Quantum computing won't kill cryptocurrencies; it will only push them to become even stronger.

Quantum computing is not a threat but an upgrade to security infrastructure. As strong cryptography, perceptible tamper-evident communication, and physical-level randomness gradually become foundational capabilities, blockchains will no longer need to repeatedly “compensate” for untrustworthy network environments at the software layer. Instead, they can focus more on core issues such as governance, incentives, and cross-domain collaboration. This article is adapted from a piece by David Attermann, organized, translated, and written by BlockBeats.

(Background: a16z long article: What risks does quantum computing pose to cryptocurrencies?)
(Additional context: Under the quantum threat, will privacy coins soon break the “last dance” curse?)

Table of Contents

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• 1. What has quantum truly changed (and what it hasn’t)
  • The most immediate realistic risk: harvest now, decrypt later
  • This is a security migration, not a system collapse
• 2. The most overlooked change: network layer transformation
  • Why this will change system design approaches
  • Will it truly scale?
• 3. Trust issues in autonomous systems
• 4. Frontier quantum primitives
  • Tier 1 (0–10 years)
  • Tier 2 (beyond 10 years)
  • Tier 3 (research frontier, highly uncertain)
• 5. Counterarguments and practical constraints
• 6. How systems will adapt over time
  • Next 5 years: commercialization of security capabilities
  • 5–10 years: design assumptions shift
  • Beyond 10 years: infrastructure catches up with design paradigms
• Quantum: driving the next stage of autonomy

Editor’s note:

Discussions around “Will quantum destroy Web3” often miss the real direction of change. This article points out that quantum is not a threat but a shift in security infrastructure: strong cryptography, perceptible tamper-evident communication, physical-level randomness, and identity proofs are gradually becoming foundational capabilities. In this process, blockchains no longer need to repeatedly “patch” untrustworthy networks at the software level but can focus on governance, incentives, and cross-domain collaboration—core, unavoidable issues.

More importantly, the advent of quantum coincides with the real-world deployment of autonomous AI systems. When security becomes infrastructure, Web3 truly enters a mature stage of “autonomy, commitments, and coordination.”

Below is the original text:

Mainstream debates about “Will quantum computing kill Web3” are actually missing the point. Such framing is inverted. Quantum computing does not make digital systems less secure; on the contrary, it pushes security further down into the underlying infrastructure. As new cryptographic standards are gradually adopted and new secure communication methods become feasible, foundational security capabilities will become cheaper and more standardized across the internet.

Meanwhile, AI systems are shifting from “thinking” to “acting.” When intelligent assistants no longer just answer questions but can book flights, transfer funds, and manage resources, the real challenge shifts accordingly. The question is no longer whether AI can generate good answers, but whether software can safely act across systems and organizations that do not trust each other. How to prove what AI has done, where data comes from, and what it is authorized to do is becoming the core constraint.

This is the same fracture line that has kept JARVIS-like visions from materializing. The real bottleneck is trust. An assistant that still requires human approval for spending, accessing sensitive data, or allocating resources—hardly autonomous. Once real authorization is involved, without a machine-verifiable, shared way to prove identity, permissions, and compliance, “autonomy” immediately fails.

And at this moment—when trust and coordination become unavoidable issues—quantum computing lowers the cost of security.

1. What has quantum truly changed (and what it hasn’t)

When people talk about “quantum,” they usually mean quantum computers. These are not “faster GPUs,” but specialized machines leveraging quantum mechanics, capable of solving certain problems exponentially faster than classical computers.

They excel at: factoring large numbers, solving discrete logarithms, certain optimization and simulation problems.

They are not good at: general-purpose computing, running large software systems, replacing cloud infrastructure, or training AI models.

So, what exactly will quantum computing break?

The answer: parts of current public-key cryptography. RSA and elliptic curve cryptography (ECC) are based on mathematical problems that quantum computers are most efficient at solving. This is critical because cryptography is not just the underlying primitive of blockchain; it is the trust foundation of the entire internet—login mechanisms, digital certificates, signatures, key exchanges, identity systems—all depend on it.

The real uncertainty is about timing, not direction. Most credible assessments suggest that quantum computers capable of breaking cryptography are still 10–20 years away, but no one can fully rule out faster progress or sudden breakthroughs.

The most immediate realistic risk: harvest now, decrypt later

The most urgent quantum-related risk is not a sudden collapse of global security systems but the so-called HNDL (Harvest Now, Decrypt Later).

