How Nervos CKB Achieves Quantum Resistance in the Age of Quantum Computing

About CKB and quantum resistance – How Nervos Network prepares for the quantum future

The rapid development of quantum computing is beginning to pose a real and urgent threat to current cryptographic systems.

Unlike classical computers, which operate on binary bits and require astronomical amounts of time to solve cryptographic puzzles, quantum computers use qubits that exist in superposition.

This allows them to perform multiple computations simultaneously and potentially break widely used cryptographic algorithms, including those securing today’s blockchain networks, in a fraction of the time.

Protocols such as ECDSA and RSA – which underlie the security of Bitcoin and many other networks – are especially vulnerable.

As quantum capabilities grow, cryptographers and blockchain developers are racing to implement defenses that will secure networks in a post-quantum world.

Leading this charge is the Nervos Network, whose foundational layer, CKB (Common Knowledge Base), is designed not only with flexibility in mind but with built-in support for quantum-resistant cryptography.

The quantum risk to blockchain

Quantum computing’s threat lies in its ability to undermine the mathematical problems that classical cryptography depends on.

Two major quantum algorithms highlight this risk – Shor’s algorithm and Grover’s algorithm.

Shor’s algorithm can efficiently factor large integers and solve discrete logarithms – the mathematical backbone of RSA and ECDSA.

If a sufficiently powerful quantum computer becomes available, it could extract private keys from public ones, breaking the core of public-key cryptography.

This means that funds stored on traditional UTXO-based networks like Bitcoin – where public keys are revealed once outputs are spent – could be exposed.

Grover’s algorithm, while not as devastating, weakens the effectiveness of hash-based algorithms like SHA-256 by cutting their effective security in half.

This presents challenges to PoW (proof-of-work) mechanisms and Merkle tree structures – both foundational to many blockchain platforms.

With major tech companies such as Google, Microsoft and NVIDIA making rapid advances in quantum computing – Google’s ‘Willow’ processor reportedly hitting over 100 qubits – the time window to prepare is closing fast.

Post-quantum cryptography – The foundation of defense

To stay ahead of quantum threats, researchers have been developing PQC (post-quantum cryptography) algorithms designed to resist attacks from both classical and quantum computers.

Several families of PQC algorithms are currently under review and standardization by NIST.

Lattice-based cryptography – particularly the CRYSTALS-Kyber (ML-KEM) and CRYSTALS-Dilithium (ML-DSA) schemes – has emerged as the front-runner due to its strong security and efficiency.

These two algorithms were formally approved as FIPS 203 and 204 in August 2024.

Hash-based algorithms like XMSS and SPHINCS+ offer strong theoretical guarantees but come with larger signature sizes.

SPHINCS+ in particular has gained traction due to its stateless nature and NIST endorsement.

Adoption is already underway across industries.

Cloudflare, for example, has committed to deploying PQC across its global infrastructure by mid-2025.

In March 2025, NIST also added HQC as another standardized key encapsulation mechanism (KEM), further broadening the toolkit for quantum-resistant systems.

Nervos CKB’s built-in quantum readiness

Unlike many legacy blockchains that are tightly coupled to fixed cryptographic primitives, Nervos CKB was architected with cryptographic agility at its core.

Rather than relying solely on hard forks to adopt new cryptographic methods, CKB uses a flexible scripting system built on its ‘cell’ model.

In CKB, all assets including tokens, smart contracts and user logic are stored as cells, which are programmable and modular.

These cells are not hardcoded with a single cryptographic standard.

Instead, they can be updated or extended with new cryptographic schemes by writing custom lock scripts, without needing to change the base protocol.

This design has already borne fruit – Nervos currently supports SPHINCS+, a NIST-approved, stateless hash-based signature algorithm considered highly secure against quantum attacks.

Developers can use the SPHINCS+ lock script available on the CKB platform to create wallets and contracts that are quantum-resistant today.

This feature puts Nervos ahead of the curve. While most blockchains are still discussing PQC readiness, Nervos has already implemented it.

To this effect, a self-custody and open-source wallet using the SPHINCS+ algorithm is already available on Nervos (Quantum Purse), allowing users the option to protect their assets with PQC.

Nervos’ smart contract environment – the CKB-VM – is based on the RISC-V instruction set, which allows for low-level, crypto-agnostic computation.

Developers aren’t locked into a single language or algorithm.

This flexibility means that as new PQC standards emerge, they can be implemented directly in smart contracts or lock scripts without waiting for a hard protocol fork or VM redesign.

Hybrid approaches and practical transition paths

Nervos also enables hybrid cryptographic schemes, combining both classical and quantum-resistant algorithms.

For instance, developers can construct dual-signature wallets requiring both an ECDSA and a SPHINCS+ signature.

This layered approach provides backward compatibility with current infrastructure while adding quantum resistance.

These hybrid systems offer a smooth transition path – especially valuable in the coming years as the PQC ecosystem matures.

While fully replacing legacy cryptography is the end goal, hybrid schemes allow networks to remain operational and secure during the interim.

Challenges and considerations

Quantum resistance does come with trade-offs.

Post-quantum algorithms – especially hash-based ones like SPHINCS+ – typically result in larger signature sizes sometimes 10 times or more, compared to ECDSA.

This impacts storage, bandwidth and transaction size, which are critical metrics for blockchain performance.

Computational costs also vary. Some algorithms are CPU-intensive, which could increase transaction validation times.

Nervos CKB’s modular approach means developers can test and optimize these trade-offs in specific applications, rather than being forced into one-size-fits-all upgrades.

CKB’s current support for SPHINCS+ allows developers and researchers to evaluate these challenges in production today rather than relying on theory alone.

Conclusion

Quantum computing is no longer a distant theoretical concern.

With quantum hardware progressing rapidly, the cryptographic foundations of today’s blockchain networks are at serious risk.

Blockchains that rely solely on classical algorithms, like ECDSA or RSA, face an eventual and potentially catastrophic compromise.

The Nervos Network, through its CKB layer, presents a powerful example of forward-compatible blockchain design.

With its ‘cell’ model, RISC-V-based VM and support for custom, post-quantum lock scripts like SPHINCS+, Nervos has already laid the groundwork for quantum resistance.

Unlike many networks that will require massive overhauls or hard forks to survive the quantum transition, Nervos is built to adapt.

Whether through hybrid schemes or full PQC migration, it offers developers the tools to stay ahead now – and in the post-quantum future.

To dive deeper into Nervos CKB and quantum resistance, refer to these resources.

• Quantum Computation – New Challenge to CKB’s Security – by Zishuang Han, Cryptape
• Quantum Resistance in Blockchains – Preparing for a Post-Quantum Computing World – by Nervos.org

Connect with the Nervos community on Discord and Telegram.

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