Bitcoin Faces Quantum Attack That Could Break Wallet Ownership Of 6.9 Million BTC

Bitcoin’s quantum risk is not framed as a threat to the blockchain ledger or mining, but as a threat to the cryptography that protects wallet ownership.

“Clock is ticking for bitcoin to prevent quantum threat as it could drain 6”

@coindesk

CoinDesk says “Quantum computers cannot disrupt bitcoin mining or the blockchain ledger itself, but they could eventually break the cryptography that protects wallet ownership.”

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It adds that “Roughly 6.9 million bitcoin, including Satoshi Nakamoto’s early holdings and any coins spent from since 2021’s Taproot upgrade, are already exposed to future quantum attacks because their public keys are visible on-chain.”

CoinDesk explains that mining and the ledger would “survive a quantum attacker,” because “Bitcoin mining… uses a type of math called hashing that quantum computers cannot meaningfully break.”

In that same framing, what would not survive is ownership, because “Bitcoin wallets are protected by a different kind of math that turns a secret private key into a public address anyone can see.”

CoinDesk also describes the asymmetry at the heart of the risk: “Turning a secret private key into a public address takes milliseconds,” while “Going the other way, from public address back to the private key, would take a regular computer longer than the age of the universe.”

The article then points to a quantum algorithm, stating that “A quantum algorithm called Shor's collapses the gap,” and ties the urgency to the timing of bitcoin’s own block production.

A separate development described by Finbold centers on a specific, publicly demonstrated quantum attack against elliptic curve cryptography, which Finbold says “confirmed” a new quantum threat level for Bitcoin.

Finbold reports that “The Bitcoin (BTC) network now faces the largest quantum threat after a researcher cracked a 15-bit elliptic curve cryptography (ECC) key on a publicly accessible quantum computer.”

CoinDesk

It specifies that on “April 24, Project Eleven… awarded 1 BTC to independent researcher Giancarlo Lelli” after Lelli “successfully derived a private key from its public key across a search space of 32,767 possible combinations.”

Finbold adds that “Lelli used cloud-based quantum hardware available to the general public to crack the 15-bit ECC,” and it contrasts the result with an earlier demonstration, saying “The previous public demonstration of such an attack class was a 6-bit break, achieved in September 2025 by Steve Tippeconnic.”

The article then quantifies the jump in feasibility, stating that “the possibility of a quantum attack on Bitcoin surged 512-fold in 8 months.”

Finbold includes a direct quote from Project Eleven’s CEO, saying “The resource requirements for this type of attack keep dropping, and the barrier to running it in practice is dropping with them,” Alex Pruden, CEO of Project Eleven, stated.

It also frames what the ECC break does and does not mean for Bitcoin, noting that “every Bitcoin wallet uses a private key, a unique 256-bit number that is mathematically related to its public key,” and concluding that “the break of 15-bit ECC is not an immediate threat to BTC, but a notable leap in less than a year.”

Both CoinDesk and Finbold converge on the idea that public information about keys is central to the risk, but they describe it at different levels of abstraction.

“The Bitcoin (BTC) network now faces the largest quantum threat after a researcher cracked a 15-bit elliptic curve cryptography (ECC) key on a publicly accessible quantum computer”

Finbold

CoinDesk says the “at-risk pool is large,” and it quantifies that “Roughly 6.9 million bitcoin, about one-third of everything ever mined, sits in wallets whose public keys are already permanently visible onchain.”

It explains that “Most of this is early bitcoin from the network's first years, stored in an address format that published the public key by default,” and it adds that the exposure also extends to “any wallet that has ever been spent from, because spending reveals the key for whatever remains.”

CoinDesk also identifies Satoshi Nakamoto’s holdings, stating that “Bitcoin’s pseudonymous creator, Satoshi Nakamoto, holds roughly 1 million bitcoin, untouched since the network's early days, and this stack now sits in the exposed category.”

Finbold, meanwhile, ties the quantum breakthrough to the structure of wallet cryptography by stating that “every Bitcoin wallet uses a private key, a unique 256-bit number that is mathematically related to its public key.”

It emphasizes that the demonstrated break was smaller than what Bitcoin uses, saying “the break of 15-bit ECC is not an immediate threat to BTC,” even as it calls it “a notable leap in less than a year.”

Finbold also provides a valuation context, stating that “With roughly 6.9 million Bitcoin, valued at approximately $534.3 billion at press time, held in wallets whose public keys are publicly visible,” the need for post-quantum transition becomes central.

CoinDesk frames the response problem as a governance and coordination challenge, contrasting bitcoin’s lack of a unified roadmap with Ethereum’s structured post-quantum migration effort.

It says “nothing concrete has emerged from Bitcoin developers yet,” and it adds that “Bitcoin has no equivalent strategy so far.”

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In the same passage, CoinDesk contrasts bitcoin with Ethereum, stating that “Ethereum… has had a formal quantum-resistant program since 2018,” and that “The Ethereum Foundation runs four teams working on the migration full-time, with more than ten independent developer groups shipping weekly test networks.”

CoinDesk also describes Ethereum’s approach as mapped across “four upcoming network-wide changes,” and it notes that “It has even launched a dedicated website, pq.ethereum.org, to publish its progress.”

For bitcoin, CoinDesk points to proposals rather than an implemented migration, saying “One such formal proposal is BIP-360 from a group of developers and researchers,” which would “add new quantum-safe address types that holders could voluntarily migrate to.”

It also mentions a competing proposal, stating that “A competing proposal from BitMEX Research would install a detection system that” (the article cuts off at that point).

Finbold, for its part, reinforces the need for transition by stating that “Project Eleven highlighted the need for blockchains to transition to post-quantum encryption.”

The sources also tie the quantum threat to specific operational timelines and to what happens if attackers can decode keys quickly enough.

“Clock is ticking for bitcoin to prevent quantum threat as it could drain 6”

CoinDesk

CoinDesk says Google’s paper this month showed the attack could be run “with far fewer resources than anyone previously estimated,” and it emphasizes that the window “races against bitcoin's own block times.”

CoinDesk

Finbold provides a more explicit schedule, stating that “Google predicted that a capable quantum computer could intercept a Bitcoin transaction by decoding its private keys from the public key in 9 minutes, before the 10-minute confirmation time, by 2029.”

It also repeats the earlier milestone that “Google researchers previously estimated that a strong enough quantum computer could break the Elliptic Curve Discrete Logarithm Problem (ECDLP) by 2029.”

In response to the confirmed ECC break, Finbold reports that “Project Eleven is developing its next challenge, focusing on the intersection of top-tier artificial intelligence (AI) models and quantum cryptanalysis.”

CoinDesk, meanwhile, frames the urgency as a race between the exposed key pool and the maturation of quantum hardware, saying the response question is “whether a network built to resist coordinated change can coordinate the biggest security upgrade in its history before the hardware catches up.”

Even so, CoinDesk’s description of exposure and ownership risk remains central, because it concludes that “What would not survive is ownership.”