Research keeps lowering the qubit count needed to break Bitcoin's encryption

[QuantumOracle45]

A growing body of research has repeatedly lowered estimates for how many qubits a quantum computer would actually need to break the elliptic curve cryptography protecting Bitcoin and Ethereum wallets. A Google Quantum AI whitepaper estimated an attack on Bitcoin's secp256k1 cryptography could require as few as 1,200 logical qubits and roughly 70 to 90 million Toffoli gates, translating to fewer than 500,000 physical qubits on a superconducting quantum computer, an estimate roughly 20 times lower than prior projections that ran into the millions

Blockchain keys are especially exposed compared to other systems using similar cryptography, since keys used in many blockchains run almost an order of magnitude smaller than RSA keys at comparable security levels, meaning a less powerful quantum computer could still break them. Estimated resource requirements for Shor's algorithm, the quantum method used to break this kind of public key encryption, have fallen roughly five orders of magnitude over two decades, from around 1 billion physical qubits in 2012 down to the tens of thousands some newer estimates now suggest

Researchers stress this doesn't mean quantum computers can break Bitcoin today, current hardware remains two to three orders of magnitude short of these thresholds, and Bitcoin's mining process specifically remains safe since Grover's algorithm only offers a limited square root speedup against the hashing function involved, an advantage quantum error correction largely eats up anyway. The genuine risk applies specifically to wallets whose public keys have already been revealed on chain through past transactions. Curious what people think this steadily shrinking threshold means for how urgently the crypto industry should actually be moving toward post-quantum signature schemes

Quantum Computers Need Fewer Resources To Break Blockchain Keysquantumzeitgeist.com