Hardy Index Quantum readiness, rated and tracked

Chain profile

Terra Classic

LUNC Exposed

Terra Classic accounts sign with secp256k1 and validators with Ed25519 on a Cosmos SDK v0.53 chain; a core contributor's pre-formal post-quantum roadmap names ML-DSA, but it has not reached governance.

Is Terra Classic quantum-safe?

No. Terra Classic is the original Terra chain, columbus-5, kept running by its community since the May 2022 collapse. LUNC accounts sign with ECDSA on secp256k1, and validators sign consensus votes with Ed25519, which the chain's consensus parameters make the one accepted validator key type. A sufficiently large quantum computer breaks both. The node, classic-terra/core, runs Cosmos SDK v0.53.6, which has no post-quantum key type, and the v4.1.1 upgrade, which took effect at height 31,010,600 on 26 October 2026, kept the same SDK. In May 2026 a contributor to the node software published a Post-Quantum Roadmap RFC on the community forum that selects ML-DSA for validator consensus and a hybrid ML-DSA path for wallets, but the author described it as a non-binding, pre-formal discussion, not a governance proposal, and the governance step the author said would follow has not been submitted. LUNC also circulates as bridged tokens on Ethereum, BNB Smart Chain and Solana, where those chains' signatures protect it.

Where we are making a judgement call Three judgement calls. The first is the tier. The Post-Quantum Roadmap RFC was written by fragwuerdig, a contributor to classic-terra/core who published its v4.0.1-patch.3 release, so it comes from someone working on the chain's node rather than an outsider, and it names a scheme and a phased route. A reader who counts it as documented post-quantum work by people with authority over the chain would place Terra Classic in Tier 4, with a deployment score of 2, raising the Hardy Score from 14.5 to 17.0. We do not, because the Tier 4 floor asks for a formal improvement proposal or a public research programme, and the author said the post is not a governance proposal and not the formal RFC window; the governance proposal the author said would follow the discussion round, which closed on 5 June 2026, had not been submitted by 23 October 2026. Terra Classic's authority is its on-chain governance, and the RFC has not reached it. The second is the NIST score, which credits that same draft for naming ML-DSA for the chain's own signatures. A reader who credits only work with formal standing would score NIST alignment 0, and the Hardy Score would be 10.0. The third is migration and the upstream framework. The score of 3 credits the same draft as an acknowledgement of the problem, on top of the chain's record of governance-approved software upgrades; a reader who credits the upgrade record alone would score 2, a Hardy Score of 13.0. The ML-DSA keys in Cosmos SDK v0.55 are not credited, because Terra Classic runs SDK v0.53.6 and no one with authority over it has proposed moving to v0.55; a reader who credits them as the Cosmos Hub profile does might score NIST alignment 5, migration 5 and verification 3 and place the chain in Tier 4, a Hardy Score of 23.5. On dating: the Terra ledger dates from the Columbus mainnet of 2019, and this profile dates the chain now running, columbus-5, whose genesis file records a genesis time of 30 September 2021. Separately, Terra Classic is rated as it runs today; if it stops producing blocks of its own, it leaves the index.

At a glance

On mainnet today

ECDSA on secp256k1 for accounts; Ed25519 for validator consensus keys

Post-quantum scheme

None deployed. A pre-formal RFC by a node contributor selects ML-DSA for consensus and a hybrid ML-DSA path for wallets; it has not been put to governance.

NIST standard

FIPS 204 (ML-DSA) named in a pre-formal draft; none adopted

Readiness tier

Tier 5: Exposed. The signatures securing funds on mainnet today are quantum-vulnerable, and no public post-quantum plan, proposal or research programme addressing them could be found.

Cryptography in use

  • Account signatures ECDSA on secp256k1 Mainnet, default Read from a public node on 23 October 2026: every signer in the first 100 of the 13,071 mainnet transactions between heights 30,962,000 and 30,962,700 carries a secp256k1 public key, and none carries another key type. secp256k1 is the Cosmos SDK default account key. Read on-chain
  • Validator consensus Ed25519 Mainnet, mandatory The consensus parameters accept ed25519 as the one validator key type. Read on-chain
  • Validator consensus ML-DSA Proposed Selected as the consensus target profile in a pre-formal RFC posted for informal discussion in May 2026. No parameter set is named and no code exists. Specification or proposal
  • Account signatures ML-DSA Proposed The same RFC proposes a hybrid path in which classical and ML-DSA transaction signatures are accepted side by side. Its details are listed as open decisions. Specification or proposal

A role not listed is not evidenced either way. Every scheme, and which other chains share it, is in the cryptography registry.