Attackers can record large volumes of encrypted communications and data today, then decrypt them in the future when quantum capabilities are sufficient.

This mode poses long-term exposure risks for: government and defense communications, corporate intellectual property and trade secrets, medical and personal privacy records, legal and financial archives.

Therefore, post-quantum cryptography (PQC) is being seriously addressed by governments, cloud providers, and regulated industries today. Data transmitted now often needs to remain confidential for decades; assuming it can be decrypted in the future invalidates current security guarantees.

This is a security migration, not a system collapse

Post-quantum cryptography does not require quantum hardware. It is fundamentally a software and protocol upgrade—covering TLS, VPNs, wallets, identity systems, and signatures. This will not happen on a single “switch-over” day but as a gradual infrastructure migration—slow, uneven, but unavoidable.

This shift impacts enterprise and national infrastructure far more than it does blockchains. Blockchains are inherently open systems; the core secret to protect is the private key, not historical transaction data. For Web3, quantum computing presents not a survival crisis but a cryptography upgrade path, not a complete overhaul.

This transition is already visible in mainstream ecosystems. The Ethereum Foundation has recently prioritized post-quantum security at the protocol layer, initiating dedicated research and testing around quantum-resistant signatures, account models, and transaction mechanisms. This signals that risk awareness has shifted from “a future problem” to “an ongoing infrastructure migration,” even though large-scale quantum hardware has yet to emerge.

2. The most overlooked change: network layer transformation

If quantum computing concerns the mathematics underpinning key protection, quantum communication concerns the trust model of the network itself.

Quantum communication does not mean transmitting application data via quantum computers. Although it has various implementations (discussed below), the core application today is quantum key distribution (QKD): using quantum states to establish a tamper-evident communication channel. The message remains classical and encrypted; what changes is that any passive eavesdropping at the physical layer can be detected.

This is not a faster network but a trust mechanism that cannot be covertly infiltrated.

Some quantum properties cannot be copied or observed without disturbance. When used for generating encryption keys or verifying channels, interception becomes detectable. Any eavesdropping leaves observable traces.

Why this will change system design approaches

This is important because much of Web3’s current defense architecture assumes: network channels are adversarial and opaque.

Traffic can be silently intercepted; man-in-the-middle attacks are hard to detect; trust at the network layer is extremely weak.

Therefore, upper-layer systems compensate excessively through replication, verification, and economic security mechanisms.

If the infrastructure layer itself embeds guarantees of channel integrity, quantum communication effectively reduces the cost of maintaining secure channels. This point is often overlooked in mainstream “quantum doom” narratives.

Will it truly scale?

Like quantum computing, widespread adoption of quantum key distribution (QKD) may still take 10–20 years. But the timeline could accelerate if breakthroughs occur—such as in quantum repeaters, satellite networks, or integrated photonic technologies.

3. Trust issues in autonomous systems

Quantum drives a security migration across the internet. Over time, strong cryptography and perceptible tamper-evident channels will become infrastructure, not differentiators.

But the real bottleneck for “collaboration” is the rise of autonomous AI agents.

Autonomous systems cannot rely on informal trust or institutional shortcuts like humans do. They require:

Verifiable execution: cannot just trust an agent’s claim; proof is needed.

Coordination mechanisms: multi-agent workflows need neutral shared state carriers.

Data provenance: as synthetic and adversarial data proliferate, source verification is critical.

Commitment mechanisms: agents must make binding, enforceable commitments others can rely on.

Quantum networks do not directly solve coordination problems, but they will embed security capabilities at the foundational level. When security becomes part of infrastructure, more coordination can happen off-chain with stronger guarantees. Identity and membership relationships will be more tightly integrated into the network layer. For certain workflows, global broadcast replication becomes unnecessary. Blockchains will evolve from “pure broadcast systems” to coordination platforms for autonomous systems.

4. Frontier quantum primitives

These are longer-term possibilities, contingent on quantum networks scaling beyond niche applications. Once realized, they will reinforce bottom-layer security guarantees and open new protocol design spaces. Like QKD, these primitives aim to free resources from “coordination bottlenecks.”

Some are closer to practical deployment; others are signals of future trust mechanism evolution.

Tier 1 (0–10 years)

Physical enforced randomness: random numbers generated directly from physical processes, unpredictable and unmanipulable.

