Blockchain Quantum Readiness Index / Bitcoin
L1 · UTXO
Bitcoin
Every transaction signature is elliptic-curve today, and spending from common output types reveals the public key on-chain. Two numbered drafts set out a path: BIP-360 (a new output type that keeps keys hidden) and BIP-361 (a phased sunset of old signatures). A post-quantum signature type is still only proposed, nothing is ratified and no activation date exists.
Last reviewed 2026-10-19
Is Bitcoin quantum safe?
Not yet. Bitcoin is at Stage 0 (Not started) in LimeChain's Blockchain Quantum Readiness Index, with a progress score of 13.8/100. Post-quantum accounts have only been discussed, so users have no way to keep funds out of a quantum attacker's reach.
What Bitcoin needs for Stage 1: Committed
- Stage 1 needs an official roadmap or accepted spec for PQ user accounts (U is: discussed)
Caps and adjustments
- cap 40: users cannot hold and spend funds under a production PQ mechanism on mainnet
Rosette slices
| Slice | State | Points | Weight | Reason & evidence |
|---|---|---|---|---|
| U User keys | Discussed At rest: Hidden until first spend Best option: a never-spent P2WPKH (or P2PKH/P2SH-wrapped) output whose scriptPubKey commits only to the 20-byte HASH160 of the public key; the key is revealed in the witness on first spend. Taproot (P2TR) outputs put the 32-byte output public key in the scriptPubKey (exposed), and no PQ output type is activated. |
1/10 | 25 | Spending from P2PK, P2PKH or Taproot reveals the public key on-chain; all current output types verify ECC signatures. Post-quantum signature types exist only as unaccepted proposals: the P2WOTS Winternitz BIP PR #2194 was closed unmerged, and BIP-361 requires a 'TBD Post Quantum Signature BIP'. |
| C Consensus | Not applicable | — | — | Proof-of-work: the 80-byte header carries only version, previous hash, merkle root, time, nBits and a PoW nonce, no forgeable signature (same treatment as QRL and Abelian). Coinbase outputs are user keys and fall under U. Sources 5 |
| P Proof system | Not applicable | — | — | L1 with no validity or fraud proof system. no evidence |
| B Bridges & messaging | Not applicable | — | — | The protocol spec and the complete BIP index define no bridge or cross-chain messaging. Third-party pegs and Lightning are out of scope for the L1 rating. |
| A Admin & upgrade keys | Not applicable | — | — | No admin or upgrade keys. Consensus changes are soft forks signalled by miners in the block version field and locked in by stake/threshold counting (BIP-9 style activation), not by any privileged key. Sources 8 |
| M Migration & recovery | Planned | 2/10 | 15 | BIP-360 (Pay to Merkle Root, P2MR) is a numbered BIP (merged 2026-02-11) and BIP-361 (Post Quantum Migration and Legacy Signature Sunset, merged 2026-04-14) sets out a phased sunset of ECDSA/Schnorr spends. Both are Status: Draft, with no activation date and no ratified migration plan. |
Stage gates
| Requirement | Status | Details & evidence |
|---|---|---|
| Current audit of the deployed PQ signing code (Stage 5) | Not met | not claimed |
| Admin timelock of at least 30 days with a PQ override (Stage 6, alternative to PQ admin keys) | Not met | not claimed |
| Ratified migration plan with an activation date (Stage 6) | Not met | not claimed |
| New accounts PQ or hybrid by default (Stage 6) | Not met | not claimed |
| ECC sunset enforced (Stage 7) | Not met | not claimed |
PQ adoption published, not scored
There are no PQ accounts on mainnet yet. Having PQ accounts does not mean people move to them. This tracks the share of value and accounts that actually moved, over time.
Measured exposure
No on-chain probe run yet. Bitcoin, Solana, Cosmos and Substrate probes are planned.
Evidence and sources (10)
Every non-zero rating above cites at least one of these public sources.
- github.com/bitcoin/bips/pull/2194
- github.com/bitcoin/bips/blob/master/bip-0361.mediawiki
- raw.githubusercontent.com/bitcoin/bips/master/bip-0141.mediaw…
- raw.githubusercontent.com/bitcoin/bips/master/bip-0341.mediaw…
- developer.bitcoin.org/reference/block_chain.html
- bitcoin.org/bitcoin.pdf
- raw.githubusercontent.com/bitcoin/bips/master/README.mediawiki
- raw.githubusercontent.com/bitcoin/bips/master/bip-0009.mediaw…
- github.com/bitcoin/bips/pull/1670
- github.com/bitcoin/bips/blob/master/bip-0360.mediawiki
Source: chains/bitcoin.json. Reproduce: python3 score.py chains/bitcoin.json
Building on Bitcoin?
LimeChain helps teams plan their post-quantum migration: what is exposed, what to change first, and the engineering to get there.
Talk to usOpen, repeatable scoring. Non-zero ratings need public evidence; missing evidence means unknown. Methodology v0.4 · mechanism registry 2026-10-13.