Sui has detailed its approach to introducing post-quantum cryptography without requiring users to undertake one of the most disruptive aspects of a blockchain security upgrade: transferring all assets to a new account.

According to the Sui Foundation's August 6 announcement, the network intends to support ML-DSA-65, standardized by NIST under FIPS 204, for standard accounts, and SLH-DSA-SHA2-128s, standardized under FIPS 205, for higher-value vaults built with Move smart contracts. Both schemes are designed to resist attacks from large-scale quantum computers that could eventually threaten the elliptic-curve signatures used across the cryptocurrency ecosystem today. NIST finalized FIPS 204 and 205 in August 2024 as the first U.S. government–approved post-quantum signature standards, culminating a multi-year public competition that began in 2016.

The threat model is well understood in cryptographic circles. Shor's algorithm, if run on a sufficiently large fault-tolerant quantum computer, could derive private keys from public keys that are publicly visible on every blockchain ledger. Because public keys are exposed at transaction time, an adversary could theoretically record signed transactions today and break the underlying keys once capable quantum hardware arrives—a concern often described as "harvest now, decrypt later." No publicly known quantum computer can currently perform this attack at the scale needed for production cryptographic keys, but researchers across academia and industry, including teams at IBM, Google, and national laboratories, continue to advance qubit counts and error correction.

The Account Can Stay Even When the Key Changes

Replacing the cryptography behind a blockchain account typically requires users to create a new address and transfer tokens, NFTs, and other assets. Applications and contracts tied to the old address may also require adjustment. For most blockchain networks, this means a post-quantum transition would require every holder to actively move funds—a coordination challenge that becomes harder as a chain's user base and deployed contract ecosystem grow.

Sui's existing Address Aliases system offers a path around this problem. An account can maintain a set of authorized aliases, allowing another signer to authenticate transactions on behalf of the original address. A new signer can be added to the authorized set and eventually become the sole signer permitted to approve transactions, while the original address continues to appear as the sender.

When ML-DSA accounts become available, Sui states that an existing account will be able to authorize a post-quantum signer while retaining the same address. This is particularly relevant for accounts already connected to smart contracts, identities, or other applications where changing an address would create substantially more work than simply transferring SUI tokens.

The recovery process is designed to remain familiar as well. An ML-DSA-65 key can be derived from a user's existing recovery phrase through a new derivation path, rather than requiring an entirely different backup method.

An authorized alias holds full authority over the account. Sui's documentation warns that adding one effectively grants that signer control over the assets owned by the address, meaning wallet software will need to make the migration process difficult to misuse or misunderstand.

Why Sui Is Using Two Different Quantum-Safe Systems

Sui is not relying on a single post-quantum design for all use cases.

ML-DSA-65 is lattice-based and intended for routine transaction signing. It corresponds to NIST security Category 3, offering a greater security margin than the smaller ML-DSA-44 configuration while remaining practical for frequent verification.

Sui also referenced the recent AI-assisted discovery of a weakness in HAWK, another post-quantum signature candidate. The finding did not compromise ML-DSA, but it demonstrated how rapidly automated cryptanalysis can challenge designs that have already undergone extensive human review.

For higher-value vaults, Sui plans to support SLH-DSA-SHA2-128s through Move smart contracts. This is a Category 1 configuration, below ML-DSA-65's Category 3 rating. Sui's rationale stems from its hash-based design, which offers an alternative to ML-DSA's lattice assumptions and reduces dependence on a single cryptographic foundation. A weakness discovered in one family would not automatically undermine the other, while the smart-contract implementation gives vault developers flexibility to replace the scheme later if necessary. The principle of deploying more than one unrelated cryptographic family is the same diversification logic that motivated NIST to standardize both lattice-based and hash-based signatures rather than relying on a single approach.

The tradeoff is signature size. An ML-DSA-65 signature is 3,309 bytes, compared with 64 bytes for a typical Ed25519 signature. Its public key is 1,952 bytes. The selected SLH-DSA-SHA2-128s configuration produces a 7,856-byte signature, which is considerably smaller than the 16–30 KB figures sometimes associated with SLH-DSA. Those larger figures apply to stronger SLH-DSA parameter sets, not the 128s configuration selected by Sui.

Larger signatures mean bigger transactions and more data moving across the network. Sui states that ML-DSA verification performance is close enough to Ed25519 that the per-signature network cost does not need to increase, although transaction size does increase. Further optimization is underway.

Users Do Not Need to Migrate Today

Quantum-safe vaults are targeted for Mainnet before the end of 2026. Native ML-DSA-65 accounts are expected on Testnet by year-end, followed by native Mainnet account authentication in the first quarter of 2027. Wallet, SDK, and command-line support are planned alongside the rollout. Most major Layer 1 blockchains have discussed post-quantum migration in general terms, but few have published concrete timelines with specific NIST-standardized algorithms and on-chain mechanisms, placing Sui among the earlier networks to commit to a detailed roadmap.

Independent audits and Testnet feedback remain underway, so these timelines could shift before the features reach production.

Existing accounts do not need to take any action at this time. The new authentication methods will be additive and opt-in rather than a forced network-wide migration.

The migration design also establishes a straightforward warning sign for potential scams. Sui's stated migration path does not require holders to send their assets to a newly supplied wallet address. Any unsolicited message claiming that funds must urgently be transferred elsewhere to become "quantum safe" would be inconsistent with the mechanism Sui has described.

No publicly known quantum computer can currently break the signatures protecting Sui accounts. The relevant question is whether the network can migrate its cryptography before that capability becomes practical. Sui's approach is to make the key replaceable without making the account disposable.

Methodology: This article references the Sui Foundation's August 6 announcement, official Sui Address Alias documentation, and NIST FIPS 204 and FIPS 205 specifications. Signature sizes and security categories were checked against the relevant NIST standards. Features already supported through Address Aliases are distinguished from post-quantum functionality that remains on Sui's development roadmap.

Disclaimer: This article is provided for informational and educational purposes only and does not constitute financial, investment, or security advice. Sui's post-quantum features remain under development, independent review, and testing, and implementation details or timelines may change before Mainnet release.