Sui has outlined a roadmap for introducing post-quantum cryptography to its blockchain, writing in a blog post on the strategy that public blockchains face a unique security challenge because users’ public keys become permanently visible after their first transaction. Unlike most traditional computer systems, where an attacker must first breach a system to obtain a public key, blockchain addresses expose that information by design, allowing adversaries to collect keys today and potentially exploit them once large-scale quantum computers become available.
The concern centers on Shor’s algorithm, the quantum algorithm capable of breaking the elliptic-curve cryptography that secures most blockchain wallets and much of today’s internet. Although fault-tolerant quantum computers capable of running such attacks do not yet exist, Sui notes that attackers can already collect exposed public keys in anticipation of future advances. The company cites Google’s March 2026 estimate that recovering a private key from an exposed public key could eventually take only minutes on a fault-tolerant quantum computer with fewer than 500,000 physical qubits.
At the same time, government timelines for adopting quantum-resistant cryptography continue to accelerate, according to the post. While the National Institute of Standards and Technology (NIST) previously targeted the early-to-mid 2030s for retiring current public-key cryptography, Executive Order 14412, signed in June 2026, requires U.S. federal agencies to transition sensitive systems to post-quantum key establishment by the end of 2030 and digital signatures by the end of 2031.
Sui says its blockchain architecture was designed with “cryptographic agility,” allowing new signature schemes to be added without altering the network’s consensus mechanism or requiring a disruptive migration. Instead of rebuilding the protocol, the company describes the transition as a routine feature update.
Rather than relying on a single post-quantum algorithm, Sui plans to deploy two standardized signature schemes designed for different use cases.
For ordinary user accounts, the blockchain will adopt ML-DSA-65, the lattice-based digital signature algorithm standardized by NIST in FIPS 204. Sui selected the higher-security Level 3 parameter set rather than the smaller Level 1 version, citing the growing pace of cryptanalysis, including a July 2026 incident in which researchers used artificial intelligence to identify weaknesses in another post-quantum signature candidate, HAWK. Although that finding did not affect ML-DSA, Sui said it reinforced the value of choosing more conservative security margins. The same parameter set has also been adopted by major technology providers including Chrome, Cloudflare, Amazon Web Services and Android.
For high-value smart contract vaults, Sui will implement SLH-DSA-SHA2-128s, the hash-based signature scheme standardized in FIPS 205. Rather than embedding this directly into the blockchain protocol, Sui will implement it within Move smart contracts. The company says that approach allows vaults to evolve alongside future post-quantum standards without requiring protocol upgrades while also providing diversity by relying on a different mathematical foundation than lattice-based signatures.
A major focus of the rollout is minimizing disruption for users. New post-quantum private keys will continue to use 32-byte seeds derived from existing wallet recovery phrases through a new derivation path, allowing wallets to back up and restore accounts much as they do today. Existing accounts will also be able to migrate to post-quantum authorization without transferring assets by updating their authorization keys through Sui’s existing address alias system, preserving both wallet addresses and account balances.
The principal tradeoff is larger signatures and public keys, which increase transaction size compared with today’s Ed25519 cryptography. Sui says benchmarking shows that signature verification performance remains close enough to current levels that per-signature network costs should remain largely unchanged, while existing transaction limits and programmable transaction features can accommodate the larger data sizes.
The implementation is already built and undergoing benchmarking and independent security audits. Sui plans to introduce quantum-safe vaults on Mainnet later this year, followed by native ML-DSA-65 accounts on Testnet by the end of 2026 and Mainnet account authentication in the first quarter of 2027. The rollout will be gradual and optional, following the same deployment model previously used for features such as zkLogin and passkeys, allowing existing applications and accounts to continue operating without modification.