Score breakdown

Each dimension scored 0 to 10. The weight beside it is its share of the total score.
Signature scheme 0 30% Deployment stage 1 25% NIST alignment 3 15% Migration path 3 15% Exposure 2 10% Verification 2 5%
Show the weighted arithmetic and the sourced note for each dimension
No. Dimension Score Weight Contribution
1 Signature scheme 0 30% 0.0
2 Deployment stage 1 25% 2.5
3 NIST alignment 3 15% 4.5
4 Migration path 3 15% 4.5
5 Exposure 2 10% 2.0
6 Verification 2 5% 1.0
Hardy Score 14.5

1 Signature scheme 0/10, weighted 30%

Band 0: Classical signatures only on mainnet, with nothing post-quantum protecting live funds. Short-lived devnets and one-off benchmarks sit here: they demonstrate research rather than something a user can hold keys on.

LUNC accounts sign with ECDSA on secp256k1: every signer in the first 100 of 13,071 mainnet transactions between heights 30,962,000 and 30,962,700, read from a public node on 23 October 2026, carried a secp256k1 key. Validators sign with Ed25519, the one key type the consensus parameters accept. Nothing post-quantum protects LUNC on mainnet. source

2 Deployment stage 1/10, weighted 25%

Band 1: Tier 5: Exposed.

Tier 5: Exposed. The signatures securing LUNC are quantum-vulnerable, and the post-quantum document with standing is a roadmap RFC by a classic-terra/core contributor that its author posted as an informal, non-binding discussion, stating it is not a governance proposal. The governance proposal the author said would open the formal RFC has not been submitted. See the caveat below on why this is a judgement call. A community post of 23 July 2026, "LUNC Must Become Quantum Resistant", carries no authority over the chain. source

3 NIST alignment 3/10, weighted 15%

Band 3 to 5: NIST schemes are referenced as candidates without a committed selection, or the work is bespoke research.

The pre-formal RFC selects ML-DSA, from the final FIPS 204, as the target for the consensus path and as the post-quantum half of a hybrid path for wallet and transaction signatures. It names no parameter set, and the decision log calls it a target profile in a document that is not yet in the formal RFC process. source

Placement in the band The bottom of the band rather than a 4 or a 5: the document is a pre-formal draft with no governance standing, and it names the scheme without a parameter set. Above a 2, because a final NIST standard is named for the chain's own fund-protecting signatures by a contributor to its node software.

4 Migration path 3/10, weighted 15%

Band 3 to 5: Migration is acknowledged as a problem with no agreed mechanism, or the mechanism is contested.

No migration plan is adopted. Terra Classic has a working route for protocol change: governance has passed a run of software upgrades, including v4.0.0, which moved the chain to Cosmos SDK v0.53, in April 2026, and v4.1.1, which took effect at height 31,010,600 on 26 October 2026. The RFC sketches a hybrid ML-DSA path for wallets and a validator key binding before a consensus cutover, and it comes from a contributor to the chain's node, but it is a draft, and no mechanism for holders exists in the node. source

Placement in the band The floor of the band rather than a 2: the RFC from a classic-terra/core contributor acknowledges the problem and sketches a route, as the Sonic and Kaspa profiles credit, and governance ships coordinated upgrades routinely. Not a 4, because the route is a pre-formal draft that has not been put to governance, and no mechanism exists in the code.

5 Exposure 2/10, weighted 10%

Band 0 to 2: Public keys are exposed for effectively all accounts, or a large, measured share of total supply sits in exposed addresses.

A Terra Classic address is a Bech32 hash of the secp256k1 public key, so an account that has never signed keeps its key off the chain. The key is recorded with the account's opening transaction, and staking LUNC needs a signed delegation, so actively held LUNC sits behind a revealed key. Validator consensus keys are published by design. No measurement of the exposed share has been published. source

Placement in the band The top of the band rather than a 3: the address structure is the same as on other Cosmos SDK key-hash chains, where any send or delegation reveals the key. It is not a 0 or a 1 because never-used addresses do keep their keys hidden.

6 Verification 2/10, weighted 5%

Band 0 to 2: No post-quantum component exists, or the claims rest on marketing.

No post-quantum component protects Terra Classic, so there is nothing to verify: the RFC is a design document with no code, and neither v4.0.1-patch.3 nor v4.1.1 adds a key type. Under v1.8 the openness of the classical code earns nothing here. source

Placement in the band The top of the band rather than a 0 or a 1: there is no post-quantum component to verify, but nothing about the chain is marketed as quantum-safe, so its position does not rest on marketing.

