The key cryptographic protocols used to secure the internet and financial transactions of today are all susceptible to attack by the development of a sufficiently large quantum computer. One particular area at risk is cryptocurrencies, a market currently worth over 100 billion USD. We investigate the risk posed to Bitcoin, and other cryptocurrencies, by attacks using quantum computers. We find that the proof-of-work used by Bitcoin is relatively resistant to substantial speedup by quantum computers in the next 10 years, mainly because specialized ASIC miners are extremely fast compared to the estimated clock speed of near-term quantum computers. On the other hand, the elliptic curve signature scheme used by Bitcoin is much more at risk, and could be completely broken by a quantum computer as early as 2027, by the most optimistic estimates. We analyze an alternative proof-of-work called Momentum, based on finding collisions in a hash function, that is even more resistant to speedup by a quantum computer. We also review the available post-quantum signature schemes to see which one would best meet the security and efficiency requirements of blockchain applications.
The key cryptographic protocols used to secure the internet and financial transactions of today are all susceptible to attack by the development of a sufficiently large quantum computer. One particular area at risk is cryptocurrencies, a market currently worth over 100 billion USD. We investigate the risk posed to Bitcoin, and other cryptocurrencies, by attacks using quantum computers. We find that the proof-of-work used by Bitcoin is relatively resistant to substantial speedup by quantum computers in the next 10 years, mainly because specialized ASIC miners are extremely fast compared to the estimated clock speed of near-term quantum computers. On the other hand, the elliptic curve signature scheme used by Bitcoin is much more at risk, and could be completely broken by a quantum computer as early as 2027, by the most optimistic estimates. We analyze an alternative proof-of-work called Momentum, based on finding collisions in a hash function, that is even more resistant to speedup by a quantum computer. We also review the available post-quantum signature schemes to see which one would best meet the security and efficiency requirements of blockchain applications.
Cryptocurrency are decentralized digital money systems built on blockchain technology. The transactions are secured in these system using digital signatures based on public-key cryptography. Public-key cryptographic algorithms used for digital signatures, such as ECDSA, are vulnerable to quantum attacks. With over 2 trillion dollars market capitalization, the cryptocurrency industry will be at high risk in the Quantum Era. This paper evaluates the security of today's cryptocurrency blockchains under quantum attacks. It also reviews some of the proposed solutions to protect blockchains in the Quantum Era. Moreover, it presents a number of post-quantum digital signature schemes used to build quantum-safe blockchains. The result of this study shows that only a small portion of cryptocurrency can resist quantum attacks, while most of the cryptocurrencies used today are vulnerable to quantum attacks, with more than 99.8% of the total cryptocurrency market cap remains at risk. Useful recommendations are provided as a result of this study.
Quantum computation represents a threat to many cryptographic protocols in operation today. It has been estimated that by 2035, there will exist a quantum computer capable of breaking the vital cryptographic scheme RSA2048. Blockchain technologies rely on cryptographic protocols for many of their essential sub-routines. Some of these protocols, but not all, are open to quantum attacks. Here we analyze the major blockchain-based cryptocurrencies deployed today—including Bitcoin, Ethereum, Litecoin and ZCash, and determine their risk exposure to quantum attacks. We finish with a comparative analysis of the studied cryptocurrencies and their underlying blockchain technologies and their relative levels of vulnerability to quantum attacks.
