Quantum Supremacy: The Death of Blockchain?

In the coming years, the blockchain will play a greater role in our lives. Yet that role could be threatened if things are not put in order first.

James Dargan
The Dark Side
3 min readApr 7, 2020


Photo by Lina White on Unsplash

53 Qubits

Late last year in October, Google announced that it had achieved ‘Quantum Supremacy’ on its 53-qubit quantum computer. The phrase means, in layman’s terms, that a quantum device can solve any given problem that a classical computer/supercomputer can’t. After the announcement, there was both celebration and derision from all corners. In a blog post On Quantum Supremacy posted shortly after the event, IBM said its supercomputer Summit could do the ‘task’ in two and a half days, and not the 10,000 years claimed by Google.

Whatever the reality, it’s remarkable that quantum computing (QC) has come this far in such a short time.

Let’s give them a round of applause and stop the catfighting.

Esoteric mathematical calculations aside, the achievement is, whether true or not (true we hope), something can bring the technology into a level of efficacy that can best serve humanity.

It is too early to say how QC will do in designing suitable drugs to fight future COVID-19-like pandemics because currently, the level of technology is just not there. They are but theoretical toys, playthings. In a few decades, perhaps, they could be seen as the miracle cure.

For now, though, quantum computers can play an important role in the security of blockchain architecture. The reason being they are the greatest threat to breaking it, which is not a good thing for businesses that rely on the blockchain for commercial purposes.

Friendly Enemy

Bitcoin and other cryptocurrencies rely heavily on the blockchain to operate. If the blockchain gets compromised, then all hell breaks loose. We should see QC as a ‘friendly enemy,’ a wolf that can eat us alive yet knowing it is there and is a deadly predator can keep us on our toes.

And this is a good thing.

Adam Koltun, a lead business strategist at the Quantum Resistant Ledger (QRL) Foundation, puts it this way:

‘A decade ago people said it would take 50 years to get where we are now with quantum computing. Five years ago, they said it would take 25 years to get where we are now. So quantum computing has this nasty habit of exceeding people’s expectations. The blockchain industry does need to grapple with this and be wary.’

This, of course, could be doom-mongering on a grand scale. Or it could just be careful words. Words we should consider.

Crackers and Enciphers

In theory, a workable quantum computer could breach the security of the blockchain because digital signatures based on elliptic curve cryptography (ECC) secure transactions on it. This architecture, sadly, is not quantum-safe. This could mean, again in theory, breaking the private keys of users and then faking the signatures of the said transactions. This could lead to the collapse of Bitcoin and cryptocurrencies, as the sole purpose of the operation is based on trust and anonymity.

Photo by Joshua Hoehne on Unsplash

Another expert, Charles Hayter of CryptoCompare, believes:

‘Cryptocurrencies can be updated with quantum-resistant tech. This is just a continuation of the age-old arms race between crackers and enciphers.’

What is needed, then, is quantum-resistant, public-key cryptographic algorithms, ones that are fit for purpose, in line with the rapid pace in which QC is improving regarding qubit power and deliverable functionality. That way, assurances can be made that the blockchain is safe and able to operate without hindrances threatening its very existence.



James Dargan
The Dark Side

Author & futurist writing about quantum computers, AI, crypto/blockchain. Journalist @ thequantumdaily.com Read my fiction on Amazon or jamesdargan.com