--- title: Is Sui quantum-safe? chain: Sui ticker: SUI hardy_score: 45.5 rank: 7 of 23 tier: "3: Committed" url: "https://hardyindex.com/chains/sui" updated: 2026-08-12 methodology_version: 1.1 --- # Is Sui quantum-safe? **Hardy Score 45.5 / 100. Rank 7 of 23. Tier 3: Committed. As of 12 August 2026.** Not yet, but Sui has one of the better-designed transitions in this index. Sui accounts sign with Ed25519 today, which a sufficiently large quantum computer would break. In August 2026 Sui committed to adding two post-quantum schemes that are already finalised NIST standards: ML-DSA-65 under FIPS 204 as a native protocol signature scheme for everyday accounts, and SLH-DSA-SHA2-128s under FIPS 205 for smart contract vaults. The detail that matters most for holders is that the new keys are derived from the recovery phrase people already hold, so accounts can move to quantum-safe keys without changing their addresses. Quantum-safe vaults are targeted for mainnet during 2026, native ML-DSA-65 accounts for testnet by the end of 2026, and native account authentication on mainnet in the first quarter of 2027. > This is a security-readiness assessment, not investment advice. ## Summary Committed in August 2026 to two finalised NIST schemes, with a migration path that lets existing accounts move to quantum-safe keys without changing their addresses. ## Score breakdown | # | Dimension | Score | Weight | Contribution | |---:|---|---:|---:|---:| | 1 | Signature scheme | 0/10 | 30% | 0.0 | | 2 | Deployment stage | 5/10 | 25% | 12.5 | | 3 | NIST alignment | 9/10 | 15% | 13.5 | | 4 | Migration path | 9/10 | 15% | 13.5 | | 5 | Exposure | 2/10 | 10% | 2.0 | | 6 | Verification | 8/10 | 5% | 4.0 | | | **Hardy Score** | | | **45.5** | ### 1. Signature scheme: 0/10 Sui accounts are signed with Ed25519 today and nothing post-quantum protects live funds on mainnet. The post-quantum schemes are committed and dated but not yet deployed. Source: https://www.sui.io/blog/making-sui-quantum-ready ### 2. Deployment stage: 5/10 Tier 3: Committed. Two named standards, a phased schedule with public dates running to the first quarter of 2027, and active engineering, with nothing post-quantum live on mainnet yet. Source: https://www.sui.io/blog/making-sui-quantum-ready ### 3. NIST alignment: 9/10 Both selected schemes are final NIST standards rather than candidates: ML-DSA-65 under FIPS 204 for accounts and SLH-DSA-SHA2-128s under FIPS 205 for contract vaults. Committing to two finalised standards is stronger than naming a scheme still awaiting publication. Source: https://csrc.nist.gov/pubs/fips/204/final ### 4. Migration path: 9/10 The strongest migration design among the committed chains. Post-quantum keys are derived from the recovery phrase holders already have, so accounts can move to quantum-safe authentication without changing addresses. That removes the coordination problem that makes migration hard elsewhere. Source: https://www.sui.io/blog/making-sui-quantum-ready ### 5. Exposure: 2/10 Sui uses an account model in which the public key is published when an account first transacts, so effectively all economically active supply has an exposed key today and is harvestable against a future quantum computer. Source: https://www.sui.io/blog/making-sui-quantum-ready ### 6. Verification: 8/10 The commitment was published by Sui under its own name with named schemes and dated milestones, and the protocol is open source, so each milestone is checkable against the calendar as it passes. Source: https://github.com/MystenLabs/sui ## Signature scheme - **On mainnet today:** Ed25519 for accounts, with multi-scheme support - **Post-quantum scheme:** ML-DSA-65 for native accounts; SLH-DSA-SHA2-128s for smart contract vaults - **NIST standard:** FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA), both finalised August 2024 - **Readiness tier:** Tier 3: Committed. A funded roadmap with public dates and active research exists, but no post-quantum signature is live on mainnet. ## Roadmap - **6 August 2026** (shipped): Sui commits to adding ML-DSA-65 and