Why are people afraid that quantum computing will kill encryption?

Title: Quantum Isn’t a Threat to Web3. It’s an Upgrade.
Author: DAVID ATTERMANN
Translation: Peggy, BlockBeats

Author: Rhythm BlockBeats

Source:

Repost: Mars Finance

Editor’s Note: The mainstream debate around “Will quantum computing destroy Web3” often misses the core of the actual change. This article points out that quantum is not a threat but a migration of security infrastructure: strong cryptography, perceptible tampering communication, physical-level randomness, and identity verification are gradually becoming foundational capabilities. In this process, blockchains no longer need to repeatedly “compensate” for untrusted network environments at the software layer but can focus more on governance, incentives, and cross-domain coordination—irreducible 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 dedicated to “autonomy, commitments, and coordination.”

Below is the original text:

The mainstream debate about “Will quantum computing kill Web3” actually misses the point. Such framing is itself 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 possible, 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 different 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 prevented the widespread adoption of concepts like JARVIS. The real bottleneck is trust. An assistant that still requires human approval when spending money, accessing sensitive data, or allocating resources cannot be truly autonomous. Once real authorization is involved, and if there is no machine-verifiable, shared method to prove identity, permissions, and compliance, the so-called “autonomy” immediately fails.

Quantum computing, at this critical moment when trust and collaboration become unavoidable, reduces the cost of security.

1. What Quantum Truly Changes (and What It Doesn’t)

When people talk about “quantum,” they usually refer to quantum computers. These are not “faster GPUs” but specialized machines that leverage quantum mechanics to solve certain problems exponentially faster than classical computers.

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

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 is: parts of current public-key cryptography. RSA and elliptic curve cryptography (ECC) are based on mathematical problems that quantum computers are particularly good at solving. This is crucial because cryptography is not just the 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 lies in the timeline, not the direction. Most credible assessments believe that quantum computers capable of “cryptographic destruction” still require 10–20 years to emerge, but no one can fully rule out faster progress or a “quantum leap.”

The most immediate realistic risk: Harvest Now, Decrypt Later (HNDL)

The urgent quantum-related risk is not a sudden collapse of global security systems but the so-called HNDL—collect first, decrypt later.

Attackers can record large amounts of encrypted communications and data today, and when quantum computing becomes sufficiently powerful in the future, decrypt these historical data.

This pattern exposes long-term risks for: government and defense communications, corporate intellectual property and trade secrets, medical data 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 day” but as a gradual infrastructure migration similar to IPv6—slow, uneven, but unavoidable.

This change impacts enterprise and national infrastructure far more than blockchain itself. Blockchain is inherently open; the core secrets to protect are private keys, not historical transaction data. For Web3, quantum computing presents not a survival crisis but a cryptographic upgrade path, not a complete overhaul of the system.

This shift is already visible in mainstream ecosystems. The Ethereum Foundation has recently prioritized post-quantum security at the protocol level, launching dedicated research and testing environments 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 materialize.

2. The Most Overlooked Change: Network Layer Transformation

If quantum computing concerns the mathematical foundations of key protection, quantum communication focuses on 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 in practice is Quantum Key Distribution (QKD): using quantum states to establish a tamper-evident communication channel. The message itself remains classical and encrypted; the real change is that any passive eavesdropping at the physical layer will be detectable.

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 these are used to generate encryption keys or verify communication channels, interception attempts leave detectable traces.

Why does this change system design?

Because much of Web3’s current defense architecture assumes the network channel is adversarial and invisible.

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 have to overcompensate through replication, verification, and economic security measures.

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

Will it scale?

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

3. Trust Challenges in Autonomous Systems

Quantum drives a large-scale security migration across the internet. Over time, strong cryptography and perceptible tampering 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: It’s not enough for an agent to claim it did something; proof is necessary.
Coordination mechanisms: Multi-agent workflows need neutral shared state carriers.
Data provenance: When 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 underpin “commoditized” security capabilities. When security becomes infrastructure, more coordination can happen off-chain with stronger guarantees. Identity and membership will be more aligned with the underlying network structure. For certain workflows, global broadcast replication becomes unnecessary. Blockchain begins shifting from a “pure broadcast system” to a coordination platform for autonomous systems.

4. Frontier Quantum Primitives

The following are long-term possibilities, assuming quantum networks can move beyond niche applications and scale. Once realized, they will strengthen foundational security guarantees and open new protocol design spaces. Like QKD, these primitives aim to free resources for addressing “coordination bottlenecks.”

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

Level 0–10 years:

Physical enforced randomness: Random number generation directly constrained by physical processes, making it unpredictable and unmanipulable.
Cloneless identities and proofs: Identity and authentication based on physical properties, preventing copying and forgery.

Beyond 10 years:

Time synchronization as a primitive: Time becomes a verifiable foundational capability, not just a system parameter.
Verifiable state transitions: Cross-system state changes can be directly proven by underlying mechanisms.

Research frontier (high uncertainty):

Entanglement-based coordination primitives: Using quantum entanglement to establish new collaboration structures.
Minimal trust cross-domain communication: Achieving near-trustless message passing across different trust domains.

Overall, quantum is not “destroying Web3” but accelerating the upgrade of security infrastructure. As security costs decrease, the real bottleneck shifts from cryptography to enabling autonomous systems to reliably collaborate in environments of mutual distrust.

