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I'll search for current information about quantum computing's potential impact on Bitcoin's cryptographic security to give you an accurate, up-to-date answer. Quantum computers represent a theoretical long-term threat to Bitcoin's cryptography, but they cannot crack Bitcoin's encryption with current technology. The threat primarily centers on two cryptographic systems that secure Bitcoin: the Elliptic Curve Digital Signature Algorithm (ECDSA) for wallet security and SHA-256 for mining and transaction integrity.

Current Quantum Computing Capabilities

Current quantum computers, including Google's advanced Willow chip, operate with around 100 qubits and are nowhere near the scale required to break Bitcoin's encryption 1. To crack ECDSA within an hour, a quantum computer would need approximately 317 million physical qubits - orders of magnitude beyond today's capabilities 3. Even extending the timeline to five years would still require around 6,000 qubits.

Specific Vulnerabilities

ECDSA Vulnerability: Quantum computers using Shor's algorithm could theoretically break the ECDSA signatures that protect Bitcoin wallets. However, this threat is primarily limited to Bitcoin addresses that have exposed their public keys on the blockchain - approximately 25% of all Bitcoin, including potentially 1 million coins believed to belong to Satoshi Nakamoto 4.

SHA-256 Resistance: Bitcoin's SHA-256 hashing algorithm is more resistant to quantum attacks. While Grover's algorithm could theoretically reduce the computational effort from 2^{256 to 2}128 operations, this still represents an astronomically large number of computations that would be impractical even for advanced quantum computers 3.

Timeline and Expert Consensus

Most cryptography experts estimate that quantum computers capable of threatening Bitcoin are at least a decade away, with estimates ranging from the 2030s to the 2040s 1. IBM's roadmap suggests reaching only a few thousand qubits by 2033, still far short of the millions needed for practical attacks on Bitcoin's cryptography.

Proposed Solutions

The Bitcoin community is proactively addressing this potential threat through a new Bitcoin Improvement Proposal (BIP) that outlines a three-phase transition to post-quantum cryptography 6:

Phase 1: Block new transactions to quantum-vulnerable addresses and require use of post-quantum address types (P2QRH)

Phase 2: Freeze funds that haven't been moved to secure addresses after two years

Phase 3: Allow recovery of frozen assets using seed phrases (still under development)

Bottom Line

While quantum computers pose a theoretical future risk to Bitcoin, the threat is not imminent with current technology. The Bitcoin community has time to implement quantum-resistant solutions, and active development is already underway to ensure the network's long-term security against this potential threat.