--- title: Is Nervos CKB quantum-safe? chain: Nervos CKB ticker: CKB hardy_score: 75.5 rank: 3 of 23 tier: "2: Shipping" url: "https://hardyindex.com/chains/nervos-ckb" updated: 2026-08-11 methodology_version: 1.1 --- # Is Nervos CKB quantum-safe? **Hardy Score 75.5 / 100. Rank 3 of 23. Tier 2: Shipping. As of 11 August 2026.** Partly, and by user choice rather than by default. Nervos CKB does not hardcode a signature algorithm into its consensus rules. Signature verification runs as a Lock Script on a RISC-V virtual machine, so a post-quantum scheme can be added without changing the protocol. The CKB team used that property to build a SPHINCS+ lock script, audited by ScaleBit, and began deploying it on mainnet in 2025 alongside a wallet that uses it. A CKB holder can therefore move funds to a quantum-resistant address today, permissionlessly and without a fork. What CKB has not done is make that the default: ordinary CKB addresses still use secp256k1, which a sufficiently large quantum computer would break, and the large majority of supply still sits under those classical locks. > This is a security-readiness assessment, not investment advice. ## Summary An audited SPHINCS+ lock script is deployed on CKB mainnet, so users can hold funds under a NIST-standardised post-quantum signature today without a hard fork. ## Where we are making a judgement call CKB sits in Tier 2 on the strength of an opt-in lock script rather than a protocol-level default. We treat a scheme that protects real mainnet funds today as shipped, even when adoption is small, because that is the literal test the tier sets. Readers who weight default protection more heavily than availability should read this placement as generous. ## Score breakdown | # | Dimension | Score | Weight | Contribution | |---:|---|---:|---:|---:| | 1 | Signature scheme | 6/10 | 30% | 18.0 | | 2 | Deployment stage | 8/10 | 25% | 20.0 | | 3 | NIST alignment | 10/10 | 15% | 15.0 | | 4 | Migration path | 9/10 | 15% | 13.5 | | 5 | Exposure | 5/10 | 10% | 5.0 | | 6 | Verification | 8/10 | 5% | 4.0 | | | **Hardy Score** | | | **75.5** | ### 1. Signature scheme: 6/10 SPHINCS+ is available on mainnet as an audited, production-ready lock script supporting twelve parameter sets, and a desktop wallet ships with it. It is opt-in rather than the default, and normal CKB addresses remain secp256k1. Source: https://docs.nervos.org/docs/ckb-features/native-quantum-resistance ### 2. Deployment stage: 8/10 Tier 2: Shipping. A post-quantum signature scheme protects real funds on CKB mainnet today and users can migrate to it now, which is the defining test for this tier. Source: https://docs.nervos.org/docs/ckb-features/native-quantum-resistance ### 3. NIST alignment: 10/10 SPHINCS+ was standardised by NIST as SLH-DSA in FIPS 205 in August 2024. CKB is using a finalised standard rather than a candidate, which no other chain in this index does for a scheme that is live on mainnet. Source: https://csrc.nist.gov/pubs/fips/205/final ### 4. Migration path: 9/10 CKB's migration is the cleanest in the index. A user creates an address referencing the new lock script's code hash and transfers assets to it. No hard fork is required, the network does not need to coordinate, old addresses keep working, and the upgrade can proceed gradually and permissionlessly. Source: https://docs.nervos.org/docs/ckb-features/native-quantum-resistance ### 5. Exposure: 5/10 CKB uses a cell model in which addresses commit to a lock script hash, so a public key is not revealed until an output is spent. That limits exposure compared with account-model chains where the address is the public key, but the majority of supply still sits under secp256k1 locks and every spent cell has revealed its key. Source: https://docs.nervos.org/docs/ckb-features/native-quantum-resistance ### 6. Verification: 8/10 The quantum-resistant lock script is open source and completed a security audit by ScaleBit. The claim is checkable on-chain and in the public repository rather than resting on marketing. Source: https://github.com/nervosnetwork/quantum-resistant-lock-script ## Signature scheme - **On mainnet today:** secp256k1 by default; SPHINCS+ available via an on-chain lock script - **Post-quantum scheme:** SPHINCS+ (SLH-DSA), twelve selectable parameter sets - **NIST standard:** FIPS 205 (SLH-DSA), finalised August 2024 - **Readiness tier:** Tier 2: Shipping. Post-quantum signature features are live on mainnet and a migration for existing holders is underway. ## Roadmap - **2023** (shipped): CKB team and Cryptape researchers implement a production-ready quantum-resistant lock script using