Chain profile
THETA accounts and validator votes are signed with ECDSA on secp256k1 and guardian votes with aggregated BLS signatures, and Theta Labs' published quantum work estimates the cost of attacking secp256k1 without proposing anything for Theta's own signatures.
No. Theta accounts sign transactions with ECDSA on the secp256k1 curve, both in Theta's native transaction format and through its Ethereum-compatible smart contract layer, and the enterprise validator nodes that propose and finalise blocks sign their votes with secp256k1 keys too. The community-run guardian nodes that seal blocks sign with BLS on the BLS12-381 curve and have their votes aggregated. A sufficiently large quantum computer running Shor's algorithm would break all three. Theta Labs has engaged with the quantum question in research: in September 2026 its blog reported that its CTO, Jieyi Long, led a 36-author study that cut the estimated quantum cost of a central step in attacking secp256k1, and published a Q&A in which he set out what migration involves for blockchains in general. Neither post says anything about Theta's own signatures, names a post-quantum scheme for Theta, or sets out a plan, and no code, proposal or testnet for post-quantum signatures on Theta was found.
Where we are making a judgement call Two judgement calls carry this profile. The first is the tier. Theta Labs' CTO led published research on the quantum cost of attacking secp256k1, the curve Theta's accounts and validators use, and Theta Labs promoted it on its own blog. The Tier 4 floor asks for post-quantum work on the chain's own signatures, in a formal improvement proposal or a public research programme, and research into breaking a curve is not work on replacing it: neither post mentions Theta's signatures, a scheme for them or a plan. A reader who counts a core team leading quantum research on the chain's own curve as a research programme would put Theta in Tier 4, with a deployment score of 2 and a Hardy Score of 11.0 rather than 8.5. The second is migration. The Q&A acknowledges that blockchains will need protocol support, wallet upgrades, asset migration and decisions about funds that cannot move, which is the acknowledgement the 3 to 5 band asks for, but it is made about blockchains in general and never about Theta. A reader who counts it would score migration 3, adding 1.5 points, and 12.5 if the Tier 4 reading is taken as well.
ECDSA on secp256k1 for accounts, native and EVM transactions, and enterprise validator votes; BLS on BLS12-381 for aggregated guardian votes
None. No post-quantum scheme has been proposed, selected or tested for Theta.
None adopted.
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.
A role not listed is not evidenced either way. Every scheme, and which other chains share it, is in the cryptography registry.
| No. | Dimension | Score | Weight | Contribution |
|---|---|---|---|---|
| 1 | Signature scheme | 0 | 30% | 0.0 |
| 2 | Deployment stage | 1 | 25% | 2.5 |
| 3 | NIST alignment | 0 | 15% | 0.0 |
| 4 | Migration path | 2 | 15% | 3.0 |
| 5 | Exposure | 2 | 10% | 2.0 |
| 6 | Verification | 2 | 5% | 1.0 |
| Hardy Score | 8.5 | |||
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.
Theta's ledger recovers transaction signers with ECDSA on secp256k1, validator votes are signed with the same keys, and guardian votes are aggregated BLS signatures on BLS12-381. Nothing post-quantum protects THETA, TFUEL or any asset on Theta today. source
Band 1: Tier 5: Exposed.
Tier 5: Exposed. The signatures securing Theta are quantum-vulnerable, and Theta Labs' published quantum work is research on the cost of attacking secp256k1, not post-quantum work on Theta's own signatures: it proposes no scheme, plan or change for Theta. See the caveat on why this is a judgement call. source
Band 0 to 2: No post-quantum scheme named for the chain’s fund-protecting signatures, or a proprietary scheme with no public cryptanalysis.
No post-quantum scheme has been named for Theta's account, validator or guardian signatures. Theta Labs' Q&A cites NIST's draft transition timeline and says organisations need to choose standardised post-quantum replacements, but it names none and does not apply the point to Theta. source
Placement in the band The floor of the band rather than a 1 or a 2: no scheme has been named for Theta, even as an example. A reference to NIST's transition timeline in general terms is not a scheme, so there is no choice to align with a standard.
Band 0 to 2: No agreed migration path, or the proposals on the table would strand or freeze holder funds.
No migration plan for Theta exists. Theta does have a record of coordinated protocol upgrades: the node software activates changes at fixed block heights, and its thirteen activation constants, set at twelve distinct heights from January 2020 to November 2022 (two share block 8,411,427), brought in Theta 2.0, smart contracts, Theta 3.0, Ethereum-compatible RPC and Metachain support. Nothing has been proposed to carry a post-quantum scheme through that route. source
Placement in the band The top of the band rather than a 0 or a 1: Theta has repeatedly changed its protocol through height-activated hard forks, including new transaction types. Not a 3, because the migration problem has been acknowledged by Theta Labs for blockchains in general, never for Theta's own holders.