1. Verifiable State Transitions

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

Today’s blockchain systems rely on consensus to enforce non-fungible ownership. Scarcity is a rule defined by protocols, maintained through 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 during transfer and are “consumed” at the moment of transfer. In other words, non-fungibility no longer depends solely on software and protocol constraints but becomes an intrinsic physical property.

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

Hardware-backed custody: regulated anonymous tools, sovereign credentials, or real-world assets controlled by physically unclonable, hardware-verified states.
Lower-trust asset anchoring: some real-world asset bridging mechanisms can rely on physical unclonability rather than solely on multisig or social trust.
Protocol simplification: part of scarcity guarantees can be embedded into lower layers, reducing complexity in protocols that only serve to prevent copying.

2. Entanglement as a Trust Primitive

Blockchain achieves coordination through global replicated state and consensus. Cross-domain interactions often depend on heavy verification or trusted relayers; ordering is usually finalized afterward via blocks and finality.

Quantum entanglement offers a different primitive: establishing shared correlations without a central coordinator. It allows participants to build consistent or aligned views earlier in the process without exposing underlying data.

From this perspective, entanglement is not “faster consensus” but a trust-establishing mechanism at the pipeline front, opening new design space for cross-system and 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.
Reduced upper-layer overcompensation: some “alignment” can be established before heavy global consensus, lowering the cost of adversarial network defenses.

4. Physical Enforced Randomness

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

Quantum processes can generate randomness that is unpredictable and unbiasable under physical assumptions.

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

Cleaner committee and proposer selection: reducing attack surfaces for subtle manipulation strategies.
Fairer ordering and auctions: decreasing gains from timing adversaries, making systems less sensitive to timing games.
More robust incentive mechanisms: making it harder to exploit randomness layers.

4. Cloneless 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 unclonable 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 oracles: proof capabilities are closer to hardware, not just software identities and assertions.
More reliable verifiable computation: execution provenance becomes 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 production windows: reducing asymmetric delays, limiting front-running strategies.
Cleaner cross-domain settlement: tighter time 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 depend on committees, multisigs, relayers, and oracles—all increasing trust assumptions and failure modes.

As entanglement and perceptible tampering 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: more verification closer to the underlying layer reduces catastrophic failure modes.
Cleaner multi-domain ordering: no need for centralized operators, easier to establish shared sequence.
Trust migration down the stack: as foundational guarantees improve, reliance on complex social mechanisms diminishes.

The reason today’s blockchains need to “simulate” scarcity, randomness, identity, ordering, and cross-domain messaging at the software level is because the underlying network and hardware are default untrusted. Quantum networks push some of these capabilities—authenticity, unclonability, tamper detection, randomness, synchronization—into the infrastructure layer.

This is similar to past infrastructure evolutions: TLS brought cryptography into the network layer; Trusted Execution Environments (TEEs) brought trust into hardware; Secure Boot embedded integrity into firmware.

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

5. Counterarguments and Practical Constraints

Even if quantum-secure networks remain limited to strategic corridors, this alone can reshape system architecture standards and assumptions. High-trust communication need not be universal to influence system design: as long as part of the network defaults to perceptible tampering channels, threat models shift upward, and security assumptions broaden.

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 suffices; 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 will not weaken the strategic 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 occur, builders start assuming a new baseline—even if infrastructure rollout remains uneven.

A more realistic evolution might look like this:

Next 5 years: Security capabilities commodify
Post-quantum cryptography gradually expands 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 high-value scenarios like finance, government, and critical infrastructure.
Even if not universal, these upgrades begin shaping how systems are built: teams assume stronger network and cryptographic baselines, focusing more on inter-system interactions, coordination, and rule enforcement among untrusted parties.

5–10 years: Design assumptions shift
With stronger security primitives becoming standard, systems no longer need excessive engineering for adversarial networks or weak cryptography. Underlying platforms will start integrating full execution integrity, hardware proofs, and verification tools—once considered “advanced features.”

At this stage, the change is more about “how people think about system design” than the infrastructure itself. Builders will design assuming a “default secure” environment, with complexity shifting toward how systems interact, enforce permissions, and coordinate across boundaries.

Beyond 10 years: Infrastructure catches up with design paradigms
Quantum-secure channels and perceptible tampering communication will be common in major financial centers, government networks, and critical corridors. By then, most modern systems will have been designed under stronger security assumptions, and infrastructure will finally align with the advanced paradigms that emerged years earlier.

Quantum: Driving the Next Stage of Autonomy

Viewing quantum solely as a threat to Web3 is a misconception. It is more like an accelerant: arriving simultaneously with the emergence of autonomous AI systems in the real world.

It pushes security primitives into the infrastructure layer. Strong cryptography, perceptible tampering channels, and execution integrity become cheaper, more standardized, and less of a competitive advantage. This reduces the “trust cost” at the foundational level, unlocking new design spaces for AI agents to truly possess and exercise real power: verifiable execution, enforceable permissions, and binding commitments that can operate across systems without shared trust.

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

When security becomes infrastructure, the remaining core challenges are the original Web3 problems: establishing autonomy, commitments, and collaboration in inherently untrusted environments.