The Stellar Development Foundation released a Quantum Preparedness Plan this week, laying out a phased roadmap to migrate the entire network to quantum-safe cryptography by the end of 2027. The initiative tackles two core risks: validator signatures that could destabilize consensus if breached, and account takeover where a quantum machine derives a private key from a public key. Dormant accounts pose a particular challenge, so the Foundation is asking the community for input on handling inactive accounts and whether recovery mechanisms are possible.
Why the clock is ticking
Shor's algorithm can break the elliptic curve cryptography (ECC) that Stellar — and most blockchains — relies on. Scientists at INRIA have reduced the number of logical qubits needed to break 256-bit elliptic curves, making the threat more concrete. The US National Institute of Standards and Technology (NIST) revised its risk window for a quantum threat to 2029 or earlier. Google is targeting post-quantum readiness by 2029. The timing means Stellar needs to move fast.
Three stages, one deadline
The rollout starts this year: 2026 brings post-quantum signature verification — specifically ML-DSA-44 and ML-DSA-65 — to Soroban smart contracts. In 2027, a Core Advancement Proposal will bring quantum-safe signer types to classic accounts. A third stage that deprecates Ed25519 has no fixed date yet. That open question matters: Ed25519 is the current signing scheme, and turning it off is the real finish line.
The dormant account problem
Inactive accounts holding old-style keys could become the network's soft underbelly. The Foundation isn't ready to force a migration on those accounts — it wants community feedback first. The key question: should there be a recovery mechanism, or should the network simply freeze accounts that don't upgrade? Stellar's account addresses are separate from signing keys, which gives users flexibility to add or swap signers via set_options without changing their address, balance, or transaction history. That design helps, but it doesn't solve the dormancy issue alone.
What else remains vulnerable
The plan notes that zero-knowledge proof systems using pairing-based curves are still vulnerable to quantum attack. The Foundation says it will do further research and collaborate with ZK protocol teams. That's a longer-term problem, but for now the focus is on the core network.