The deployment dimension is not a separate judgement. It is Tier 5 expressed as a number. See the tier mapping.

How it compares

All 80 rated chains on the 0 to 100 scale. Terra Classic is marked. Select any point to open that profile.
Terra Classic 14.5

Nearest chains in the ranking

The 9 chains Terra Classic sits among, out of 80 rated. The last column is the gap in Hardy points from Terra Classic.

Rank Chain Tier Hardy vs LUNC
33 Neo 4: Debating 17.0 +2.5
34 Dash 5: Exposed 16.5 +2.0
35 Bitcoin 4: Debating 14.5 level
36 Sonic 5: Exposed 14.5 level
37 Terra Classic this chain 5: Exposed 14.5
38 Ethereum Classic 5: Exposed 13.0 -1.5
39 Flare 5: Exposed 13.0 -1.5
40 Internet Computer 5: Exposed 13.0 -1.5
41 TON 5: Exposed 11.0 -3.5

Roadmap

  1. 15 April 2026 shipped

    Governance passes proposal 12218, upgrading the chain to node v4.0.0 on Cosmos SDK v0.53.6 at height 28,214,400. The upgrade adds no key type. source

  2. 5 May 2026 proposed

    A Post-Quantum Roadmap RFC for Terra Classic is posted to the community forum for informal, non-binding discussion until 5 June 2026. It selects ML-DSA for consensus and a hybrid path for wallets, and it says a governance proposal would open the formal comment window. source

  3. 26 October 2026 shipped

    Node v4.1.1 takes effect at height 31,010,600 under proposal 12233, which passed on 19 October 2026. It fixes bugs, keeps Cosmos SDK v0.53.6 and changes no signature scheme. source

  4. No date published proposed

    A governance proposal to open the formal RFC comment window, the first step the RFC itself sets out. None was found among the proposals submitted up to 23 October 2026. source

If holders never migrate

No stated policy

Nothing adopted or put to governance says what happens to LUNC in accounts that never move to post-quantum keys. The pre-formal RFC proposes a hybrid wallet path in which classical signatures stay valid during a transition and does not address dormant accounts.

As of 23 October 2026. Published beside the score, not in it. Every chain's stance is compared on the commitments page.

Exposure

Exposure measures how much of the chain's value already sits behind a public key that an attacker can record today and break later. This is the part of the threat that a future upgrade cannot undo.

Terra Classic uses the Cosmos SDK account model. An address is a Bech32 hash of the account's secp256k1 public key, so a never-used address has not published its key, but the key goes on-chain with the account's opening transaction and stays there. Staking LUNC needs a signed delegation, so actively held LUNC sits behind revealed keys. Validator consensus keys are Ed25519 keys published by design, and a public node listed 90 bonded validators on 23 October 2026. The columbus-5 ledger carries balances forward from the Columbus mainnets that began in 2019, so keys revealed by signatures in that earlier history are public too; no measurement of the exposed share has been published, so the score rests on the address model. LUNC bridged to Ethereum, BNB Smart Chain and Solana through governance-owned Hyperlane contracts, and LUNC sent over IBC, is represented on those chains and protected by their signatures, not Terra Classic's.

What this rating means for you

If you hold Terra Classic

Terra Classic runs quantum-vulnerable signatures with no published post-quantum plan that we could find. Nothing here is urgent today, and there is also nothing scheduled to change it.

Editorial guidance from the Hardy Index.

Embed this rating

Paste this anywhere to show Terra Classic's current rating. It renders live from the index, so it updates when the rating does, and the review date is written into the image. There is nothing to sign up for and nothing to pay. 

<a href="https://hardyindex.com/chains/terra-classic"><img src="https://hardyindex.com/badge/terra-classic.svg" width="260" height="76" alt="Quantum readiness rated by the Hardy Index"></a>

The image is /badge/terra-classic.svg. It is a plain SVG with no script and no tracking, it sets no cookie, and it records nothing about whoever loads it.

Questions

Is Terra Classic quantum-safe?

No. LUNC accounts sign with ECDSA on secp256k1 and validators sign with Ed25519, both of which a large enough quantum computer would break. No post-quantum key type is available on mainnet, and the v4.1.1 upgrade of 26 October 2026 did not add one.

Does Terra Classic have a post-quantum plan?

Not an adopted one. A contributor to the node software posted a Post-Quantum Roadmap RFC in May 2026 that selects ML-DSA for validators and a hybrid ML-DSA path for wallets, and it drew supportive replies. The author described it as an informal, non-binding discussion, and the governance proposal meant to open the formal RFC process has not been submitted.

