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 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 computers pose a significant threat to blockchain technology’s security, which heavily relies on public-key cryptography and hash functions. The cryptographic algorithms used in blockchains, based on large odd prime numbers and discrete logarithms, can be easily compromised by quantum computing algorithms like Shor’s algorithm and its future qubit variations. This survey paper comprehensively examines the impact of quantum computers on blockchain security and explores potential mitigation strategies. The survey focuses on the quantum security of blockchain’s fundamental building blocks, including digital signatures, hash functions, consensus algorithms, and smart contracts. We analyze the vulnerabilities introduced by quantum computers and discuss potential countermeasures and enhancements to ensure the integrity and confidentiality of blockchain systems. Furthermore, we investigate the quantum attack surface of blockchains, identifying potential avenues for exploiting quantum computing to strengthen existing attacks. We emphasize the need for developing quantum-resistant defenses and explore solutions for mitigating the threat of quantum computers to blockchains, including the adoption of quantum and post-quantum blockchain architectures. The paper also discusses the limitations of current efforts, such as the computational overhead of post-quantum algorithms and the practical challenges in real-world deployment, illustrated through case studies of Bitcoin and Ethereum. Future research directions include developing scalable quantum-resistant blockchain protocols, optimizing cryptographic implementations for embedded devices, and establishing standardized security frameworks to mitigate emerging quantum attacks.
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 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
With the advent of quantum computing, cryptocurrencies that rely on blockchain technology face mounting cryptographic vulnerabilities. This paper presents a comprehensive literature review evaluating how quantum algorithms—specifically Shor’s and Grover’s—could disrupt the foundational security mechanisms of cryptocurrencies. Shor’s algorithm poses a threat to public-key cryptographic schemes by enabling efficient factorization and discrete logarithm solving, thereby endangering digital signature systems. Grover’s algorithm undermines hash-based functions, increasing the feasibility of 51% attacks and hash collisions. By examining the internal mechanisms of major cryptocurrencies such as Bitcoin, Ethereum, Litecoin, Monero, and Zcash, this review identifies specific vulnerabilities in transaction and consensus processes. It further analyses the current hardware limitations of quantum systems and estimates when such attacks could become feasible. In anticipation, it investigates countermeasures including Post-Quantum Cryptography (PQC), Quantum Key Distribution (QKD), and protocol-level modifications such as memory-intensive proof-of-work algorithms and multi-signature schemes. The discussion integrates recent advancements in quantum error correction, hardware scalability, and NIST-standardized cryptographic algorithms. This review concludes that while quantum computers are not yet advanced enough to pose an immediate threat, proactive integration of quantum-resistant solutions is essential. The findings underscore the urgent need for cryptocurrencies to adopt post-quantum cryptographic standards to preserve the decentralized trust, integrity, and security that define blockchain-based digital cryptocurrencies.
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 advent of quantum computing has generated apprehensions regarding the viability and security of conventional cryptographic algorithms. These algorithms safeguard the decentralized trust built into the blockchain, which relies on decentralized cryptographic consensus, instead of a central authority. Simultaneously, quantum computing has also unveiled unprecedented possibilities, opportunities and risks in the realm of technology. The significance of this is that numerous sub-routines employed within the blockchain, such as consensus protocols, data transmission, storage, and communication, heavily depend on conventional cryptographic algorithms like Rivest-Shamir-Adleman (RSA) and Elliptic Curve Digital Signature Algorithm (ECDSA). However, these algorithms are susceptible to quantum algorithms, which have the potential to effectively compromise them once quantum computers with sufficient computational capabilities are developed. Blockchain, although primarily recognized for its association with cryptocurrencies, is essentially a decentralized and trustless distributed ledger system. Its purpose is to enable decentralized communication, coordination, and the attainment of desired objectives through consensus mechanisms. A notable illustration of this concept is a blockchain transaction. The advent of quantum computing poses a significant threat to the security of blockchain systems, as the asymmetric algorithms employed within their many components will likely become obsolete. This jeopardizes the integrity of the blockchain system, which underpins a multi-billion dollar economy reliant on its inherent transparency and safety. This paper seeks to present an overview of the various threats faced by blockchain systems, examine the potential of quantum algorithms in offering cryptographic signatures for these systems, and provide a broad perspective on how to protect blockchain systems from quantum threats by utilizing quantum algorithms for cryptographic signatures. This study enhances the comprehension of existing vulnerabilities in blockchain systems, specifically focusing on the potential risks posed by quantum computing. Additionally, it sheds light on the ongoing efforts within the industry and current research endeavors aimed at addressing these weaknesses.