Quantum Attacks on Bitcoin, and How to Protect Against Them (original) (raw)

Assessment of Quantum Threat To Bitcoin and Derived Cryptocurrencies

IACR Cryptol. ePrint Arch., 2021

All cryptocurrencies are not the same. Today, they share a common quantum vulnerability through use of non-quantum safe Elliptic Curve Digital Signature Algorithm (ECDSA) digital signatures yet they have very different risks of quantum attack. The risk of attack for a cryptocurrency depends on a number of identified factors such as the block interval time, the vulnerability to an attack that delays the time for an unprocessed transaction to be completed and the behaviour of a cryptocurrency user to increase the cost of a quantum computer attack. Shor’s algorithm can be used to break ECDSA signatures with a quantum computer. This research addresses the two questions: When will a quantum computer be powerful enough to execute Shor’s algorithm? How fast would a quantum computer need to be to break a specific cryptocurrency? In this paper we observe that by benchmarking the speed of circuits and the time for quantum addition on quantum computers we can determine when there is a potentia...

Quantum computers put blockchain security at risk

Nature, 2018

rebooted brain research p.474 MUSIC Celebrating the female pioneers of electronica p.470 SPACE Rock legend Brian May retells the race to the Moon-in 3D p.469 CONSERVATION The people and places that invented the word 'environment' p.468 Quantum computers put blockchain security at risk Bitcoin and other cryptocurrencies will founder unless they integrate quantum technologies, warn Aleksey K. Fedorov, Evgeniy O. Kiktenko and Alexander I. Lvovsky. B y 2025, up to 10% of global gross domestic product is likely to be stored on blockchains 1. A blockchain is a digital tool that uses cryptography techniques to protect information from unauthorized changes. It lies at the root of the Bitcoin cryptocurrency 2. Blockchain-related products are used everywhere from finance and manufacturing to health care, in a market worth more than US$150 billion. When information is money, data security, transparency and accountability are crucial. Quantum cryptography equipment, which uses the principle of entanglement to encode data that only the sender and receiver can access.

Quantum-Resistance in Blockchain Networks

2021

This paper describes the work carried out by the Inter-American Development Bank, the IDB Lab, LACChain, Cambridge Quantum Computing (CQC), and Tecnológico de Monterrey to identify and eliminate quantum threats in blockchain networks. The advent of quantum computing threatens internet protocols and blockchain networks because they utilize non-quantum resistant cryptographic algorithms. When quantum computers become robust enough to run Shor's algorithm on a large scale, the most used asymmetric algorithms, utilized for digital signatures and message encryption, such as RSA, (EC)DSA, and (EC)DH, will be no longer secure. Quantum computers will be able to break them within a short period of time. Similarly, Grover's algorithm concedes a quadratic advantage for mining blocks in certain consensus protocols such as proof of work. Today, there are hundreds of billions of dollars denominated in cryptocurrencies that rely on blockchain ledgers as well as the thousands of blockchain-...

The Bitcoin Backbone Protocol Against Quantum Adversaries

IACR Cryptol. ePrint Arch., 2019

Bitcoin and its underlying blockchain protocol have received recently significant attention in the context of building distributed systems as well as from the perspective of the foundations of the consensus problem. At the same time, the rapid development of quantum technologies brings the possibility of quantum computing devices from a theoretical concept to an emerging technology. Motivated by this, in this work we revisit the formal security of the core of the Bitcoin protocol, called the Bitcoin backbone, in the presence of an adversary that has access to a scalable quantum computer. We prove that the protocol’s essential properties stand in the post-quantum setting assuming a general quantum adversary with suitably bounded number of queries in the Quantum Random Oracle (QRO) model. In order to achieve this, we investigate and bound the quantum complexity of a Chain-of-Proofs-of-Work search problem which is at the core of the blockchain protocol. Our results imply that security ...

Navigating the Quantum Computing Threat Landscape for Blockchains: A Comprehensive Survey

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. We begin by surveying the existing literature on blockchains and quantum computing, providing insights into the current state of research. We then present an overview of blockchain, highlighting its key components and functionalities. We delve into the preliminaries and key definitions of quantum computing, establishing a foundation for understanding the implications on blockchain security. The application of blockchains in cybersecurity is explored, considering their strengths ...

