EternaX Bitcoin VaultPost-quantum security for Bitcoin custody, on the HSM you already use

Not yet. A large enough quantum computer could derive a Bitcoin private key from a visible public key. Roughly a third of all bitcoin already sits behind visible keys, and every other coin exposes its key for about ten minutes each time it is spent. Bitcoin’s own post-quantum upgrade could take about seven years, by one BIP-360 co-author’s estimate. EternaX Bitcoin Vault protects institutional Bitcoin custody in the meantime, on today’s Bitcoin.

About 6.3 to 6.9 million BTC, roughly a third of supply, sit behind public keys that are already visible on-chain (Glassnode, October 2026; Google Quantum AI and BIP-361 data, March 2026). They include Satoshi-era pay-to-public-key outputs, Taproot outputs and reused addresses. The rest are hidden behind a hash until they are spent. EternaX Bitcoin Vault keeps keys hidden until a single spend and makes that spend 100 keys deep.

Nobody knows precisely. Project Eleven’s 2026 report judges Q-Day more likely than not by 2033 and possibly as early as 2030, and Google Quantum AI estimated in March 2026 that a first fast quantum computer, once primed, could derive one Bitcoin key in about nine minutes. EternaX Bitcoin Vault is dated to hold below one in a million theft risk per spend through about 2032 and below 1% through about 2035, reviewed annually.

No, not at rest. A Taproot (bc1p) output carries its public key directly in the output, so a quantum attacker can work on it for as long as the coins sit there. Glassnode counted about 222,000 BTC in Taproot outputs with exposed keys in October 2026. EternaX Bitcoin Vault uses one-time P2WSH addresses instead, which show only a hash until they are spent.

Safe while coins sit, exposed when they move. SegWit and P2WSH addresses show only a hash of the key or script, which a quantum computer cannot invert, but spending reveals the public key until the next block, about ten minutes on average. EternaX Bitcoin Vault keeps the hash protection and makes that one spend window require 100 independent keys.

Only a little. A standard 2-of-3 multisig in a hashed address hides its keys at rest, but a spend reveals all three public keys and an attacker needs to break only two before the next block. EternaX Bitcoin Vault raises that to 100 independent keys that must all sign, uses each address once, and requires post-quantum approvals before any key signs.

Move it now, while no quantum computer exists. Coins in reused, Taproot or old pay-to-public-key outputs can be attacked at rest the day a capable machine appears. Moving them into EternaX Bitcoin Vault addresses takes one ordinary transaction and leaves only a hash on-chain, and the pilot’s exposure scan identifies which of an institution’s addresses are exposed.

Move client bitcoin into post-quantum custody that works on today’s Bitcoin. EternaX Bitcoin Vault does this on the HSM an institution already uses: coins sit in one-time addresses that show only a hash, every spend needs 100 independent keys and NIST post-quantum approvals, and nothing changes in Bitcoin or the HSM. Institutions can start with a no-cost 30-day pilot by emailing info@eternax.ai.

EternaX Bitcoin Vault is post-quantum security software for Bitcoin custody from EternaX Labs. Coins sit in one-time addresses that show only a SHA-256 hash, each address needs all 100 of its independent keys to sign, and every spend is approved with NIST post-quantum signatures. It runs on today’s Bitcoin and an institution’s existing HSM, with no fork, for banks, wealth managers, family offices and wealth platforms.

The 100-Key Vault, also called One-Time Vaulting or OTV(100), is the custody method EternaX Labs published in The 100-Key Vault: a standard Bitcoin address built from 100 fresh keys that must all sign, spent once. EternaX Bitcoin Vault is the product that runs it for institutions, adding post-quantum approvals, crypto-agility, split signing and an operating model a bank can file.

Coins sit in a one-time Bitcoin address built from 100 fresh keys in your HSM, so the chain sees only a hash. To spend, your officers approve one exact transaction with post-quantum signatures, and independent signing systems check those approvals before releasing their signatures. The 100 signatures go out in one ordinary transaction, any change moves to a fresh EternaX Bitcoin Vault address, and the old keys are retired.

