Post-Quantum Blockchain Architecture Analysis: NEAR Cryptographic Upgrades and Kaspa Consensus Defense Mechanism

Quantum computing’s threat to blockchain has been discussed within the crypto industry for years. But the change happening in 2026 is that this narrative is being translated into concrete engineering actions. On May 7th, NEAR Protocol officially announced the integration of post-quantum cryptography into its network; meanwhile, on May 5th, Kaspa completed its most significant hard fork upgrade in its mainnet history. Two blockchains, two radically different paths—one actively reconstructing security from the cryptographic foundation, the other seeking systemic defense through a unique consensus mechanism design.

Behind these moves lies a series of accelerating threat signals. On March 30, 2026, Google Quantum AI, in collaboration with Ethereum Foundation researchers and Stanford cryptography professors, published a groundbreaking white paper that systematically evaluated the resources needed for quantum computers to crack cryptocurrency cryptography—finding that breaking Bitcoin and Ethereum’s reliance on 256-bit elliptic curve cryptography would require fewer than 500k physical qubits, reducing previous academic estimates by about 20 times. On April 24, Italian independent researcher Giancarlo Lelli used a publicly accessible quantum computer to successfully crack a 15-bit elliptic curve private key in approximately 45 minutes, earning a 1 BTC bounty set by Project Eleven—one of the largest publicly demonstrated quantum attacks on elliptic curve cryptography to date. The outline of quantum threats is moving from laboratory papers toward verifiable engineering boundaries.

Threat Landscape: How Close Is Quantum Computing?

Before dissecting the two technical paths, it’s necessary to clarify the current evolution coordinates of quantum threats. The threat posed by quantum computing to blockchain is not homogeneous; rather, it involves multiple attack surfaces and varying levels of urgency.

The core threat comes from Shor’s algorithm. This quantum algorithm can factor elliptic curve cryptography (ECDSA) in polynomial time, directly impacting the digital signature schemes that most current blockchains rely on. Once quantum computers capable of this are mature, attackers could derive private keys from public keys and thus control associated assets.

According to Decrypt on May 11, 2026, multiple crypto companies are adopting NIST-approved post-quantum cryptography algorithms to upgrade user wallets and custodial infrastructure, aiming to deploy quantum-safe protections before protocol layer upgrades on blockchains like Bitcoin and Ethereum are completed. The industry is accelerating.

Another threat is the so-called “Harvest Now, Decrypt Later” strategy. Attackers are currently collecting and storing encrypted data at scale, waiting for future quantum capabilities to decrypt it. For blockchains, this means every transaction broadcast today could be stored and decrypted in the future.

Project Eleven’s report published on May 10, 2026, warns that if quantum threats become real by 2030, starting migration in 2029 may be too late. The report also notes that the main obstacle to transitioning to post-quantum cryptography is coordination, not technology—large systems may require five to over ten years for transition, and blockchains need simultaneous action from users, exchanges, custodians, wallet providers, and miners.

It’s worth noting that not all industry participants agree on this urgency. BitGo CEO publicly rebutted the 2030 timeline on May 10, 2026, calling the report “company relying on quantum panic.” There are clear disagreements within the industry regarding the urgency of the threat.

Additionally, industry research firms have published quantum vulnerability analyses of mainstream public chains, with Bitcoin considered among the most vulnerable. Google Quantum AI’s research ranks Cardano as the second most prepared blockchain against quantum attacks globally. Against this backdrop, NEAR and Kaspa have chosen different defense strategies.

NEAR Path: Protocol-Level Integration of Post-Quantum Cryptography

NEAR Protocol has chosen an active defense path starting from the cryptographic foundation.

According to NEAR’s official team, NEAR currently supports two signature schemes: EdDSA and ECDSA, both of which are not quantum-safe. The core of this update is adding FIPS-204 (ML-DSA, formerly CRYSTALS-Dilithium), a lattice-based post-quantum signature scheme approved by NIST, which was officially standardized as one of NIST’s first post-quantum cryptography standards in August 2024.

FIPS-204 belongs to lattice digital signature algorithms. Lattice cryptography is considered one of the most promising directions for post-quantum cryptography, balancing security and performance. NIST officially approved standards FIPS 203, 204, and 205 in August 2024, providing a concrete technical baseline for the industry.

