The two schemes are ML-DSA-65 (standardized as FIPS 204) and SLH-DSA-SHA2-128s (FIPS 205), both finalized by the U.S. National Institute of Standards and Technology in August 2024. Sui is deploying them on separate tracks matched to different risk profiles: ML-DSA-65 will secure everyday accounts and transactions, while SLH-DSA-SHA2-128s will protect high-value smart contract vaults. The announcement comes as Google Quantum AI's March 2026 estimates put private-key recovery via Shor's algorithm within reach of machines operating at fewer than 500,000 physical qubits, with recovery achievable in minutes. Google separately projects that machines capable of breaking blockchain cryptography may exist by 2029.

Why the Threat Is Not Hypothetical

The core vulnerability on public blockchains is structural. Every time an account sends a transaction, its public key is permanently written to the chain. That exposed key is enough for a quantum computer running Shor's algorithm to reconstruct the private key and forge signatures. Researchers call this a "harvest-now, forge-later" attack: adversaries collect public keys today and hold them until quantum hardware is capable enough to crack them. According to a circulating but not yet peer-reviewed analysis from Qubitchain.io, published in June 2026, between 35 and 50 percent of a token's circulating supply could sit in wallets already exposed to this approach. For Bitcoin specifically, roughly 6.9 million BTC, representing approximately one-third of Bitcoin's total supply, sit in wallets where the public key is on-chain and visible.

The urgency sharpened further in late July 2026 when Anthropic disclosed that its Claude "Mythos Preview" AI model had found a critical flaw in HAWK, a separate post-quantum signature candidate under NIST review. The model identified a previously unused symmetry in HAWK's lattice structure, specifically within the Lattice Isomorphism Problem underpinning the scheme, in approximately 60 hours, reducing the effective security of the scheme from roughly 2⁶⁴ to 2³⁸ operations. Human cryptographers had reviewed HAWK for two full years without catching it. The HAWK team subsequently withdrew the scheme from NIST consideration. Sui cited that episode directly as justification for implementing ML-DSA-65 at Level 3, a more conservative security tier, rather than the lower-cost Level 1 option.

How the Migration Works

Sui says existing users will not need to generate a new recovery phrase or move their funds to a new address. ML-DSA-65 private keys use a 32-byte seed derived from the same recovery phrase through a new derivation path, keeping key storage requirements identical to what wallets already manage. Existing accounts can switch to quantum-safe authorization through a feature called "address aliases," already live on Sui Mainnet, which allows an account to update its authorization key while keeping the same address and all of its assets in place. Migration is opt-in.

"The hardest part of any cryptographic migration is not the new algorithm," the Sui Foundation wrote in its announcement. "The problem is that everyone is already using the old one." The foundation added that "existing accounts have a path that does not involve moving funds. No forced migration, no expensive transfer of everything an account holds."

SLH-DSA-SHA2-128s is handled inside Move contracts rather than the protocol core, giving the protocol flexibility without requiring core upgrades and allowing quantum-safe smart contract vaults to reach Mainnet sooner than the broader account-level migration.

The planned rollout runs in three stages: quantum-safe smart contract vaults targeting Mainnet in Q3 2026 (within the current quarter, approximately seven weeks from publication), native ML-DSA-65 accounts on Testnet by the end of 2026, and ML-DSA-65 accounts on Mainnet by Q1 2027. ML-DSA-65 verification costs are comparable to the existing Ed25519 scheme Sui currently uses, meaning ordinary transactions should not become materially more expensive.

What This Means for Emerging Markets

The upgrade carries particular weight for users in Africa, where Sui has become foundational infrastructure for stablecoin payments over the past year. In May 2026, Nigerian fintech company Paga announced an integration with Sui to deploy USDsui, a USD-pegged stablecoin backed by Treasury-grade assets. Paga processed more than $11 billion across 169 million payments in 2025, and the integration targets high-yield accounts, cross-border remittances, and tokenized real-world assets. Nigeria accounts for roughly 60 percent of Africa's stablecoin activity, and Sub-Saharan Africa received approximately $205 billion in on-chain value during the 2024 to 2025 cycle, up 52 percent year over year.

For users in markets where stablecoins function as primary savings and payment tools rather than speculative instruments, the design choice to avoid forced fund migration matters. Wallets in Nigeria, Ghana, and across East Africa do not need to be rebuilt or re-seeded to become quantum-safe. Kenya's Web3 developer community, 86 percent of which is under 28 years old, also stands to benefit from building on a platform with a documented post-quantum roadmap as local VASP regulation matures under the country's VASP Act 2025.

South Asia represents another significant region where Sui's post-quantum roadmap carries practical weight. India ranks among the top five global crypto markets, and its developer community is deeply active in Solana and other EdDSA ecosystems, making Sui's post-quantum technical paper directly applicable to infrastructure and tooling decisions. In Pakistan and Bangladesh, diaspora remittance corridors depend heavily on stablecoin rails, and the harvest-now, forge-later threat is particularly acute for long-term stablecoin savers holding funds in currency-volatile markets. For these users, the absence of forced migration is not a convenience feature but a practical necessity.

Competitive Context

No other top-20 blockchain has deployed post-quantum signature support at the protocol level as of August 2026. Ethereum has announced a quantum-safety target of 2029. Algorand has published plans but not shipped them. NIST has mandated deprecation of classical cryptographic algorithms by 2030 and full phase-out by 2035, a deadline that regulated market compliance frameworks are beginning to formalize as a concrete consideration for institutional fintech builders. Sui's technical paper on the migration, "Post-Quantum Readiness in EdDSA Chains," was first presented as a poster at ACM CCS 2025 before receiving conditional acceptance at Financial Cryptography 2026, one of 45 papers accepted from a pool of 246 submissions. The paper's findings are directly applicable to other EdDSA and RFC 8032 chains, including Solana and Near Protocol, making its implications relevant well beyond the Sui ecosystem.