Even as blockchain technology emerges as a novel innovation, digital assets—such as cryptocurrencies and non-fungible tokens (NFTs)—along with the entire decentralized applications (DApps) ecosystem driven by it, confront the challenges presented by quantum computing. Quantum computing, advancing at a swift pace, utilizes the principles of quantum mechanics to forge computers capable of resolving problems deemed too intricate for classical or binary computers.
Marketed as the forthcoming era of computing, destined to surpass supercomputers (which are classical computers exhibiting significantly superior performance compared to conventional computers), quantum computers have the potential to question existing security norms owing to their computational dominance. Their proficiency in resolving highly complex problems might also jeopardize the prevailing perception of the immutability of blockchain technology.
Quantum computing, with its potential to destabilize digital security protocols, could aid malicious entities in orchestrating attacks on cryptocurrencies and various blockchain applications, despite the technology still being in its initial developmental phases.
Consequently, comprehending what renders quantum computers immensely potent and discerning how they might jeopardize blockchain-driven applications in the future becomes imperative. As the global crypto ecosystem teeters on the verge of mainstream acceptance, developers and entrepreneurs must navigate uncharted territories concerning cryptographic algorithms and innovate to mitigate the threats emanating from quantum computing.
The Working Principles of a Quantum Computer
The principal difference between quantum computers and their classical or binary counterparts resides in their approach to utilizing states to represent numbers in complex calculations. Classical computers employ bits to encode information in binary form (0 or 1), whereas quantum computers leverage quantum bits, or “qubits,” exploiting properties like quantum superposition and entanglement to simultaneously represent multiple states.
Consider the basic example of representing a number between 0 and 255. Classical computers require eight bits to represent any number within this range. In contrast, a quantum computer can represent all 256 numbers at once using eight qubits.
This characteristic enables quantum computers to consider numerous combinations and execute intricate calculations at a speed that far surpasses the capabilities of even the most advanced supercomputers. Utilizing superconducting elements that exhibit exceedingly low resistance to electron flow when chilled to sub-zero temperatures, quantum computers inherently possess sensitivity to heat, electromagnetic waves, and even air exposure, leading to computational losses in suboptimal environments.
Hence, the forthcoming era of computing may well be nestled between the capabilities of current classical computers and the advanced quantum computers, unless significant advancements materialize in crafting quantum computers suitable for commonplace use.
IBM has engineered its Quantum System One, an integrated quantum computing system boasting a 127-qubit processor. However, with quantum computing progressing at a staggering pace, the realization of a 1,000-qubit quantum computer is not beyond reach.
IBM anticipates unveiling a 1,121-qubit quantum computer processor by 2023, which is expected to make industrial-scale applications feasible and provide a computational capacity vastly surpassing that of the world’s most potent supercomputer.
Is Cryptocurrency Susceptible to Quantum Computing Attacks?
Anticipating the emergence of pure quantum computing devices on the market, the imminent wave of computing is likely to be championed by quantum-augmented supercomputers, amalgamating classical and quantum workflows.
Such devices might possess a computational capability ranging from 50 to 1,000 qubits, particularly in light of the unveiling of the 433-qubit IBM Quantum Osprey on November 9, 2022, occurring less than a year following the debut of the 127-qubit Eagle processor.
Given the considerable might of present-day quantum computers and their restricted availability, one might easily deduce that ample time remains before quantum computers pose a tangible threat to cryptocurrency.
Despite the abundant potential presented, attaining a quantum advantage will remain elusive unless advanced techniques for error suppression are devised and computational speeds are enhanced without accompanying issues.
Even exploring the scenario where quantum computing manages to overcome the cryptography underpinning cryptocurrencies, an astronomical amount of computational power would be needed to instigate a storage attack, wherein wallet addresses with a public key are targeted to pilfer the enclosed funds. For a blockchain such as the Ethereum Network, executing such a storage attack would necessitate more than 10 million qubits of computational power.
In the case of a transit attack, wherein a malevolent actor employs vast quantum computing power to hijack control of transactions within the block time, the scale is significantly larger since it involves targeting all nodes. Nevertheless, given the imperative to conduct the attack before the addition of a new block to the blockchain network, attackers are constrained to a few minutes for Bitcoin and several seconds for Ethereum to accomplish a transit attack.
Requiring billions of qubits of quantum computing power to successfully enact such an attack, blockchain developers are afforded adequate time to conceive and implement new cryptographic signing algorithms that are impervious to quantum attacks.
Is Bitcoin at Risk of Quantum Computer Theft?
Breaking the encryption that protects Bitcoin would necessitate an immense deployment of quantum computing power, all under the coordination of a single entity orchestrating the theft.
Researchers from the University of Sussex indicate that a quantum computer, wielding 1.9 billion qubits of processing power, would be requisite to infiltrate the Bitcoin network within a span of 10 minutes. This situation implies that hackers would need to mobilize millions of quantum computers—a scenario seemingly implausible in the imminent future.
