Qatoshi: the next signature

Same Bitcoin. New assumptions. A closer look at the public record and the research shaping what comes next.

A question worth inspecting

Introducing Qatoshi, an independent Bitcoin × quantum observatory. We start with the public record: the structure of an output, the material it reveals, and the assumptions behind a proof. The interface is built to make those details easier to inspect.

Quantum computing has brought a new vocabulary into the Bitcoin conversation. Exposure, migration, commitments and post-quantum signatures describe different questions. Qatoshi puts them in separate, inspectable views so that a broad narrative becomes a concrete starting point for research.

The experience is intentionally direct. Open the terminal. Change a message. Read a locking script. Follow the source. Each action is small enough to understand, and each result gives you something specific to examine.

Read the output

Qatoshi's output reader recognizes common locking-script structures. Select an example or paste public hexadecimal script bytes. The reader breaks a recognized pattern into its opcodes and committed material, then links to the relevant specification.

A Taproot output exposes a 32-byte public key. Key-hash outputs instead contain a hash commitment and typically reveal a signing key at spending. The script pattern alone cannot establish whether a key was disclosed earlier or reused elsewhere. The reader identifies structures; it does not certify an address as quantum-safe.

Follow the proof

The commitment terminal runs SHA-256 in your browser. It hashes your message, combines it with seven fixed demonstration leaves and constructs an eight-leaf Merkle tree. Three sibling hashes connect the first leaf to the committed root.

Then comes the useful part: alter the message while retaining the original root and path. Verification fails. Restore the original message and it passes. Rebuild with a different message and you get a new commitment. The result comes from computation rather than a prerecorded success animation.

This experiment illustrates data integrity. It is not a digital signature, a Bitcoin transaction or a quantum computer. Your message stays in the browser; the terminal does not send it to a server.

Keep the proposal status visible

The research log connects present Bitcoin output rules with proposals under discussion. BIP 360 proposes Pay-to-Merkle-Root, removing the Taproot key path in favor of a script-tree commitment. Its draft targets long exposure; protection during spending can still require future post-quantum signatures.

BIP 361 is a draft migration and legacy-signature sunset framework, dependent on a future post-quantum signature proposal. A draft is a research document, not an activated network rule. Qatoshi keeps that distinction visible and links to the primary documents.

An observatory, one inspection at a time

The site also reads a Bitcoin mainnet block-height and fee snapshot from the public mempool.space API. These network readings are separate from the browser-local commitment experiment. If the API is unavailable, the site shows that state instead of substituting invented readings.

Qatoshi brings the terminal, output reader and research log into one focused experience. The aim is to make a difficult conversation more tangible: start with what is visible, inspect what is computed, and keep following the work that remains open.

Same Bitcoin. New assumptions. Open the terminal.

Explore Qatoshi: https://qatoshi.vercel.app/

Sources
BIP 341 — Taproot
https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki

BIP 360 — Pay-to-Merkle-Root (Draft)
https://github.com/bitcoin/bips/blob/master/bip-0360.mediawiki

BIP 361 — Post Quantum Migration and Legacy Signature Sunset (Draft)
https://github.com/bitcoin/bips/blob/master/bip-0361.mediawiki

mempool.space REST API
https://mempool.space/docs/api/rest