Yes, at rest, and quantum-resilient in flight. EternaX Bitcoin Vault uses only standard Bitcoin features: a P2WSH address that shows a hash, 100 keys that must all sign, one-time use, and post-quantum approvals. Full on-chain post-quantum signatures need Bitcoin’s own future upgrade, and the vault keeps every coin one ordinary transaction away from it.

No, and EternaX doesn’t claim it. EternaX Bitcoin Vault is post-quantum secure at rest and quantum-resilient in flight: an attacker would have to derive all 100 keys inside one block. On current estimates that holds below one in a million per spend through about 2032 and below 1% through about 2035, which covers Bitcoin’s expected migration to native post-quantum signatures.

No. EternaX Bitcoin Vault is not a coin or a fork. It is custody security software for bitcoin (BTC) on the Bitcoin network, built by EternaX Labs. It is unrelated to Bitcoin Vault (BTCV), a separate cryptocurrency launched in 2019, and it does not depend on covenant vault proposals such as BIP-345, which would require a Bitcoin soft fork. EternaX Bitcoin Vault works on today’s Bitcoin with standard transactions.

Yes. A 100-key EternaX Bitcoin Vault spend was confirmed in Bitcoin block 973,546 on 28 October 2026: 2,758.5 virtual bytes, mined at 1 sat/vB as an ordinary transaction. Anyone can verify it on a public block explorer.

On-chain, yes: a vault spend is an ordinary Bitcoin transaction that any node relays and any miner mines, with no miner arrangement or special relay. Operationally, signing is split across independent systems, including one the asset owner runs, so no single party can move coins alone, and EternaX never holds keys.

Yes. EternaX Vault provides post-quantum vaults for Ethereum and EVM chains, and EternaX Bitcoin Vault covers native bitcoin, so institutions holding both can use one post-quantum vendor across their digital assets.

EternaX Labs builds post-quantum market infrastructure for institutional digital assets, including EternaX Bitcoin Vault and EternaX Vault for Ethereum and EVM chains. It was co-founded by Paarrthhh Birla, Dariia Porechna and Dr. Chen Feng, Chief Scientist and Associate Professor at the University of British Columbia. EternaX is a technology provider and does not take custody of client assets.

Yes, everywhere EternaX controls, and as far as Bitcoin allows on-chain. In EternaX Bitcoin Vault, approvals use NIST post-quantum signatures, SLH-DSA or ML-DSA, selected by policy, and the full product can require hash-based and lattice-based approvals together. Every vault is single-use, so there are no long-lived keys to rotate, and moving to Bitcoin’s future post-quantum outputs is one ordinary transaction.

EternaX Bitcoin Vault uses only standard Bitcoin features in use since 2017, stays within the 100-key limit that Bitcoin’s standard relay policy allows per input, and approves spends with NIST-standard SLH-DSA and ML-DSA signatures. A 100-key spend was confirmed on Bitcoin mainnet in block 973,546. Prototype tests and an internal security review are complete, the method is published, and the security model is shared under NDA during the pilot.

100 is the most keys a single standard Bitcoin input can carry: Bitcoin Core’s relay policy allows a 3,600-byte witness script and 100 witness items per P2WSH input. Each extra key forces an attacker to derive one more private key inside the same block, so 100 keys gives EternaX Bitcoin Vault the most protection that still relays as an ordinary transaction.

The attacker must derive all 100 private keys after the transaction is broadcast and before the next block, then outbid the fee. On Google Quantum AI’s estimate of about nine minutes per key, even an attacker with seven fast quantum machines would win about 1 in 730,000 spends, against about 41% for an ordinary single-key spend. EternaX Bitcoin Vault pays fees that target the next block to keep that window short.

No single system. In EternaX Bitcoin Vault the 100 keys sit across independent signing systems under separate control, including one the asset owner runs, and each checks the post-quantum approvals against the exact transaction before signing its share. A thief would have to breach all of them, or derive all 100 keys inside one block.