If deployed with diminished computing power, executing an attack would exponentially elongate the required time, providing ample opportunity to disable the affected nodes and rehabilitate the network. While a storage attack appears more conceivable, cryptocurrencies, including Bitcoin, will inevitably need to instigate modifications to the underlying blockchain protocol to counter such eventualities.
Although this strategy might still render Bitcoin wallets vulnerable to future attacks, such changes are ostensibly easier to implement than introducing a new cryptographic algorithm. Bitcoin currently employs the Elliptic Curve Digital Signature Algorithm (ECDSA), a cryptographic methodology featuring separate signing and verification algorithms that utilize a user’s private key, public key, and signature to assure funds can be expended solely by them.
Nevertheless, public blockchains demand a consensus among significant users to sanction any amendments to their protocols, meaning that even effecting changes to Bitcoin’s protocol may necessitate more time than anticipated. Acknowledging the imperative for quantum-resistant software and cryptographic solutions, numerous projects within the cryptocurrency realm are ardently pursuing this objective.
Bitcoin’s future, in an era where quantum computing has permeated the mainstream, will likely necessitate transitioning to a more advanced, quantum-resistant ledger system, all orchestrated by a groundbreaking cryptographic algorithm.
Does Quantum Computing Spell the End for Cryptocurrency?
Quantum computers are bound to revolutionize various sectors by aiding in molecular simulations, fostering the development of energy-efficient materials and more potent medicines, and enhancing catalysts, thereby potentially benefiting numerous manufacturing industries.
Despite the foundational motive behind quantum computers being the resolution of the globe’s most perplexing problems, these machines could be leveraged to unleash chaos on public blockchains and cryptocurrency networks by malicious entities.
Addressing the question of blockchain’s longevity in the face of quantum computing necessitates the evolution of the technology into a quantum-resistant ledger system within the coming decade. This evolution is imperative mainly because quantum computers might amass enough power to assail cryptocurrencies within the next 10–15 years.
One possible solution lies in amplifying key sizes, although the feasibility of perpetually doubling key numbers as a countermeasure against perpetually strengthening quantum computers is yet to be ascertained.
Innovative cryptographic theories, such as lattice-based cryptography—where mathematical noise is integrated into the encryption to baffle a quantum computer—and quantum-resistant algorithms, which are founded on mathematical problems, are emerging as potential paths forward.
The latter methodology is crafted in such a manner that it stymies both classical and quantum computers, thereby maintaining its relevance and security in both computational domains. Regardless of whether cryptocurrencies incorporate structured lattices or hash-based algorithms, the pivotal factor will be perpetually outpacing the capabilities of quantum computers.
Therefore, while quantum computing does not currently pose a direct threat to cryptocurrencies in their existing form, a unified effort will be requisite to usher in a suite of modifications that will safeguard decentralized governance structures against the looming peril of quantum supercomputers.
Will Quantum Computers Disrupt PoW Mining?
Numerous prevalent cryptocurrencies, Bitcoin included, depend upon proof-of-work (PoW) mining to bolster the security of their foundational blockchain protocols. The PoW approach necessitates that network participants, termed miners, engage in a competitive pursuit to be the premier solvers of intricate mathematical conundrums, thereby validating new transactions on the blockchain. Cryptocurrency—referred to as block rewards—is bestowed upon the victor of this computational contest.
In due course, a quantum computer could exponentially expedite the resolution of mining puzzles compared to contemporary mining apparatuses, enabling those possessing quantum computing capabilities to accumulate mining rewards prolifically. Moreover, it allows them to potentially dominate the transaction verification process by commandeering a predominant fraction of the network’s computational power, a scenario recognized as a 51% attack.
While some researchers posit that quantum computers may not feasibly execute a 51% attack on Bitcoin until at least 2028, emerging evidence suggests such an event may transpire earlier.
Conclusion
The intersection of quantum computing and blockchain technology unveils a novel battleground in the domain of cybersecurity and digital assets. Quantum computers, with their profound computational prowess, embody both an unprecedented ally and a potential adversary for blockchain technologies and cryptocurrencies. While they hold the potential to resolve some of the most intricate problems in various fields, their capacity to compromise currently secure cryptographic systems is undeniable.
Consequently, the survival of blockchain and cryptocurrencies in a quantum-dominant future is hinged on the proactive evolution of cryptographic algorithms and securing mechanisms that are resilient to the formidable capabilities of quantum machines. The upcoming decade demands an earnest, collective endeavor from developers, cryptographers, and industry stakeholders to innovate, adapt, and safeguard decentralized digital assets against emerging quantum threats, ensuring the sustained viability and security of cryptocurrencies and blockchain technologies in a future intertwined with quantum computing.
