Will Quantum Computing Kill Bitcoin? | Scott Aaronson & Justin Drake
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What are the potential impacts of quantum computing on Bitcoin and Ethereum?
Quantum computing could break elliptic curve cryptography (ECDSA) used in Bitcoin and Ethereum, allowing attackers to derive private keys from public keys and steal funds. Additionally, quantum computers could disrupt Bitcoin's proof-of-work mining by significantly accelerating the search for valid nonces, potentially centralizing mining power.
What is the current state of quantum computing in terms of breaking cryptographic codes?
Quantum computing is still in its early stages, with the first logical qubit demonstrated by Google's Willow chip. Breaking cryptographic codes like RSA or ECDSA would require millions of physical qubits and thousands of logical qubits, which is currently beyond our capabilities. However, progress is accelerating, and some experts estimate it could take a decade or more to achieve this.
How does quantum computing differ from classical computing in terms of problem-solving?
Quantum computers exploit quantum mechanics to solve specific problems exponentially faster than classical computers. They use superposition and interference to perform computations, but they are not universally faster. Quantum computers excel at tasks like factoring large numbers (Shor's algorithm) and searching large datasets (Grover's algorithm), but they offer little advantage for many everyday computing tasks.
What are the risks to Bitcoin if quantum computers become capable of breaking ECDSA?
If quantum computers can break ECDSA, attackers could steal Bitcoin from addresses where public keys are exposed. This includes Satoshi's 1 million Bitcoin and other stagnant or lost coins. Bitcoin would need to hard fork to implement post-quantum cryptography, but this would require social consensus and could disrupt the network's immutability and property rights.
How is Ethereum addressing the threat of quantum computing?
Ethereum is exploring upgrades to its cryptography, including post-quantum secure signature schemes and consensus mechanisms. Account abstraction allows users to adopt quantum-resistant cryptography without requiring a hard fork. Ethereum also has plans to upgrade its BLS signatures and implement quantum-resistant data structures like binary Merkle trees.
What is quantum money, and how does it differ from traditional cryptocurrencies?
Quantum money uses the no-cloning theorem of quantum mechanics to create physically unclonable cash. Unlike traditional cryptocurrencies, quantum money does not rely on proof-of-work or consensus mechanisms. It allows for secure, trustless transactions without the need for a blockchain, but it requires advanced quantum technology to preserve quantum states over time.
What is the timeline for quantum computing to become a threat to cryptography?
Experts estimate it could take 10 to 30 years for quantum computers to become capable of breaking current cryptographic standards. However, the timeline depends on advancements in quantum error correction, qubit scalability, and investment in quantum research. Governments and private companies are already investing billions in quantum technology, accelerating progress.
How could quantum computing disrupt Bitcoin's proof-of-work mining?
Quantum computers could use Grover's algorithm to accelerate the search for valid nonces in Bitcoin mining. This could give early adopters of quantum mining hardware a significant advantage, potentially centralizing mining power. Over time, as quantum mining becomes more widespread, the proof-of-work difficulty would adjust, but the transition could be destabilizing.
What are the potential consequences of quantum computing for Satoshi's Bitcoin?
Satoshi's 1 million Bitcoin could become a target for quantum attackers if the private keys can be derived from public keys. This could lead to a massive transfer of wealth to whoever develops the first capable quantum computer. The Bitcoin community may need to hard fork to protect these coins, but this would require significant social consensus and could challenge Bitcoin's principles of immutability.
What are the trade-offs of implementing post-quantum cryptography in Ethereum?
Post-quantum cryptography often results in larger signature sizes, increasing transaction costs and bandwidth requirements. Ethereum is exploring optimizations like signature aggregation and new peer-to-peer network architectures to mitigate these trade-offs. Despite the challenges, the transition is necessary to ensure long-term security against quantum threats.
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