Protecting Quantum Procrastinators with Signature Lifting: A Case Study in Cryptocurrencies

arXiv (Cornell University), 2023

Current solutions to quantum vulnerabilities of widely used cryptographic schemes involve migrating users to post-quantum schemes before quantum attacks become feasible. This work deals with protecting quantum procrastinators: users that failed to migrate to post-quantum cryptography in time. To address this problem in the context of digital signatures, we introduce a technique called signature lifting, that allows us to lift a deployed pre-quantum signature scheme satisfying a certain property to a post-quantum signature scheme that uses the same keys. Informally, the said property is that a post-quantum one-way function is used "somewhere along the way" to derive the public-key from the secret-key. Our constructions of signature lifting relies heavily on the post-quantum digital signature scheme Picnic (Chase et al., CCS'17). Our main case-study is cryptocurrencies, where this property holds in two scenarios: when the publickey is generated via a key-derivation function or when the public-key hash is posted instead of the public-key itself. We propose a modification, based on signature lifting, that can be applied in many cryptocurrencies for securely spending pre-quantum coins in presence of quantum adversaries. Our construction improves upon existing constructions in two major ways: it is not limited to pre-quantum coins whose ECDSA public-key has been kept secret (and in particular, it handles all coins that are stored in addresses generated by HD wallets), and it does not require access to post-quantum coins or using side payments to pay for posting the transaction.

Quantum solutions to possible challenges of Blockchain technology

ArXiv, 2021

Technological advancements of Blockchain and other Distributed Ledger Techniques (DLTs) promise to provide significant advantages to applications seeking transparency, redundancy, and accountability. Actual adoption of these emerging technologies requires incorporating cost-effective, fast, QoS-enabled, secure, and scalable design. With the recent advent of quantum computing, the security of current blockchain cryptosystems can be compromised to a greater extent. Quantum algorithms like Shor’s large integer factorization algorithm and Grover’s unstructured database search algorithm can provide exponential and quadratic speedup, respectively, in contrast to their classical counterpart. This can put threats on both public-key cryptosystems and hash functions, which necessarily demands to migrate from classical cryptography to quantum-secure cryptography. Moreover, the computational latency of blockchain platforms causes slow transaction speed, so quantum computing principles might pro...

Bitcoin Security with Post Quantum Cryptography

Lecture Notes in Computer Science, 2019

In a future quantum world with a large quantum computer, the security of the digital signatures used for Bitcoin transactions will be broken by Shor's algorithm. Bitcoin has to switch to post-quantum cryptography. In this paper, we show that the post quantum signatures based on LWE and ring LWE are the most promising to use in the presence of large quantum computers running Shor's algorithm.

Post-Quantum Security of the Bitcoin Backbone and Quantum Multi-Solution Bernoulli Search

ArXiv, 2020

Bitcoin and its underlying blockchain protocol have recently received significant attention in the context of building distributed systems and foundations of the consensus problem. At the same time, the rapid development in quantum computing makes the threats to cryptography more and more concerning. In this work, we revisit the formal security of the core of the Bitcoin consensus protocol, called the Bitcoin backbone (Eurocrypt 2015), in the presence of quantum adversaries – i.e. adversaries equipped with quantum computers. We show that the security of the Bitcoin backbone holds under a quantum analogue of the “honest majority” assumption that we develop. The critical ingredient of proving security of the blockchain is to analyzing the quantum query complexity of a Chain-of-Proofs-of-Work search problem. This problem in turn reduces to a problem we call multi-solution Bernoulli search, for which we establish its quantum query complexity. This can be viewed as an extension of a thre...

Resistant Blockchain Cryptography to Quantum Computing Attacks

2021

Due to the need to maintain confidentiality, redundancy, and openness, the usage of Blockchain and other DLTs has dramatically advanced in recent years, and is being recommended for various applications. In blockchain, these capabilities are supplied by means of hash functions and public-key encryption. However, the rapid development of quantum computation in the near future has opened the door to the Grover and Shor algorithms. These algorithms challenge both public and hash encryption, causing blockchains to redesign and use quantum attack-tolerant cryptosystems; this produces cryptosystems which are considered post-quantum cryptosystems, which are quantum-resistant. This paper reviews current scientists on quantum blockchain for such purposes. In addition, the major challenges are studied with the most important post-quantum blockchain systems. In addition, the most promising post quantum signature encryption and digital blockchain signature schemes are detailed in terms of the f...