--- title: Is Stellar quantum-safe? chain: Stellar ticker: XLM hardy_score: 41 rank: 9 of 23 tier: "3: Committed" url: "https://hardyindex.com/chains/stellar" updated: 2026-08-12 methodology_version: 1.1 --- # Is Stellar quantum-safe? **Hardy Score 41.0 / 100. Rank 9 of 23. Tier 3: Committed. As of 12 August 2026.** No, not today. Stellar accounts are secured by Ed25519, which a sufficiently large quantum computer would break. Stellar has published a Quantum Preparedness Plan, and its first stage during 2026 is to add post-quantum signature verification to Soroban, Stellar's smart contract environment, as native host functions supporting ML-DSA-44 and ML-DSA-65. The route to holder safety runs through Soroban's account abstraction layer: contract accounts can implement quantum-safe authentication without the protocol having to replace Ed25519 for everyone at once. That is a sound design, and it is also an opt-in one, so the pace of real protection will depend on adoption rather than on the upgrade alone. > This is a security-readiness assessment, not investment advice. ## Summary A published Quantum Preparedness Plan whose first stage adds ML-DSA verification to Soroban as native host functions, letting contract accounts authenticate with quantum-safe keys. ## Score breakdown | # | Dimension | Score | Weight | Contribution | |---:|---|---:|---:|---:| | 1 | Signature scheme | 0/10 | 30% | 0.0 | | 2 | Deployment stage | 5/10 | 25% | 12.5 | | 3 | NIST alignment | 8/10 | 15% | 12.0 | | 4 | Migration path | 7/10 | 15% | 10.5 | | 5 | Exposure | 2/10 | 10% | 2.0 | | 6 | Verification | 8/10 | 5% | 4.0 | | | **Hardy Score** | | | **41.0** | ### 1. Signature scheme: 0/10 Stellar accounts sign with Ed25519 and no post-quantum signature protects live XLM on mainnet. The planned ML-DSA support is verification inside Soroban rather than a deployed account signature scheme. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan ### 2. Deployment stage: 5/10 Tier 3: Committed. A published, staged preparedness plan with named schemes and a 2026 first stage, and nothing post-quantum live on mainnet at the time of writing. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan ### 3. NIST alignment: 8/10 The plan names ML-DSA-44 and ML-DSA-65, both parameter sets of the finalised FIPS 204 standard, rather than referring to post-quantum cryptography in the abstract. Committing to specific parameter sets of a final standard is a strong signal. Source: https://csrc.nist.gov/pubs/fips/204/final ### 4. Migration path: 7/10 Soroban's account abstraction gives Stellar a credible route: contract accounts can adopt quantum-safe authentication without a protocol-wide signature replacement or a contentious fork. The deduction is that this makes protection opt-in, so classic Ed25519 accounts are not carried across by the upgrade itself. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan ### 5. Exposure: 2/10 A Stellar account ID is a direct encoding of the Ed25519 public key, so the key is readable from the address whether or not the account has ever transacted. Effectively all classical XLM is harvestable today. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan ### 6. Verification: 8/10 The plan is published by the Stellar Development Foundation under its own name with named algorithms and staged scope, and the protocol and Soroban are open source, so the first stage can be checked against the code as it lands. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan ## Signature scheme - **On mainnet today:** Ed25519 for all classic accounts - **Post-quantum scheme:** ML-DSA-44 and ML-DSA-65 verification as native Soroban host functions, with quantum-safe authentication through contract accounts - **NIST standard:** FIPS 204 (ML-DSA), finalised August 2024 - **Readiness tier:** Tier 3: Committed. A funded roadmap with public dates and active research exists, but no post-quantum signature is live on mainnet. ## Roadmap - **Stage 1, during 2026** (in-progress): Add post-quantum signature verification to Soroban as native host functions supporting ML-DSA-44 and ML-DSA-65, with contract accounts able to implement quantum-safe authentication through account abstraction. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan - **Later stages, no date published** (planned): Broader protocol-level quantum preparedness beyond Soroban contract accounts. No dated schedule was found at the time of writing. Source: https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan ## Exposure A Stellar account ID, the string beginning with G that users share, is a direct encoding of the account's Ed25519 public key. There is no hashing step, so the key is known to anyone who knows the address, whether or not the account has ever signed a transaction. This puts Stellar in the same structural position as Algorand, Solana and Polkadot: every classical balance is available for harvest-now-decrypt-later collection today, and never transacting does not help. Contract accounts on Soroban are where the planned quantum-safe authentication will live. ## Frequently asked questions ### Is Stellar quantum-safe? No, not today. Stellar accounts are secured by Ed25519, which a sufficiently large quantum computer would break. Stellar has published a Quantum Preparedness Plan, and its first stage during 2026 is to add post-quantum signature verification to Soroban, Stellar's smart contract environment, as native host functions supporting ML-DSA-44 and ML-DSA-65. The route to holder safety runs through Soroban's account abstraction layer: contract accounts can implement quantum-safe authentication without the protocol having to replace Ed25519 for everyone at once. That is a sound design, and it is also an opt-in one, so the pace of real protection will depend on adoption rather than on the upgrade alone. ### Is Stellar quantum-safe? No. Stellar accounts use Ed25519, which a sufficiently large quantum computer would break. Stellar has published a Quantum Preparedness Plan whose first stage adds ML-DSA verification to Soroban during 2026, but no post-quantum signature protects XLM on mainnet today. ### What does Stellar's Quantum Preparedness Plan actually do first? Stage 1 adds post-quantum signature verification to Soroban, Stellar's smart contract environment, as native host functions supporting ML-DSA-44 and ML-DSA-65. Contract accounts can then implement quantum-safe authentication through Soroban's account abstraction layer, without the protocol replacing Ed25519 for every classic account at once. ### Does the Soroban approach protect ordinary Stellar accounts? Not automatically. Building quantum-safe authentication into contract accounts means holders have to move to one to benefit. It avoids a contentious protocol-wide change, which is a real advantage, but it makes protection opt-in rather than universal, and adoption is what determines how much value is actually covered. ### Why is Stellar's exposure score so low? Because a Stellar account ID encodes the public key directly rather than a hash of it. On chains where the address is a key hash, a funded account that has never spent keeps its key private. On Stellar the key is readable from the address, so all classical XLM is exposed to collection today. ## What this rating means if you hold Stellar Plain-language guidance from the same publication, with no product recommendation attached. - [Is my crypto safe from quantum computers?](https://hardyindex.com/guides/is-my-crypto-safe-from-quantum-computers.md) - [How to protect your crypto from quantum computers](https://hardyindex.com/guides/how-to-protect-crypto-from-quantum-computers.md) - [All guides](https://hardyindex.com/guides.md) Nothing on this profile is sponsored and nothing on it is an affiliate link. See https://hardyindex.com/how-we-make-money.md. ## Sources 1. [Introducing the Quantum Preparedness Plan](https://stellar.org/blog/foundation-news/introducing-the-quantum-preparedness-plan): Stellar Development Foundation (primary, checked 12 August 2026) 2. [FIPS 204: Module-Lattice-Based Digital Signature Standard (ML-DSA)](https://csrc.nist.gov/pubs/fips/204/final): NIST (primary, checked 12 August 2026) 3. [Safeguarding cryptocurrency by disclosing quantum vulnerabilities responsibly](https://research.google/blog/safeguarding-cryptocurrency-by-disclosing-quantum-vulnerabilities-responsibly/): Google Research (primary, checked 12 August 2026) --- Methodology: https://hardyindex.com/methodology (v1.1). Cite as: The Hardy Index, "Stellar", https://hardyindex.com/chains/stellar, as of 12 August 2026.