd, 2019
- When Will Quantum Computing Have Real Commercial Value ... - February 25th, 2019
- The Case Against Quantum Computing - IEEE Spectrum - February 22nd, 2019
- How Does Quantum Computing Work? - ExtremeTech - January 31st, 2019
- Quantum technology - Wikipedia - January 23rd, 2019
- CES 2019: IBM's Q System One Is the Rock Star Quantum ... - January 13th, 2019
- Quantum Computing | The MIT Press - January 11th, 2019
- IBM thinks outside of the lab, puts quantum computer in a box - January 11th, 2019
- IBM unveils its first commercial quantum computer - January 9th, 2019
- A new type of quantum computer has smashed every record ... - December 21st, 2018
- China bet big on quantum computing. Now the US races to ... - October 26th, 2018
- US takes first step toward a quantum computing workforce ... - September 17th, 2018
- China bet big on quantum computing. Now the ... - money.cnn.com - September 17th, 2018
- The reality of quantum computing could be just three years ... - September 12th, 2018
- The quantum computing race the US cant afford to lose - September 3rd, 2018
- Quantum Computing | USRA - August 30th, 2018
- What Is Quantum Computing? The Complete WIRED Guide | WIRED - August 22nd, 2018
- Quantum Computing Market Research Report- Forecast 2022 | MRFR - August 1st, 2018
- Two Quantum Computing Bills Are Coming To Congress - July 5th, 2018
- Senate bills would make quantum computing a priority - June 10th, 2018
- What is quantum computing? - Definition from WhatIs.com - February 5th, 2018
- The Era of Quantum Computing Is Here. Outlook: Cloudy ... - January 26th, 2018
- IBM puts its quantum computer to work in relaxing, nerdy ASMR ... - January 8th, 2018
- Quantum computing is going to change the world. Here's what ... - January 8th, 2018
- What is Quantum Computing? | SAP News Center - December 23rd, 2017
- Quantum Computing Explained | What is Quantum Computing? - December 21st, 2017
- New silicon structure opens the gate to quantum computers - December 14th, 2017
- Microsoft offers developers a preview of its quantum ... - December 12th, 2017
- Quantum Computing Is the Next Big Security Risk | WIRED - December 8th, 2017
- Yale Professors Race Google and IBM to the First Quantum ... - November 16th, 2017
- IBM's processor pushes quantum computing ... - engadget.com - November 16th, 2017
- Quantum computing - news.microsoft.com - November 1st, 2017
- Intel Takes First Steps To Universal Quantum Computing - October 13th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - October 13th, 2017
- quantum computing - engadget.com - October 13th, 2017
- Quantum Computing | Intel Newsroom - October 13th, 2017
- What will you actually use quantum computing for? | ZDNet - October 11th, 2017
- Here's what quantum computing is and why it matters - October 6th, 2017
- Microsoft just upped its multi-million bet on quantum computing - ZDNet - September 7th, 2017
- Microsoft's Aussie quantum computing lab set to scale up next-gen ... - ARNnet - September 7th, 2017
- An Entirely New Type of Quantum Computing Has Just Been Invented - Futurism - September 7th, 2017
- Quantum computing event explores the implications for business - Cambridge Network - August 30th, 2017
- Quantum Computing Is Coming at Us Fast, So Here's Everything You Need to Know - ScienceAlert - August 27th, 2017
- How quantum mechanics can change computing - San Francisco ... - San Francisco Chronicle - August 25th, 2017
- Commonwealth Bank investing in Australia's first quantum computer company - Which-50 (blog) - August 25th, 2017
- How quantum mechanics can change computing - The Conversation US - August 23rd, 2017
- Introducing Australia's first quantum computing hardware company - Computerworld Australia - August 23rd, 2017
- IEEE Approves Standards Project for Quantum Computing ... - insideHPC - August 23rd, 2017
- $495.3 Million Quantum Computing Market 2017 by Revenue Source, Application, Industry, and Geography - Global ... - PR Newswire (press release) - August 18th, 2017
- Physicists Have Made Exotic Quantum States From Light - Futurism - August 16th, 2017
- Machine learning tackles quantum error correction - Phys.Org - August 15th, 2017
- Quantum Internet Is 13 Years Away. Wait, What's Quantum Internet? - WIRED - August 15th, 2017
- Blind quantum computing for everyone - Phys.org - Phys.Org - August 12th, 2017
- Quantum Computing Is Real, and D-Wave Just Open ... - WIRED - August 12th, 2017
- Quantum Computing Market Worth 495.3 Million USD by 2023 | 08 ... - Markets Insider - August 10th, 2017
- China uses a quantum satellite to transmit potentially unhackable data - CNBC - August 10th, 2017
- Physicists Take Big Step Towards Quantum Computing and ... - Universe Today - August 1st, 2017
- Why you might trust a quantum computer with secretseven over ... - Phys.Org - July 12th, 2017
- Quantum-computer node uses two different ion species - physicsworld.com - July 10th, 2017
- Quantum Computers vs Bitcoin How Worried Should We Be? - The Merkle - July 10th, 2017

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