Aptos AIP-137: Introducing Optional Post-Quantum Signatures with SLH-DSA (FIPS 205)

Aptos is looking to bolster long-term security by proposing AIP-137, which would introduce post-quantum signatures at the account level as an optional feature, designed to run alongside current encryption without disrupting existing addresses. The plan addresses escalating concerns about quantum threats to classical cryptography as the blockchain ecosystem migrates toward resilient cryptographic primitives. Under the proposal, the network would adopt the hash-based SLH-DSA, a scheme recently standardized as FIPS 205, to provide quantum-resistant digital signatures. This approach enables gradual rollout, preserving backward compatibility while enabling institutions and developers to evaluate post-quantum readiness. If adopted, Aptos would join a broader industry shift toward quantum-safe infrastructure, potentially informing token cross-chain security and long-horizon risk management for custodians and validators.