ECDSA Quantum Computing and SHA-256 For Bitcoin Security
ECDSA Quantum Computing
Bitcoin Vulnerability and Google Quantum Advances Recent reports of Google's quantum factoring accomplishments have raised Bitcoin security concerns. Google researchers refined Shor's method and improved quantum decoherence error correction to reduce the number of qubits needed to break RSA-2048 from 20 million to one million. Despite this progress, the greatest quantum processor has just 1021 qubits, and more qubits make quantum coherence harder. In spite of claims of greater qubit counts, factoring tiny numbers like 35 has not improved.
Bitcoin's major security methods are SHA-256 and ECDSA. Shor's technique solves the discrete logarithm problem tenfold faster than classical computers, which could allow a quantum computer to extract a Bitcoin private key from a public key.
Google's recent discovery doesn't affect Bitcoin's “secp256k1” elliptic curve, although ECDSA is reportedly easier to breach than RSA. AI may help Shor's algorithm avoid ECDSA, according to Pauli Group founder. The Bitcoin curve's “secp32k1” may be cracked by 2027 and “secp256k1” by 2029, according to quantum computer pioneer IonQ. These forecasts should be taken “with a big grain of salt.”
A 2022 Deloitte analysis found that quantum attacks might affect 4 million Bitcoin, 25% of the supply. Older P2PK and P2PKH addresses that reveal public keys may be targeted by these attacks. Dormant wallets like Satoshi Nakamoto's are susceptible. Along with digital signatures, Grover's method may exploit Bitcoin's SHA-256 hash function, which might benefit quantum miners and lead to centralised mining power or a 51% attack.
Temporal and Mitigation Methods Due to hardware stability and error correction issues, experts expect quantum computers that could threaten encryption standards to appear in the 2030s, perhaps ten or more years away. The 13–300 million qubits needed to practically attack ECDSA are beyond contemporary quantum computers. However, enemies may capture encrypted data to decrypt it later.
The Bitcoin community is developing solutions:
Since 2016, NIST has standardised quantum-resistant algorithms for post-quantum cryptography (PQC). CRYSTALS-Dilithium, SPHINCS+, and FALCON, three digital signature competitors, may replace ECDSA. Quantum computers struggle with mathematical issues, which underlie them.
Hunter Beast proposed BIP-360, a “pragmatic first step” through a soft fork that would include additional UTXO types and addresses starting with “bc1r.” It advises adding post-quantum and ECDSA signatures to transactions so an ECDSA backup can be utilised if a post-quantum approach fails. Hunter Beast supports FALCON due to signature aggregation.
PQC Integration Challenges: PQC implementation isn't free. Larger signatures and keys will slow on-chain transaction throughput and signature creation and verification. FALCON signatures are 20 times larger than Schnorr and 13 times larger than ECDSA, whereas SPHINCS+ signatures can be 40 times larger, potentially resulting in 40 times fewer transactions per block.
The conceptual proposal BIP “Quantum-Resistant Address Migration Protocol” (QRAMP) by Agustin Cruz is also being explored. It would require a hard fork that erases bitcoins not migrated to post-quantum addresses. Like the Taproot upgrade, transitions will likely be voluntary migrations and soft forks. Satoshi Nakamoto's inactive address may cause heated debates.
Bitcoin developers may replace SHA-256 with a quantum-resistant hash algorithm to prevent a quantum-driven mining oligopoly. Theory suggests it's conceivable.
Bitcoin's Function and Social Impact Quantum risk affects banking, payments, communications, healthcare, and government networks that use RSA and ECC, not only Bitcoin. A “Q-Day” breach could damage trust and global finance. The 2023 EY Quantum Approach to Cybersecurity research suggests that quantum computers could crack current cryptography in five to thirty years by 50% to 70%. The US federal government mandates PQC by 2035.
Bitcoin's decentralised governance and $2 trillion market value motivate developers to construct quantum-resistant solutions that could set a standard for other industries. Texas A&M scientist Korok Ray says Bitcoin's open-source design and active developer community make it unique in its ability to react to quantum threats. BlackRock has listed quantum computing as a long-term risk in Bitcoin ETF filings.