Quantum computing's development poses a significant threat to the cryptographic security of current blockchain technologies, potentially undermining the integrity of digital transactions. Quantum computers can break the complex mathematical problems that algorithms like RSA and ECC rely on, which could lead to vulnerabilities such as double-spending and fraud. To address these risks, the blockchain community is exploring quantum-resistant protocols that employ post-quantum cryptographic algorithms, which are designed to withstand quantum computing attacks. Quantum-secure blockchain protocols integrate quantum key distribution (QKD) and post-quantum cryptography (PQC) to enhance security. QKD uses quantum mechanics principles to secure communication channels, ensuring that any attempt to intercept the key introduces detectable anomalies. PQC involves algorithms like lattice-based, hash-based, or multivariate polynomial-based algorithms that are believed to be secure against quantum attacks. These protocols aim to maintain the confidentiality, integrity, and security of data transmitted over the blockchain, ensuring the longevity and reliability of blockchain systems in the face of evolving computational advancements. A quantum-secure blockchain scheme (QSB) utilizes a consensus mechanism, QPoA, and IQS. The QPoA is leveraged for block generation while the IQS is deployed in transaction verification1. Furthermore, the integration of quantum computing with blockchain can address current limitations, such as slow transaction speeds and lack of scalability, by optimizing calculations and enabling smarter, more sophisticated smart contracts. The development and implementation of quantum-resistant blockchains are essential for future-proofing digital transactions and maintaining trust in decentralized systems
Quantum computers pose a fundamental threat to blockchain systems that rely on elliptic-curve cryptography. This work reviews the quantum vulnerabilities and associated economic risks of major blockchain platforms, with a focus on Bitcoin, Ethereum, and Solana. We distinguish between at-rest, on-spend, and on-setup attacks and identify the blockchain components most exposed to quantum adversaries. We further review practical migration strategies toward post-quantum security, including NIST-standardized digital signatures and emerging solutions for Solana, Algorand, and Ethereum.
This paper examines the growing threat that quantum computing presents to blockchain security. Core blockchain cryptographic frameworks, specifically the Elliptic Curve Digital Signature Algorithm and the Secure Hash Algorithm 256, are vulnerable to quantum algorithms. Both the Shor algorithm and the Grover algorithm are capable of breaking the Elliptic Curve Digital Signature Algorithm, enabling attackers to calculate private keys from public keys, while the Grover algorithm can also compromise hash-based systems that depend on brute-force methods, such as Proof-of-Work. On-chain analysis indicates that billions of dollars’ worth of crypto-assets are held in addresses susceptible to these quantum attacks. A proposed countermeasure is migration to Post-Quantum Cryptography, which incorporates quantum-resistant algorithms, such as CRYSTALS-Dilithium and Falcon. However, this migration introduces a trilemma among network security, decentralization, and performance. Post-Quantum Cryptography algorithms significantly increase transaction sizes and computational costs, which pose economic and technical challenges for large blockchain networks. The paper further discusses how the timeline for quantum advancements will be shaped by geopolitical competition, and how the catch-the-crop, decrypt-later strategy puts current data at risk from future quantum decryption. It emphasizes that active migration to Post-Quantum Cryptography is urgent, calling on stakeholders to prioritize system audits, transition to cryptographically flexible infrastructures, promote research into quantum-resistant solutions, and establish governance frameworks that enable prompt and decentralized upgrades.
Quantum computing poses a real, broad-based, but bounded and substantially mitigable threat to Bitcoin and Ethereum. We separate the two quantum algorithms that public discussion routinely conflates: Shor's algorithm breaks the elliptic-curve signatures (ECDSA over secp256k1, BLS over BLS12-381) that authorize spending, whereas Grover's algorithm does not meaningfully threaten proof-of-work mining, which is protected by a merely quadratic speedup, fault-tolerant per-operation costs, a square-root parallelization wall, and difficulty adjustment. Folding hardware scaling, the falling resource requirement, a fault-tolerance readiness lag, and expert surveys into a single Monte-Carlo forecast yields a wide, bimodal arrival distribution for a cryptographically relevant quantum computer: about a one-in-six chance by 2035, near 30% by 2040, and about 60% by 2050. Exposure is concentrated and mostly migratable: of Bitcoin's roughly six million quantum-exposed coins only about 2.3 million are irreducibly at risk, while 50 to 65% of Ether sits at key-revealed accounts that can adopt post-quantum signatures. A timely migration beats even an optimistic 2035 machine, so the binding constraint is governance, not technology. A survey of the top twenty cryptocurrencies finds none fully post-quantum. Reproducible models accompany every quantitative claim.