Sui is advancing plans to integrate post-quantum cryptographic tools, aiming to shield user accounts from potential future threats posed by quantum computers. The Layer 1 blockchain will incorporate two signature methods standardized by the National Institute of Standards and Technology (NIST). These additions allow optional upgrades to quantum-resistant keys while preserving existing recovery phrases and addresses. Quantum computers capable of running Shor’s algorithm could eventually compromise the elliptic-curve cryptography that underpins most blockchain accounts today. On public ledgers, public keys become permanently visible once an account initiates a transaction, creating opportunities for “harvest-now, decrypt-later” collection of data. Recent estimates suggest a sufficiently advanced quantum system might recover private keys from exposed public ones relatively quickly. Regulatory timelines are also tightening, with moves to phase out classical algorithms in sensitive systems in the coming years. Sui’s architecture emphasizes cryptographic flexibility, enabling new signature schemes to be introduced as standard protocol features rather than requiring major overhauls to consensus or network state. This approach supports a smoother transition compared to chains that would need broader migrations. The network will deploy two complementary schemes tailored to different use cases. For routine accounts and everyday transactions, ML-DSA-65 (aligned with NIST’s FIPS 204) will function as a native protocol-level option at security Level 3. This parameter set was selected over lighter alternatives to provide additional margin, informed by recent demonstrations of advances in analyzing related candidates. Similar Level 3 choices appear in other systems securing substantial web traffic and hardware key services. For high-value assets held in vaults, the hash-based SLH-DSA-SHA2-128s (FIPS 205) will operate inside Move smart contracts. This placement keeps the more mature hash-based approach flexible and avoids locking the core protocol to one standard, allowing compatibility with evolving industry practices—particularly useful given Sui’s cross-chain connections. Relying on distinct mathematical foundations (lattice-based versus