Does the Cosmos SDK's post-quantum release protect LUNC?

No. ML-DSA-65 keys arrived in Cosmos SDK v0.55. Terra Classic runs SDK v0.53.6, and its v4.1.1 upgrade of 26 October 2026 kept that version, so no LUNC holder or validator can use an ML-DSA key on mainnet.

Are LUNC public keys already exposed?

For actively held LUNC, yes. An address is a hash of the key and hides it until the account signs, but sending or delegating reveals it, and the chain's history back to the 2019 Columbus mainnet is public. Those keys could be recorded now and attacked later by a quantum computer.

Sources

  1. Terra Classic mainnet transactions, heights 30,962,000 to 30,962,700 Terra Classic (public node API) · primary · checked 23 October 2026
  2. Terra Classic consensus parameters Terra Classic (public node API) · primary · checked 23 October 2026
  3. Terra Classic node information Terra Classic (public node API) · primary · checked 23 October 2026
  4. Terra Classic current upgrade plan Terra Classic (public node API) · primary · checked 23 October 2026
  5. Proposal 12233: Software Upgrade: Terra Classic Core v4.1.1 Terra Classic governance (public node API) · primary · checked 23 October 2026
  6. Proposal 12218: Software Upgrade to v4.0.0 (Cosmos SDK v0.53.x) Terra Classic governance (public node API) · primary · checked 23 October 2026
  7. Proposal 12232: Hyperlane on Terra Classic, Delivery Report and Payment Proposal Terra Classic governance (public node API) · primary · checked 23 October 2026
  8. classic-terra/core Terra Classic (GitHub) · primary · checked 23 October 2026
  9. classic-terra/core v4.1.1 release Terra Classic (GitHub) · primary · checked 23 October 2026
  10. classic-terra/core v4.0.1-patch.3 release Terra Classic (GitHub) · primary · checked 23 October 2026
  11. classic-terra/core go.mod at v4.1.1 Terra Classic (GitHub) · primary · checked 23 October 2026
  12. v14_1 Proposal: Software Upgrade (Cosmos SDK 0.53.x) Terra Classic (GitHub) · primary · checked 23 October 2026
  13. Post-Quantum Roadmap RFC (Pre-Formal Discussion) Terra Classic community forum · primary · checked 23 October 2026
  14. Post-Quantum Roadmap RFC for Terra Classic, chapter files fragwuerdig (GitHub) · primary · checked 23 October 2026
  15. Post-Quantum Roadmap RFC: Roadmap Phases fragwuerdig (GitHub) · primary · checked 23 October 2026
  16. Post-Quantum Roadmap RFC: Decision Log fragwuerdig (GitHub) · primary · checked 23 October 2026
  17. Proposal to the Terra Classic Community: LUNC Must Become Quantum Resistant Terra Classic community forum · secondary · checked 23 October 2026
  18. Columbus-5 Terra (GitHub) · primary · checked 23 October 2026
  19. Columbus genesis backgrounder (GENESIS.md) Terra (GitHub) · primary · checked 23 October 2026
  20. Accounts (Cosmos SDK v0.53) Cosmos SDK documentation (Cosmos Labs) · primary · checked 23 October 2026
  21. Post-quantum keys Cosmos SDK documentation (Cosmos Labs) · primary · checked 23 October 2026
  22. Cosmos SDK v0.55.0 release Cosmos SDK (GitHub) · primary · checked 23 October 2026
  23. FIPS 204: Module-Lattice-Based Digital Signature Standard (ML-DSA) NIST · primary · checked 23 October 2026
Cite this rating

A rating is only true as of the day an editor last reviewed it, so both forms below carry that date and the methodology version, with the date its cited sources were last checked. If you are quoting the score, quote those too.

Plain text

The Hardy Index (2026). Terra Classic: quantum readiness assessment. Hardy Score 14.5 of 100, Tier 5: Exposed. Methodology v1.8. Last reviewed 4 November 2026; sources checked 13 November 2026. https://hardyindex.com/chains/terra-classic

BibTeX 
@misc{hardyindex_terra_classic_2026,
  author       = {{The Hardy Index}},
  title        = {Terra Classic: quantum readiness assessment},
  year         = {2026},
  howpublished = {\url{https://hardyindex.com/chains/terra-classic}},
  note         = {Hardy Score 14.5 of 100, Tier 5: Exposed. Methodology v1.8},
  urldate      = {2026-11-13}
}

The whole dataset is reusable under the terms on the about page. A machine-readable version of this page is at /chains/terra-classic.md.

This is a security-readiness assessment, not investment advice.