Quantum computers still cannot break Bitcoin, but several major blockchains are preparing for a future in which they might.
In the past week, Aptos proposed post-quantum signature support as Solana tested quantum-resistant transactions. Meanwhile, parts of the Bitcoin community renewed calls to accelerate work on quantum-safe upgrades.
These developments point to a growing anxiety across crypto. Investors argue that dismissal of quantum risk by influential voices is weighing on Bitcoin’s (BTC) price, which has dropped 24% over the past three months.
While altcoin blockchains are experimenting with post-quantum protections through opt-in upgrades and test networks, Bitcoin remains divided over how publicly and urgently it should address quantum risks.
How blockchains are preparing without sounding the alarm
Ethereum has been clear about why quantum computing is now being treated as an engineering problem rather than a distant hypothetical.
Ethereum co-founder Vitalik Buterin has argued that even a low-probability outcome demands early preparation when the cost of failure is high and the time required to migrate global systems is measured in years.
Citing forecasting models, he has said there is roughly a 20% chance that quantum computers capable of breaking today’s public-key cryptography could emerge before 2030, with a median estimate closer to 2040. Buterin reportedly said no machines exist today that can break Bitcoin or Ethereum, but waiting for certainty is itself risky, as migrating a global network to post-quantum schemes can take years.
That framing has begun to echo across other major blockchains, particularly those that can experiment without reopening foundational debates.
Aptos has proposed adding post-quantum signature support at the account level through an opt-in upgrade that would leave existing accounts untouched. The proposal relies on a hash-based signature scheme and is positioned as future-proofing rather than a reaction to an imminent threat. Users can adopt the new scheme if they choose, without forcing a network-wide migration.
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Solana has taken a similar posture through testing rather than deployment. In partnership with post-quantum security firm Project Eleven, the network recently ran a dedicated testnet using quantum-resistant signatures to assess whether such schemes can be integrated without undermining performance or compatibility.
Bitcoin’s quantum debate is really about trust
Bitcoin relies on elliptic curve cryptography to verify ownership. Control over funds is proven through a private key, while only the corresponding public key is revealed onchain.
In theory, a sufficiently powerful quantum computer running Shor’s algorithm could work backwards from a public key to recover the private one, allowing an attacker to spend funds without triggering any obvious signs of theft. From the network’s perspective, those coins would simply move as if their owner had decided to transact.
Even proponents of post-quantum upgrades generally acknowledge that cryptographically relevant machines are still years away. But the dispute in Bitcoin’s community is about how Bitcoin should respond to a risk that is distant, uncertain and difficult to detect once it materializes.
On one side, developers and longtime Bitcoin cryptographers argue that framing quantum computing as an urgent concern does more harm than good.
Blockstream CEO Adam Back has repeatedly dismissed near-term quantum fears, stressing that practical quantum attacks remain decades out. He claimed that amplifying quantum risks fuels panic and encourages markets to price in a threat that does not yet exist.
On the other side, investors and researchers argue that even a low-probability outcome matters for an asset whose value depends on long-term confidence. Castle Island Ventures partner Nic Carter has described the outright dismissal of quantum risk by influential developers as bearish.
Craig Warmke of the Bitcoin Policy Institute has similarly warned that perceived complacency is pushing some capital to diversify away from Bitcoin regardless of whether the underlying technical fears are precisely articulated.
That tension explains why proposals such as Bitcoin Improvement Proposal 360, which would introduce quantum-resistant signature options, provoke outsized reactions despite their early and tentative status.
Related: Bitcoin decouples from stocks in second half of 2025
Supporters see early work as a way to reduce uncertainty and signal preparedness. Critics see the same discussion as legitimizing a speculative threat and inviting confusion about Bitcoin’s resilience.
Why quantum uncertainty matters differently for Bitcoin
Quantum computers today cannot break Bitcoin or any major blockchain. What is already happening is that uncertainty around quantum risk is influencing how different networks choose to communicate and how investors interpret those choices.
Outside Bitcoin, post-quantum work has been framed as infrastructure. Opt-in upgrades and test networks allow blockchains to signal preparedness without forcing users or markets to reassess present-day security assumptions. That approach limits the reputational cost of early preparation while preserving flexibility if timelines change.
Bitcoin operates under different constraints. Because its value is closely tied to long-term assurances about security and durability, discussions about future-proofing its cryptography tend to attract immediate scrutiny. What might be treated as routine contingency planning elsewhere is more easily read as a comment on Bitcoin’s fundamentals.
Influential voices related to Bitcoin worry that emphasizing distant risks invites misunderstanding and panic. Investors worry that minimizing those risks signals a lack of contingency planning. Both sides are responding to how confidence is shaped in the absence of clear timelines.
The quantum debate suggests that for Bitcoin, managing how long-term risks are discussed may matter as much as managing the risks themselves.
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