SLH-DSA-SHA2-128s, with post-quantum keys derived from existing recovery phrases so addresses do not change. Source: https://github.com/MystenLabs/sui - **During 2026** (planned): Quantum-safe smart contract vaults using SLH-DSA targeted for mainnet. Source: https://www.sui.io/blog/making-sui-quantum-ready - **End of 2026** (planned): Native ML-DSA-65 accounts on testnet. Source: https://www.sui.io/blog/making-sui-quantum-ready - **Q1 2027** (planned): Native post-quantum account authentication on mainnet. Source: https://www.sui.io/blog/making-sui-quantum-ready ## Exposure Sui is an account-model chain, so a public key becomes visible on-chain once an account transacts. In practice that means effectively all economically active SUI sits behind an exposed Ed25519 key today and can be recorded now for a future quantum attack. Sui's structural advantage is not in exposure but in recovery: because keys are derived deterministically from a seed phrase, a holder can adopt a post-quantum key without abandoning their address, which is the step most chains have not solved. ## Frequently asked questions ### Is Sui quantum-safe? Not yet, but Sui has one of the better-designed transitions in this index. Sui accounts sign with Ed25519 today, which a sufficiently large quantum computer would break. In August 2026 Sui committed to adding two post-quantum schemes that are already finalised NIST standards: ML-DSA-65 under FIPS 204 as a native protocol signature scheme for everyday accounts, and SLH-DSA-SHA2-128s under FIPS 205 for smart contract vaults. The detail that matters most for holders is that the new keys are derived from the recovery phrase people already hold, so accounts can move to quantum-safe keys without changing their addresses. Quantum-safe vaults are targeted for mainnet during 2026, native ML-DSA-65 accounts for testnet by the end of 2026, and native account authentication on mainnet in the first quarter of 2027. ### Is Sui quantum-safe? Not yet. Sui accounts use Ed25519, which a sufficiently large quantum computer would break. Sui committed in August 2026 to adding two finalised NIST post-quantum schemes, with native quantum-safe accounts targeted for mainnet in the first quarter of 2027. ### Will Sui holders have to change their address? No, according to Sui's published plan. The post-quantum keys are derived from the same recovery phrase holders already have, which lets an account move to quantum-safe authentication while keeping its existing address. That is unusual and is the main reason Sui scores 9 on migration in this index. ### Which post-quantum schemes is Sui adopting? Two, for two different jobs. ML-DSA-65, standardised as FIPS 204, becomes a native protocol signature scheme for everyday accounts. SLH-DSA-SHA2-128s, standardised as FIPS 205, is used for smart contract vaults. Both are final NIST standards rather than candidates awaiting publication. ### Why does Sui still score below 50 if its plan is strong? Because the signature dimension carries 30 per cent of the score and measures what protects funds on mainnet today, which for Sui is still Ed25519. A plan, however well designed, cannot earn those points until it ships. Sui's score reflects a strong roadmap attached to an entirely classical present. ## What this rating means if you hold Sui 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. [Making Sui Quantum Ready](https://www.sui.io/blog/making-sui-quantum-ready): Sui Foundation (primary, checked 12 August 2026) 2. [Sui reference implementation](https://github.com/MystenLabs/sui): Mysten Labs (GitHub) (primary, checked 12 August 2026) 3. [FIPS 204: Module-Lattice-Based Digital Signature Standard (ML-DSA)](https://csrc.nist.gov/pubs/fips/204/final): NIST (primary, checked 12 August 2026) 4. [FIPS 205: Stateless Hash-Based Digital Signature Standard (SLH-DSA)](https://csrc.nist.gov/pubs/fips/205/final): NIST (primary, checked 12 August 2026) --- Methodology: https://hardyindex.com/methodology (v1.1). Cite as: The Hardy Index, "Sui", https://hardyindex.com/chains/sui, as of 12 August 2026.