Chain profile
Signs with ECDSA and Schnorr on secp256k1, finalises blocks with Avalanche votes signed by the same curve, has no post-quantum proposal, and as a fork of Bitcoin Cash inherits the early pay-to-public-key coins whose keys have been on-chain since 2009.
No. eCash, run by the Bitcoin ABC node, protects XEC with ECDSA and Schnorr signatures on the secp256k1 curve, both broken by Shor's algorithm. Its Avalanche layer, which finalises blocks and, since the November 2025 upgrade, transactions before they are mined, uses the same curve: stake proofs, delegations and votes are all Schnorr signatures on secp256k1. We found no post-quantum proposal, roadmap item or research programme from Bitcoin ABC or the eCash project. The published eCash roadmap lists Schnorr signatures as complete and names nothing post-quantum, and none of the posts on the eCash blog mentions quantum computing. eCash became a separate currency from Bitcoin Cash in a chain split on 15 November 2020, and Bitcoin Cash had split from Bitcoin on 1 August 2017, so eCash carries Bitcoin's early history, including the original pay-to-public-key outputs, about 2 million coins by Deloitte's count, whose public keys are already on-chain.
Where we are making a judgement call Two judgement calls carry this profile, and one fact belongs beside them. First, exposure inherits the measured pre-fork pay-to-public-key outputs eCash shares with Bitcoin and Bitcoin Cash, under v1.8's inheritance rule. A reader who scores eCash on its own key-hash address model, as Litecoin and Dogecoin are scored, would give exposure 4, adding 2.0 points to a Hardy Score of 8.5. A measurement of eCash itself would replace the inherited figure and could move the score either way: some inherited coins have moved on this chain since the splits, and the keys of staked coins published in Avalanche proofs are unmeasured. Second, migration scores 2 on eCash's record of scheduled upgrades. The eCash project says Avalanche lets nodes agree on upgrades without chain splits, which a reader could treat as a governance mechanism worth more; we do not, because it is a way to activate changes, not a route for moving holders to new keys, and nothing has been proposed for it to carry. A reader who weighs the record at nothing without a quantum plan would score 1, taking 1.5 points off. Third, the fact: a consensus rule in the Bitcoin ABC node, in force since the November 2020 split and raised to 32% in November 2023, sends that share of every block reward to a single fund address hard-coded in the node. The address is pay-to-script-hash, so it is controlled by whatever script stands behind it, and the sources we read do not say what that script is or who controls it. It does not change any score here.
ECDSA and Schnorr on secp256k1 for spends; Schnorr on secp256k1 for Avalanche stake proofs, delegations and votes; proof of work for block production
None deployed or proposed.
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.
eCash spends are authorised by ECDSA or by the Schnorr variant on secp256k1 that the Bitcoin ABC specification added to OP_CHECKSIG and OP_CHECKDATASIG in May 2019 and to OP_CHECKMULTISIG in November 2019. Avalanche stake proofs and votes are Schnorr signatures on the same curve. Nothing post-quantum protects XEC on mainnet. source
Band 1: Tier 5: Exposed.
Tier 5: Exposed. The signatures securing XEC and finalising its blocks are quantum-vulnerable, and neither the eCash roadmap nor the Bitcoin ABC repository holds a post-quantum plan, proposal or research programme for them. The roadmap lists Schnorr signatures as complete and names no post-quantum item. 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 eCash's spend signatures or for the Avalanche signatures that finalise blocks, so there is nothing to assess against a NIST standard. source
Placement in the band The floor of the band rather than a 1 or a 2: no scheme of any kind has been named for eCash's fund-protecting signatures, standardised or otherwise, so there is nothing for the band's upper values to credit.
Band 0 to 2: No agreed migration path, or the proposals on the table would strand or freeze holder funds.
No migration plan exists. eCash has shown it can coordinate consensus changes on a fixed schedule: the November 2023 upgrade added the staking reward output to the coinbase, the November 2025 upgrade enabled Avalanche pre-consensus and 64-bit script integers, and Bitcoin ABC 0.34.0 prepares the next upgrade for 15 November 2026. None of them touched the signature scheme. source
Placement in the band The top of the band rather than a 0 or a 1: upgrades activated on a published twice-yearly schedule, the latest in November 2025, are direct evidence that the chain can ship protocol changes. Not a 3, because nobody with authority over eCash has acknowledged quantum migration as a problem to solve.
Band 0 to 2: Public keys are exposed for effectively all accounts, or a large, measured share of total supply sits in exposed addresses.
Under v1.8's inheritance rule, published measurements of the history eCash shares with Bitcoin apply to it until one specific to eCash exists. Its chain carries Bitcoin's blocks to August 2017 and Bitcoin Cash's to November 2020, including the original pay-to-public-key outputs that Deloitte puts at about 2 million coins, roughly a tenth of supply, with keys already on-chain. source
Placement in the band The top of the band rather than a 1: the pre-fork pay-to-public-key share is the part inherited with certainty, while Bitcoin's larger address-reuse figures were measured on its history after the splits and do not transfer. Not a 3, because a measured tenth of supply with keys on-chain is a large share.