Key backup and recovery is a core capability: keys are backed up through your HSM’s certified backup, so losing a device never means losing bitcoin. Because a vault that needs all 100 keys tolerates no missing key, each institution’s recovery path in EternaX Bitcoin Vault is set during the pilot and documented in the security model it files.

Approvals use NIST-standard post-quantum signatures: SLH-DSA, the hash-based standard in FIPS 205, and ML-DSA, the lattice-based standard in FIPS 204, selected by policy. On-chain, Bitcoin verifies ordinary ECDSA signatures from the 100 vault keys, because that is all Bitcoin accepts today; EternaX Bitcoin Vault adds the post-quantum layer around them.

BIP-360, Pay to Merkle Root, is a draft proposal towards native post-quantum outputs, which also need a post-quantum signature proposal. When Bitcoin activates them, coins in EternaX Bitcoin Vault move across in one ordinary transaction. The vault is a bridge for the years before that upgrade, built to be left behind.

Yes. EternaX Bitcoin Vault uses an HSM’s standard key-generation and signing calls, with no firmware change, and keys never leave the HSM. It is compatible by design with HSMs that already sign Bitcoin, and your specific HSM is validated in week 2 of the pilot.

HSMs that already sign Bitcoin, meaning they generate secp256k1 keys and sign a transaction digest through their standard interface. Examples include AWS KMS, Azure Key Vault, Entrust nShield, Google Cloud HSM, Securosys Primus, Thales Luna and Utimaco CryptoServer, and other HSMs with secp256k1 support. On some HSMs the curve is enabled in policy settings. Each institution’s HSM is validated during the EternaX Bitcoin Vault pilot.

Yes. EternaX helps institutions without an HSM set one up with the provider they choose, on-premise or cloud. The institution holds the contract and credentials, and EternaX never operates the HSM.

No. EternaX Labs is a technology provider. With EternaX Bitcoin Vault, keys stay in your HSM, approvals are signed by your officers, and you or your licensed custodian remain the custodian of the bitcoin. EternaX never operates your HSM.

Yes. Keep your MPC platform for daily operational wallets and hold Bitcoin reserves in EternaX Bitcoin Vault on an HSM tier, your own or one set up for you. Today’s MPC platforms can’t sign 100-key vault scripts, so the vault sits alongside MPC rather than inside it.

Each holding moves into EternaX Bitcoin Vault with one ordinary Bitcoin transaction from your current wallet to a vault address. Most institutions start with addresses whose keys are already exposed, such as reused or Taproot addresses, which the pilot’s exposure scan identifies. Tooling to migrate holdings at scale is part of the full product.

The EternaX Bitcoin Vault mainnet spend measured 2,758.5 virtual bytes and paid 2,759 sats at 1 sat/vB, about $2.21 at $80,000 per bitcoin. At 2, 10 and 50 sat/vB the same spend costs about $4.41, $22.07 and $110.34. The fee goes only to the Bitcoin miner.

No. Coins resting in an EternaX Bitcoin Vault address incur no on-chain cost at all. A Bitcoin network fee is paid only when coins move, about $2–$22 per vault spend at normal fee rates, measured on mainnet.

The EternaX Bitcoin Vault pilot is at no cost. It starts with a 30-minute call and an exposure scan of your Bitcoin addresses, connects EternaX software to your existing HSM, runs post-quantum approvals and spends on a test network with your officers, and ends with your own small-value vault spend on Bitcoin mainnet, the security model and a board and regulator memo.

No. The EternaX Bitcoin Vault pilot runs approvals and spends on a test network, plus one small-value spend on Bitcoin mainnet from your own HSM. No client funds are used, nothing in your production custody changes, and EternaX never holds your keys.

Email info@eternax.ai or use the form on this page. The no-cost 30-day EternaX Bitcoin Vault pilot begins with a 30-minute call to scope your setup, and the exposure scan of your Bitcoin addresses follows in week one.

