Bitcoin Quantum Threat May Not Be as Serious as Feared, According to Analyst

According to James Check, only 1.716 million Satoshi-era P2PK coins represent a credible target for quantum attacks.

A report by on-chain analyst James Check is challenging claims that quantum attacks on Bitcoin (BTC) could trigger a catastrophic market collapse.

According to the analysis, even in a worst-case scenario where Satoshi-era coins are hacked and sold, the impact would resemble typical market cycles rather than an existential crisis.

Breaking Down the 6.9 Million Figure

The debate about what could happen to Bitcoin if quantum computers become a reality has grown following research published in March by Google, which outlined how such advanced systems could break cryptographic keys within minutes under certain conditions.

The number that keeps recurring in these discussions is 6.9 million BTC with exposed public keys, and Check’s argument is that treating this as a single, unified threat misrepresents the actual risk.

He splits the exposure into three groups. Around 214,000 BTC sits in Taproot addresses, a newer protocol whose owners are almost certainly alive and capable of moving funds if a post-quantum solution appears. A lot of it is tied up in inscriptions, meaning a quantum attacker would sometimes be cracking cryptography to steal a digital image and a few thousand satoshis.

The bigger pool, roughly 4.996 million BTC, sits in re-used addresses. Most of this belongs to exchanges and custodians.

“Exchanges and custodians have a duty to protect clients’ funds,” Check wrote, and he is confident that institutions like Binance and Coinbase are already working on solutions.

He wants data firms with comprehensive entity labels to do a proper breakdown, expecting the genuinely high-risk portion to shrink dramatically once you strip out active institutions and living users.

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What remains, and what Check considers the only credible target, is the 1.716 million BTC in Satoshi-era Pay-to-Public-Key (P2PK) addresses, assumed by most to be permanently lost coins from Bitcoin’s earliest blocks.

How Much Damage Could a Sale Actually Do?

Check took the worst case at face value and asked whether Bitcoin’s market could absorb it. His answer, backed by several different metrics, is essentially yes, and faster than most people assume.

His “revived supply” data, which tracks coins that have been dormant for months or more re-entering circulation, shows the market routinely absorbs 10,000 to 30,000 BTC per day during bull runs. As such, selling every P2PK coin would be the equivalent of 60 to 90 days of that.

“There’s no doubt that an additional 1.716M BTC market sold will have an appreciable and depressing force on the price,” Check stated while flatly rejecting the claim that it would be fatal.

He also backed the so-called “hourglass” proposal from BIP-360 discussions, capping P2PK transactions at one per block. With around 38,000 P2PK outputs, that would exhaust them in about 264 days, which would be about the same window everyone else would need to migrate under a post-quantum upgrade.

Check ended with a question that was less technical than philosophical. He asked that, given Bitcoin works best if it is widely held, would a situation where Satoshi’s coins end up distributed to buyers instead of being frozen forever really be the disaster people are treating it as?