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 Theta address is the last twenty bytes of the Keccak-256 hash of the secp256k1 public key, as on Ethereum, so an account that has never signed keeps its key hidden. Any send, stake or contract call reveals it, which covers almost all THETA in use. Validator and guardian keys are public by design. source
Placement in the band The top of the band rather than a 1: never-signed addresses keep their keys hidden. Not a 3, because almost all economically active THETA sits behind a revealed key, staking to a guardian or validator needs a signed transaction, and no measurement of the unexposed share has been published.
Band 0 to 2: No post-quantum component exists, or the claims rest on marketing.
No post-quantum component exists for Theta: no code, specification or testnet implementation was found in the Theta ledger repository or elsewhere in the Theta Labs GitHub organisation. The ledger is open source, but under v1.8 the openness of classical code earns nothing here, and the attack-cost research is not a component of Theta. source
Placement in the band The top of the band rather than a 0 or a 1: there is nothing post-quantum to verify, but Theta Labs does not market Theta as quantum-safe, and its quantum posts describe research rather than claims about the chain.
The deployment dimension is not a separate judgement. It is Tier 5 expressed as a number. See the tier mapping.
The 9 chains Theta sits among, out of 80 rated. The last column is the gap in Hardy points from Theta.
| Rank | Chain | Tier | Hardy | vs THETA |
|---|---|---|---|---|
| 67 | Mina Protocol | 5: Exposed | 8.5 | level |
| 68 | MultiversX | 5: Exposed | 8.5 | level |
| 69 | Polygon PoS | 5: Exposed | 8.5 | level |
| 70 | Provenance Blockchain | 5: Exposed | 8.5 | level |
| 71 | Theta Network this chain | 5: Exposed | 8.5 | |
| 72 | THORChain | 5: Exposed | 8.5 | level |
| 73 | VeChain | 5: Exposed | 8.5 | level |
| 74 | WEMIX | 5: Exposed | 8.5 | level |
| 75 | Whitechain | 5: Exposed | 8.5 | level |
Theta Labs reports that its CTO, Jieyi Long, led a 36-author study that cut the estimated quantum resources for elliptic curve point addition, a central step in attacking secp256k1, by 86 percent. The study proposes nothing for Theta's own signatures. source
No scheme selection, improvement proposal, implementation, testnet or timeline for post-quantum signatures on Theta was found. source
No stated policy
Theta Labs' September 2026 Q&A says dormant and lost coins are the hardest case for blockchains in general, but nothing has been said about THETA or TFUEL in accounts that never move to post-quantum keys.
As of 22 October 2026. source Published beside the score, not in it. Every chain's stance is compared on the commitments page.
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.
Theta follows Ethereum's address model: an address is the last twenty bytes of the Keccak-256 hash of the public key, so an account that has received THETA or TFUEL but never signed has not revealed its key. The first signature reveals it permanently, and staking THETA to a guardian node or TFUEL to an elite edge node needs a signed transaction, so almost all THETA in active use sits behind a key that can be recorded today against a future quantum computer. Because Theta accepts the same secp256k1 keys and address derivation as Ethereum, a key that has signed on any EVM chain exposes the same address here. Validator secp256k1 keys and guardian BLS keys are public by design. Theta has its own genesis and shares no transaction history with another chain, so the exposure inheritance rule does not apply. Theta EdgeCloud, Theta Labs' GPU and AI service, is not part of the ledger and is not scored.
What this rating means for you
Theta 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.
We will email you the day this rating moves, with the changelog note that explains why. Nothing else, and nothing in between.
No. Theta accounts and enterprise validators sign with ECDSA on secp256k1, and guardian nodes sign with BLS on BLS12-381. A sufficiently large quantum computer would break both, and Theta Labs has published no post-quantum plan for the chain.
In September 2026 Theta Labs reported that its CTO, Jieyi Long, led a study that cut the estimated quantum cost of a central step in attacking secp256k1 by 86 percent, and published a Q&A on what the result means for migration. Both posts are about the threat to blockchains in general; neither proposes a scheme, a timeline or a change for Theta.
For almost all THETA in use, yes. A Theta address is a hash of the key and hides it until the account signs, but sending and staking both sign, so active holders have revealed their keys. Those keys can be recorded now and attacked later.
No. EdgeCloud is Theta Labs' GPU and AI computing service. The rating scores the signatures that protect THETA and TFUEL on the Theta blockchain and the validator and guardian signatures that finalise its blocks.
A Theta improvement proposal or a public research programme on post-quantum signatures for Theta's accounts, validators or guardians would meet the Tier 4 floor. A plan from Theta Labs naming the scheme to be used would meet Tier 3.
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.
The Hardy Index (2026). Theta Network: quantum readiness assessment. Hardy Score 8.5 of 100, Tier 5: Exposed. Methodology v1.8. Last reviewed 22 October 2026; sources checked 13 November 2026. https://hardyindex.com/chains/theta
@misc{hardyindex_theta_2026,
author = {{The Hardy Index}},
title = {Theta Network: quantum readiness assessment},
year = {2026},
howpublished = {\url{https://hardyindex.com/chains/theta}},
note = {Hardy Score 8.5 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/theta.md.
This is a security-readiness assessment, not investment advice.