Band 0 to 2: No post-quantum component exists, or the claims rest on marketing.
No post-quantum component protects eCash, so there is nothing post-quantum to review or audit. Under v1.8 the openness of the Bitcoin ABC node earns nothing here, because it is classical code that a quantum computer would break. 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 eCash 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.
The 9 chains eCash sits among, out of 80 rated. The last column is the gap in Hardy points from eCash.
| Rank | Chain | Tier | Hardy | vs XEC |
|---|---|---|---|---|
| 56 | Celestia | 5: Exposed | 8.5 | level |
| 57 | Chiliz Chain | 5: Exposed | 8.5 | level |
| 58 | Conflux | 5: Exposed | 8.5 | level |
| 59 | dYdX Chain | 5: Exposed | 8.5 | level |
| 60 | eCash this chain | 5: Exposed | 8.5 | |
| 61 | Filecoin | 5: Exposed | 8.5 | level |
| 62 | GateChain | 5: Exposed | 8.5 | level |
| 63 | Gnosis Chain | 5: Exposed | 8.5 | level |
| 64 | Injective | 5: Exposed | 8.5 | level |
Bitcoin Cash splits from Bitcoin at the August 2017 hard fork, which the Bitcoin ABC node still records at block 478,558. eCash descends from that chain, so it shares Bitcoin's history, and every public key revealed in it, up to this point. source
eCash and Bitcoin Cash become separate currencies in a chain split at the November 2020 upgrade, which activated the ASERT difficulty algorithm and a coinbase rule funding infrastructure development. Coins unmoved since before the split exist on both chains. source
The staking reward output is added to the coinbase, paying 10% of the block reward to an address selected from the Avalanche network. Not post-quantum work, but evidence of coordinated consensus change. source
Avalanche pre-consensus is enabled, so nodes vote to finalise transactions before they are mined, alongside 64-bit script integers. The votes are Schnorr signatures on secp256k1. source
No post-quantum roadmap item, proposal or research programme for eCash's signatures was found on the eCash roadmap, the eCash blog or in the Bitcoin ABC repository at the time of writing. source
No stated policy
Neither Bitcoin ABC nor the eCash project has published a policy on coins that stay behind ECDSA or Schnorr keys, including the inherited early pay-to-public-key outputs.
As of 22 October 2026. 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.
eCash inherits two histories. Its chain carries every Bitcoin block to the Bitcoin Cash split of 1 August 2017 and every Bitcoin Cash block to its own split on 15 November 2020, and the eCash project describes it as tracing back to Bitcoin's genesis block. Each original pay-to-public-key output mined in Bitcoin's early years therefore exists here too, with its public key on-chain, and every address reused before November 2020 has revealed its key on this chain as well. Under the v1.8 inheritance rule, the measured pre-fork share applies until a measurement of eCash exists: Deloitte found that the pay-to-public-key supply has stayed practically constant at about 2 million coins, which places it in the early history that predates both splits. This follows the treatment of Bitcoin Cash and Bitcoin SV. One eCash-specific exposure is unmeasured: an Avalanche proof lists each staked coin with its public key and a signature by that key, and proofs are relayed between nodes, so the keys behind staked coins are public while the coins stay unspent. No measurement specific to eCash has been published, so coins that moved after the splits, staked coins and address reuse since are unmeasured.
What this rating means for you
eCash 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. eCash signs spends with ECDSA and Schnorr on the secp256k1 curve, and its Avalanche finality layer signs with Schnorr on the same curve. A sufficiently large quantum computer would break both. We found no post-quantum proposal, roadmap item or research programme from Bitcoin ABC or the eCash project.
No. Avalanche stake proofs, delegations and votes are all Schnorr signatures on secp256k1, which Shor's algorithm breaks as it breaks ECDSA. An attacker able to forge those keys could vote with other people's stake as well as spend other people's coins.
Yes, for the history it shares. eCash's chain contains Bitcoin's blocks up to August 2017 and Bitcoin Cash's up to November 2020, so the original pay-to-public-key outputs from Bitcoin's early years, about 2 million coins by Deloitte's count, exist on eCash with their public keys on-chain. Under the index's inheritance rule that measured share applies here until someone measures eCash itself.
A formal proposal or public research programme from Bitcoin ABC on eCash's own signatures would meet the Tier 4 floor. eCash already upgrades on a published twice-yearly schedule, so a post-quantum signature in a scheduled upgrade, with a route for holders to move their coins, would raise several of the six scores.
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). eCash: 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/ecash
@misc{hardyindex_ecash_2026,
author = {{The Hardy Index}},
title = {eCash: quantum readiness assessment},
year = {2026},
howpublished = {\url{https://hardyindex.com/chains/ecash}},
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/ecash.md.
This is a security-readiness assessment, not investment advice.