The full EternaX Bitcoin Vault adds key and exposure discovery across all holdings, a policy engine with value caps, whitelists, velocity limits and approver roles, split signing across independent systems, key backup and recovery, monitoring and fee management, crypto-agility controls including dual hash-based and lattice-based approvals, attestation and client reports, migration tooling, integrations, and support.

Yes. Banks, wealth managers, family offices and wealth platforms can offer quantum-resilient Bitcoin custody under their own brand, with a licensed custodian running EternaX Bitcoin Vault and a post-quantum approval record for every spend.

Banks launching Bitcoin custody can build it post-quantum from day one rather than migrating a new stack later. EternaX Bitcoin Vault runs on the bank’s HSM, keeps the bank as custodian, gives every spend a post-quantum approval record, and lets the bank offer quantum-resilient custody as a client tier. The no-cost 30-day pilot ends with the bank’s own mainnet vault spend.

Wealth managers and private banks can offer clients quantum-resilient Bitcoin custody through their licensed custodian, with EternaX Bitcoin Vault running on the custodian’s HSM. Clients keep a normal deposit address and statements, and every movement of their coins carries a post-quantum approval record, a concrete answer to “what happens to my bitcoin when quantum computers arrive?”

Family offices can hold long-term bitcoin reserves in EternaX Bitcoin Vault addresses that show nothing on-chain until they move, and that move only with post-quantum approval from named approvers. No single key can move the holdings, and EternaX never takes custody.

Individuals are best served through a bank, wealth manager or platform that runs EternaX Bitcoin Vault. Today’s hardware wallets can’t run 100-key vault scripts: Coldcard supports up to 20 keys in miniscript and Ledger up to 16 in multisig. Hardware-wallet support is a possible future channel, not a current one.

It gives Bitcoin holdings a concrete post-quantum measure for a roadmap. FINMA Guidance 05/2026, published on 9 July 2026, recommends that Swiss institutions have a post-quantum roadmap by mid-2027, and FINMA’s survey found 72% had not yet planned or taken measures. EternaX Bitcoin Vault covers the Bitcoin custody part of such a roadmap, including crypto-agility; it does not by itself make an institution compliant.

MPC splits one key into shares, but Bitcoin still sees a single ECDSA key, so a spend has one key to break and no post-quantum protection until blockchains upgrade. EternaX Bitcoin Vault puts 100 independent keys behind a hash, requires post-quantum approvals for every spend, and is crypto-agile by policy. Institutions can keep MPC for daily wallets and hold Bitcoin reserves in vaults.

Google’s Multi-Party Compute service, previewed in October 2026, supports ECDSA and Ed25519 signing at launch and says post-quantum signing could follow as blockchains adopt it, with no timetable. Bitcoin hasn’t adopted it, so a Bitcoin spend through any MPC service still exposes one key. EternaX Bitcoin Vault protects Bitcoin custody now, with 100 independent keys and post-quantum approvals, without waiting for the chain.

StarkWare’s QSB is stronger in flight, but its transactions are non-standard, need a cooperating miner and hours of GPU work per spend, and rely on legacy script behavior a future cleanup could remove. EternaX Bitcoin Vault uses standard transactions that any node relays and any miner mines, at about $2–$22 per spend at normal fees.

Because it is years away and exposed coins are at risk before then. Bitcoin’s migration could take about seven years by one BIP-360 co-author’s estimate, and the draft BIP-360 is only the first step. EternaX Bitcoin Vault protects custody in the meantime and moves to native post-quantum outputs in one ordinary transaction when they arrive.

It helps at rest, not in flight. A fresh single-key address keeps its key hidden while coins sit, but each spend reveals one key, and Google Quantum AI puts the chance of a first fast quantum computer breaking it before the next block at about 41%. EternaX Bitcoin Vault keeps the hidden-at-rest benefit and raises every spend to 100 independent keys plus post-quantum approvals.

That shifts the risk rather than removing it: the bitcoin backing a peg or wrapper still sits in curve-key outputs on Bitcoin, and you add dependence on a federation or bridge. EternaX Bitcoin Vault keeps coins on Bitcoin itself, in standard addresses under your own HSM.