An overview of the threats posed by quantum computing, and how we’re tackling them.
4 min read · Oct 22, 2023
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Bitcoin, NFTs, cryptocurrencies, DeFi. I’m sure you’ve heard of at least one of these. They’re all built upon a key technology; blockchain.
Blockchain is a decentralized digital ledger that records data in a way that ensures transparency, security, and trust in a tamper-proof manner.
One of the key features of blockchain is security. Automated consensus mechanisms make the blockchains extremely secure to attacks. This is really important, especially when dealing with cryptocurrencies.
The decentralization and security that comes with blockchain technology offers a new way to operate across multiple sectors. From supply chains to finance, it makes things more transparent, and trustable.
But here’s the problem. Quantum computing can potentially crush it all.
Let me explain.
Quantum computing is a fast-growing technology that uses the laws of quantum mechanics to overcome the limitations of normal computers.
The Power of Quantum Computing
Here’s an example to demonstrate just how powerful this already is- and just how powerful it’s set to become.
In 2019, Google announced that its quantum computer solved a particular problem in 200 seconds. One that would’ve taken a classical one about 10,000 years. Here’s what that looks like in numbers:
1/15,768,000,000 — That means the quantum computer was 15.77 billion times faster. It was also that much more powerful.
Mind-blowing, right?
But that only shows what it was. Quantum computers are a rapidly growing technology. They’re only going to get more powerful, and more versatile.
Public Key Cryptography Vulnerabilities
Public key cryptography is the foundation of blockchain’s security. However, it faces a growing threat from quantum computing.
Public key cryptography is a way of encrypting and decrypting data using private and public keys to protect it from unwanted unauthorized access.
It uses cryptographic methods such as RSA and ECDSA which rely on the difficulty of factoring large numbers. However, with the emergence of quantum algorithms like Shor’s, this can be done- quite efficiently
Quantum Attacks on Blockchain
Quantum attacks on blockchains are not just theoretical, projected events. They’re real, and they’re coming.
In fact, according to a study, cryptocurrencies such as Bitcoin and Litecoin are currently vulnerable to quantum attacks. A Deloitte study found that over 65% of all Ether is currently vulnerable to a quantum attack.
We’re talking about the two largest cryptocurrencies- Bitcoin and ethereum. Together, they have a market capitalization worth trillions of dollars. Any disruption and loss of trust would be result in significant consequences.
Attackers armed with quantum computing can exploit vulnerabilities to steal wealth, perform the 51% attack and much more, ultimately resulting in the loss of trust in blockchain networks.
In a more lighthearted tone, quantum computing is currently not at a stage to perform such threatening algorithms just yet.
IBM had a 65-qubit quantum computer as of late 2020, whereas it’s estimated that 1500 qubits are required to crack the code to hack Bitcoin private keys. Current quantum computers, though have impractically high error rates and can only operate at temperatures close to absolute zero.
So when will they be able to attack?
Estimates range from several years to a few decades. The most optimistic ones say that could be capable of breaking the signature scheme in less than 10 min by 2028. Although most claim it’ll be 10+ years away.
But that shouldn’t stop us from working on preventative measures.
Post-Quantum Cryptography
So why can’t we just make these algorithms more complicated?
That’s exactly what we’re doing.
Post quantum cryptography is this new generation of cryptographic methods that are specifically designed to resist potential quantum attacks.
For example, lattice-based encryption is built on complex mathematical frameworks known as lattices. These lattices have a strong foundation that quantum algorithms find difficult to breach. Multivariate polynomial cryptography employs complex mathematical equations.
These cutting-edge cryptographic approaches could be used to strengthen blockchain’s security against quantum attacks.
Challenges in application and transition
Transitioning to a whole new method of encryption isn’t easy though.
Post quantum algorithms generally use longer key sizes and require more processing power than traditional cryptographic algorithms. This can disrupt some apps or perhaps affect them in different ways. So yes- a lot of testing and adjusting is definitely required.
A lot of compatibility issues may arise as well. Transitioning to post quantum cryptography isn’t just about the technicality aspect though, changing these systems requires a level of coordination, effort and planning.
After reading through this article, you’d probably be thinking-
How would complicating encryption secure blockchains? Won’t quantum computers eventually be able to crack those too?
To be honest, I agree. Although researchers are looking for ways to change blockchains structurally to withstand quantum computing attacks, until they find one, it’s essentially a race.
I imagine it as a high-stakes race — a sprint where blockchain developers are urgently working to make their systems quantum-resistant, to stay ahead of the evolving quantum computers.
And it’s not just blockchains. Many web softwares integral to society currently use the same algorithms used by blockchains.
As this race continues, I see it as the evolution of technology. It’s the constant drive to innovate, push boundaries, and emerge even more potent when facing unanticipated threats.
What do you think?