Uncopyable identities and proofs: identity and authentication based on physical properties, preventing duplication and counterfeiting.

Tier 2 (beyond 10 years)

Time synchronization as a primitive: time becomes a verifiable foundational capability, not just a system parameter.

Verifiable state transfer: cross-system state changes can be directly proven by underlying mechanisms.

Tier 3 (research frontier, highly uncertain)

Entanglement-based coordination primitives: using quantum entanglement to establish new forms of collaboration.

Fully trust-minimized cross-domain communication: message passing across trust boundaries with minimal assumptions.

Overall, quantum is not “destroying Web3” but accelerating the upgrade of security foundations. When security costs drop, the real bottleneck shifts from cryptography to how autonomous systems can reliably coordinate in untrusted environments.

1. Verifiable state transfer

From “software-enforced scarcity” to “physical impossibility of copying”

In today’s blockchains, non-fungible ownership is achieved through global consensus. Scarcity is a rule set by protocols, maintained via replication and consistency across nodes. The ledger exists largely to prevent double-spending or copying of the same state.

Quantum teleportation introduces a fundamentally different primitive: states can be transferred but cannot be copied, and are “consumed” at the moment of transfer. In other words, non-copyability becomes a physical property, not just a protocol rule.

Why is this important? How will it change system design?

Hardware-backed attestations: regulated anonymous tools, sovereignty-level credentials, or real-world assets can be controlled via states with physical proof capabilities.

Lower trust assumptions for asset anchoring: some real-world asset bridges can rely on physical non-copyability rather than solely on multisig or social trust.

Protocol simplification: parts of scarcity guarantees are embedded into lower layers, reducing complexity in protocols that only serve to prevent copying.

2. Entanglement as a trust primitive

Blockchains achieve coordination via global state replication and consensus. Cross-domain interactions often rely on heavy verification or trusted relays; ordering is confirmed post hoc via blocks and finality.

Quantum entanglement offers a different primitive: establishing shared correlations without a central coordinator. It allows participants to build consistency or aligned properties earlier, without exposing underlying data.

From this perspective, entanglement is not “faster consensus” but a trust constraint established at the pipeline front end, opening new design space for cross-system, cross-domain collaboration.

Why is this important, and how will it change system design?

Earlier synchronization: sequencers can establish a shared view of “ordering commitments” before final settlement.

Cleaner cross-domain alignment: multiple domains can prove they observed the same event stream without relying on a single relayer.

Reducing upper-layer overcompensation: some “alignment” can be established before heavy global arbitration, lowering the cost of adversarial network defenses.

4. Physical enforced randomness

From gameable pseudo-random beacons to physically backed unpredictability. Randomness underpins validator selection, block proposer election, committee sampling, auctions, and incentives. Today’s randomness is protocol-constructed, leaving room for manipulation or bias.

Quantum processes can generate randomness that is physically unpredictable and unbiasable.

Why is this important, and how will it change system design?

Cleaner committee and proposer selection: reducing attack surfaces for subtle manipulation.

Fairer ordering and auctions: decreasing benefits from timing adversaries, making systems less sensitive to timing games.

More robust incentive mechanisms: making it harder to exploit randomness layers.

4. Uncopyable identities and proofs

From “keys as identity” to “devices as identity.” Today, Web3 identity is almost synonymous with “holding a key.” Sybil resistance mainly relies on economic costs or social heuristics. Node identities are loosely anchored at the software level.

Quantum states cannot be copied. When combined with hardware attestation, this can enable uncopyable device identities and stronger remote proofs: proving that a message or computation indeed originates from a specific physical endpoint.

Why is this important, and how will it change system design?

Stronger endpoint guarantees: messages and execution claims can be bound to specific physical environments.

Reduced reliance on relayers and oracle trust: proof capabilities are closer to hardware, not just software identities.

More reliable verifiable computation: execution provenance is harder to forge.

5. Making time synchronization a primitive

From “soft clocks” to “protocol-level time.” Blockchain’s handling of time is essentially a soft assumption. Slot timing and ordering can be exploited; small delays can drive MEV. Quantum-enhanced clock synchronization enables tighter coordination over long distances.

Why is this important, and how will it change system design?

Fairer block windows: reducing asymmetric delays, limiting front-running.

Cleaner cross-domain settlement: tighter timing windows reduce race conditions.