SPHINCS+. Source: https://docs.nervos.org/docs/ckb-features/native-quantum-resistance - **August 2024** (shipped): NIST approves SPHINCS+ as SLH-DSA under FIPS 205, giving the deployed scheme a finalised standard. Source: https://csrc.nist.gov/pubs/fips/205/final - **2025** (shipped): The CKB team begins deploying the SPHINCS+ lock script on CKB mainnet, after a security audit by ScaleBit. Source: https://docs.nervos.org/docs/ckb-features/native-quantum-resistance - **February 2026** (shipped): The Quantum Purse desktop wallet ships, giving non-technical holders a route to SPHINCS+-locked funds. Source: https://github.com/nervosnetwork/quantum-resistant-lock-script ## Exposure CKB's cell model means an address commits to the hash of a lock script rather than to a public key directly, so a key is only revealed when a cell is spent. Unspent, never-spent holdings under secp256k1 are therefore not yet harvestable. This is materially better than account-model chains where every account's public key is on-chain from the first transaction, but it is the same structural position as Bitcoin: reuse and spending progressively expose the network, and the protection erodes rather than holds. ## Frequently asked questions ### Is Nervos CKB quantum-safe? Partly, and by user choice rather than by default. Nervos CKB does not hardcode a signature algorithm into its consensus rules. Signature verification runs as a Lock Script on a RISC-V virtual machine, so a post-quantum scheme can be added without changing the protocol. The CKB team used that property to build a SPHINCS+ lock script, audited by ScaleBit, and began deploying it on mainnet in 2025 alongside a wallet that uses it. A CKB holder can therefore move funds to a quantum-resistant address today, permissionlessly and without a fork. What CKB has not done is make that the default: ordinary CKB addresses still use secp256k1, which a sufficiently large quantum computer would break, and the large majority of supply still sits under those classical locks. ### Is Nervos CKB quantum-safe? It can be, if a holder chooses it. CKB has an audited SPHINCS+ lock script deployed on mainnet, so funds moved to a SPHINCS+ address are protected by a NIST-standardised post-quantum signature today. Funds left in ordinary CKB addresses use secp256k1 and remain quantum-vulnerable. ### Why does CKB not need a hard fork to add post-quantum signatures? Because CKB does not hardcode a signature algorithm in its consensus rules. Signature verification is implemented as a Lock Script running on a RISC-V virtual machine, so a new cryptographic scheme is deployed as a script on-chain rather than as a protocol change. Users adopt it by creating addresses that reference the new script's code hash. ### Has the SPHINCS+ lock script been audited? Yes. The Nervos documentation states the quantum-resistant lock script completed a security audit conducted by ScaleBit, and the implementation is open source in the nervosnetwork/quantum-resistant-lock-script repository, so the audit claim and the code can both be checked independently. ### How much CKB is actually protected by SPHINCS+? A small share. Deployment began in 2025 and the wallet supporting it shipped in 2026, so the overwhelming majority of CKB supply still sits under secp256k1 locks. Availability is not adoption, and this index scores CKB's signature dimension at 6 rather than higher for exactly that reason. ## What this rating means if you hold Nervos Plain-language guidance from the same publication, with no product recommendation attached. - [Is my crypto safe from quantum computers?](https://hardyindex.com/guides/is-my-crypto-safe-from-quantum-computers.md) - [How to protect your crypto from quantum computers](https://hardyindex.com/guides/how-to-protect-crypto-from-quantum-computers.md) - [All guides](https://hardyindex.com/guides.md) Nothing on this profile is sponsored and nothing on it is an affiliate link. See https://hardyindex.com/how-we-make-money.md. ## Sources 1. [Native Quantum Resistance](https://docs.nervos.org/docs/ckb-features/native-quantum-resistance): Nervos CKB documentation (primary, checked 11 August 2026) 2. [quantum-resistant-lock-script](https://github.com/nervosnetwork/quantum-resistant-lock-script): Nervos Network (GitHub) (primary, checked 11 August 2026) 3. [FIPS 205: Stateless Hash-Based Digital Signature Standard (SLH-DSA)](https://csrc.nist.gov/pubs/fips/205/final): NIST (primary, checked 11 August 2026) --- Methodology: https://hardyindex.com/methodology (v1.1). Cite as: The Hardy Index, "Nervos CKB", https://hardyindex.com/chains/nervos-ckb, as of 11 August 2026.