The key design highlight of NEAR’s upgrade is the user experience of key rotation. Once implemented, any NEAR account holder can perform a single transaction to switch to a post-quantum secure signature scheme—without the need for complex address migration. This design leverages NEAR’s account model architecture—each account is controlled via rotatable “access keys,” not permanently bound to specific key pairs. Unlike Bitcoin or Ethereum users who need to create new addresses and transfer assets, NEAR’s key rotation is just a chain transaction.

The NEAR early architecture team incorporated post-quantum security considerations from the outset. This long-term vision has now become a structural advantage that sets NEAR apart from other public chains.

It’s also important to note the wallet ecosystem’s synchronized follow-up. Near One has partnered with hardware wallet makers like Ledger to jointly plan post-quantum support solutions. Since most hardware wallets currently do not support quantum-safe signatures, Near One’s strategy is to work directly with manufacturers to accelerate new solutions into the market.

On the cross-chain layer, NEAR’s chain signature MPC network already supports threshold signatures for over 35 chains. The Defuse team is developing quantum-safe cross-chain signing solutions for NEAR Intents users, aiming to provide a quantum-secure environment for ecosystems slower to migrate to post-quantum cryptography.

The plan is to launch the testnet version by the end of Q2 2026, with mainnet deployment following after security audits and community coordination.

The NEAR team also raises a more long-term question: if quantum computers can crack elliptic curve encryption, how can ownership of unphysical assets be proven? Near One warns that this could trigger a broader crisis of crypto asset ownership.

Kaspa Path: Systemic Defense via GHOSTDAG Consensus Mechanism

Unlike NEAR’s bottom-up cryptographic approach, Kaspa’s post-quantum narrative is built on the unique advantages of its consensus layer and architecture design.

Kaspa’s core innovation is centered on the GHOSTDAG protocol. Unlike traditional blockchains that process blocks sequentially and isolate parallel blocks, GHOSTDAG allows blocks to coexist and be ordered simultaneously. It identifies a set of “blue” blocks to order parallel blocks and deterministically resolve conflicts, preventing the “orphaned block” runaway problem common in high-block-rate chains.

From a quantum security perspective, GHOSTDAG and blockDAG architectures offer unique security properties at two levels. First, the parallel block generation mechanism significantly raises attack barriers. Kaspa’s mainnet currently produces 10 blocks per second, with a future goal of 100. Even with quantum computing power, such high block rates make it extremely difficult for an attacker to control the majority hash power in a short time, as honest nodes can continuously produce large numbers of blocks. Second, the GHOSTDAG protocol provides high security by combining PoW and DAG-based consensus, increasing resistance to 51% attacks.

Meanwhile, Kaspa community developers have proposed quantum-resistant wallet upgrade plans. A developer named bitcoinSG suggested switching from current P2PK addresses to P2PKH-Blake2b-256-via-P2SH, hiding the public key before funds are spent to reduce quantum attack exposure. This wallet-layer change is backward compatible and does not require hard forks.

On May 5, 2026, Kaspa completed a Covenant-Centric hard fork, introducing native assets, enhanced covenants, and zero-knowledge verification, transforming Kaspa from a fast payment system into a programmable smart contract platform. While not directly targeting quantum security, this upgrade expands Kaspa’s programmable capabilities and lays a more flexible foundation for future security upgrades.

However, Kaspa’s quantum resilience is not invulnerable. An in-depth analysis reveals a “quantum Achilles’ heel”: Kaspa relies on UTXO commitment mechanisms using MuHash, which is based on elliptic curve discrete logarithm problems—precisely the kind that Shor’s algorithm can crack. If an attacker can reverse-engineer these commitments, they could construct a different UTXO set that still matches the original MuHash commitment, effectively forging the chain state. This risk is especially pronounced after data pruning—Kaspa clears old data to maintain efficiency, meaning nodes rely solely on these commitments rather than full transaction history for validation.

Addressing this involves a dilemma: adopting post-quantum cryptography could double block header size, impacting efficiency; relying on archival nodes introduces trust assumptions, weakening decentralization.

Additionally, Kaspa’s former core contributor Shai Wyborski has publicly stated that no PoW system currently can fully resist quantum mining attacks—highlighting a systemic vulnerability shared across PoW networks.