More stable ordering: protocol timing becomes less sensitive to network jitter.

6. Minimal trust cross-domain collaboration

From “everywhere committees” to “physically backed message passing.” Cross-chain security remains one of Web3’s biggest operational risks. Bridges rely on committees, multisig, relays, and oracles—each adding trust assumptions and failure modes.

As entanglement and perceptible tamper-evident channels mature, different domains can prove they observed the same commitments or event streams with fewer social trust assumptions.

Why is this important, and how will it change system design?

Smaller trust sets for bridges: with verification closer to the physical layer, catastrophic failures decrease.

Cleaner multi-domain ordering: no need for centralized operators, easier to establish shared sequence.

Security stack migration downward

Today’s blockchains need to “simulate” scarcity, randomness, identity, ordering, and cross-domain messaging at the software level because the underlying network and hardware are assumed untrusted. Quantum networks embed aspects of authenticity, non-copyability, tamper detection, randomness, and synchronization into the infrastructure layer.

This is similar to past infrastructure evolutions: TLS brought cryptography into the network layer; TEE introduced trust into hardware; secure boot brought integrity into firmware.

Blockchains will not become obsolete; they will no longer bear the heavy burden of repeatedly implementing trust primitives in software but will instead focus on the unavoidable core issues: governance, incentives, collusion resistance, and adversarial shared states.

5. Counterarguments and practical constraints

Even if quantum-secure networks are limited to strategic corridors, this alone can reshape the entire tech stack’s assumptions and design principles. High-trust communication need not be universal to influence system architecture: as long as some parts of the network are assumed to provide perceptible tamper-evidence, threat models shift upward, and foundational security assumptions begin to evolve.

In reality, quantum-secure communication remains expensive, fragile, and limited in coverage. Hardware deployment and maintenance are complex, and integration with existing internet infrastructure is challenging. For many use cases, post-quantum cryptography alone may suffice; thus, quantum-secure links are more likely to be concentrated in high-value environments: government networks, financial infrastructure, and critical national systems.

Ultimately, a hybrid trust landscape will emerge: some corridors with stronger default guarantees, while the open internet remains adversarial.

This uneven rollout does not weaken the architectural shift but may cause it to appear “tilted.”

6. How systems will adapt over time

Large infrastructure shifts rarely happen all at once. System design changes often precede widespread adoption of new tech, especially in security. Once new standards are adopted and early deployments emerge, builders start assuming a new baseline—even if infrastructure rollout remains uneven.

A more realistic evolution might look like this:

Next 5 years:
Post-quantum cryptography becomes standard in cloud services, enterprises, and regulated sectors. “Quantum security” becomes part of default security checklists, not a niche feature. Early quantum-secure links appear in finance, government, and critical infrastructure.

Even if not universal, these will influence system architecture: teams will assume stronger network and cryptographic baselines, focusing more on inter-system interactions, coordination, and rule enforcement among untrusted participants.

5–10 years:
As stronger primitives become standard, systems will no longer need to overengineer for adversarial networks or weak cryptography. Underlying platforms will integrate integrity verification, hardware attestation, and validation tools—once considered “advanced features.”

At this stage, the change shifts from infrastructure to mindset: designing systems assuming “security is pre-established,” with complexity moving toward how systems interact, manage permissions, and coordinate across boundaries.

Beyond 10 years:
Quantum-secure channels and perceptible tamper-evident communication will be common in major financial hubs, government networks, and critical corridors. By then, most modern systems will have been redesigned under stronger security assumptions, and infrastructure will finally catch up with the design paradigms that have been emerging for years.

Quantum: driving the next stage of autonomy

Framing quantum as a threat to Web3 is actually backwards. Quantum is more like an accelerator: it arrives simultaneously with autonomous AI systems entering the real world.

It pushes security primitives into infrastructure layers. Strong cryptography, perceptible tamper-evident channels, and execution integrity become cheaper, more standardized, and less of a differentiator. This reduces the “trust cost” at the base layer, unlocking new design spaces for building AI agents with genuine power: verifiable execution, enforceable boundaries, and commitments that can be bound across systems without shared trust.

Quantum will not kill Web3; it will force Web3 to grow up.

When security becomes infrastructure, the remaining challenge is the core problem Web3 was originally meant to solve: establishing autonomy, commitments, and coordination in inherently untrusted environments.