Comparing the Two Paths: Facts, Strengths, and Limitations

The table below, based on current available information, offers a structured multi-dimensional comparison of NEAR and Kaspa’s two quantum defense paths:

From this comparison, the two paths’ core distinctions are clear:

• NEAR’s approach is a cryptography replacement strategy, with high standardization, clear security guarantees, and user-friendly migration, but currently limited to signature layer; full consensus-layer quantum security requires further work.

• Kaspa’s approach is an architecture resilience strategy, leveraging high block production rates to raise attack costs, with PoW hash functions offering some resistance, but its reliance on elliptic curve commitments presents a fundamental soft spot that is not easily mitigated without protocol-level changes.

Industry Cross-Section: The Quantum Security Race Landscape

NEAR and Kaspa are not isolated; their choices must be viewed within the broader industry quantum security race.

Mainstream public chains show a layered pattern of quantum security deployment. Ethereum Foundation launched the “Post-Quantum Ethereum” site in March 2026, elevating quantum safety to a top strategic priority, and assembled a dedicated quantum security team. Coinbase announced a quantum advisory committee, and NIST has set timelines for migration. Ethereum’s roadmap suggests Layer 1 upgrades might occur around 2029, with full execution possibly later.

In terms of readiness rankings, Google Quantum AI’s report ranks Cardano as the second most prepared blockchain against quantum attacks globally, owing to its structural advantages for future post-quantum migration. Conversely, Ethereum and Solana are viewed as having the most attack surface, since their public keys are always visible.

A notable industry trend is the parallel and competitive push at the wallet and protocol layers for quantum-safe upgrades. Many crypto firms are adopting NIST-approved post-quantum algorithms to upgrade wallets and custodial infrastructure. Some focus on wallet-layer upgrades, others insist that only protocol-layer changes can fully protect users. As Silence Laboratories CEO warns: “If wallets upgrade to post-quantum but the blockchain itself does not, that’s not sustainable.”

The emerging consensus is that quantum security will no longer be optional but a necessary infrastructure upgrade. NEAR’s architectural advantages give it a head start, while Kaspa must balance performance optimization with security upgrades.

Risks and Limitations: Boundaries of Both Paths

While recognizing each path’s strengths, it’s crucial to acknowledge their substantive risks.

NEAR’s key challenges include four aspects:

1. The long-term security of lattice cryptography, despite NIST standardization, remains under active discussion; its security proof system is less mature than hash-based signatures.

2. NEAR’s post-quantum upgrade currently covers only account signatures; consensus mechanisms, validator communication, and block synchronization still need ongoing post-quantum adaptation.

3. The larger size of FIPS-204 signatures (e.g., ~2.4 KB) could significantly increase storage and bandwidth costs, impacting node validation and network scalability.

4. Near One’s relatively centralized governance, while efficient, may pose risks if the chosen technical path proves suboptimal or if future corrections are needed.

Kaspa’s fundamental challenges include:

• The reliance on MuHash commitments based on elliptic curve discrete log problems, which are vulnerable to Shor’s algorithm. Once quantum computers reach critical capability, the validity of Kaspa’s chain state could be compromised.

• Data pruning—Kaspa’s approach to maintain efficiency—exacerbates this risk, as nodes depend solely on commitments rather than full transaction history, making the system potentially forgeable.

• Transitioning to fully quantum-resistant protocols would likely increase block header size and complexity, impacting performance.

• The absence of a PoW system fully resistant to quantum attacks remains a systemic vulnerability, as acknowledged by former core contributors.

Conclusion

2026 marks a pivotal year for blockchain’s quantum security transformation. NEAR and Kaspa exemplify two distinct philosophies—one actively replacing cryptographic primitives at the protocol level, the other leveraging architectural features to raise attack costs. These paths are not mutually exclusive but reflect underlying design philosophies and security priorities.

NEAR’s approach benefits from standardization, clarity, and user-friendly migration, with its forward-looking architecture already translating into tangible competitive advantages amid accelerating threats. Kaspa’s high block rate and DAG-based consensus provide inherent resilience but face soft vulnerabilities rooted in elliptic curve cryptography.

Quantum security is shifting from an optional feature to an essential infrastructure upgrade. The correctness of technical choices and the efficiency of execution will profoundly influence the long-term competitiveness of public chains. For industry participants, understanding each chain’s position and strategic path is fundamental to making rational judgments in this race.