Q-day line · not yet Water level ▲ slot — Pairs aboard —

Forecast · Q-day · boarding is open

Your wallet is a public key. Two by two. Aboard.

One day a quantum computer reads the private key right off it. Give your wallet a hash-only twin key and board the pair with one memo on mainnet. Your pair is on the manifest, dated by Solana. Let it rain; keep the twin file dry.

cubitBoarding pass mainnet

FromED25519curves · exposed
ToSHA-256hashes · twin key
Passengers
2 · two by two
Tx
specimen
Seat 2/2 ✓ aboard e19b…1ea7
Board the ark → Scan an address ⌘K

free · you only pay the network fee ≈ 0.000005 SOL

01 · The forecast

Day 01 · light rain

Every Solana address…

You paste it everywhere: exchanges, airdrops, your bio.

Day 12 · the water rises

…is a public key.

32 bytes of ed25519, published forever. Same bytes, different spelling.

Day 30 · Q-day

A quantum computer runs it backwards.

Shor, 1994: from the public key straight to the private one. That is the flood.

Day 40 · everything under water

Harvest now. Forge later.

Nobody has to break in today. Every signature you ever made is on-chain, waiting.

cubitBoarding pass wallet

Passenger 1 · Solana address

86xCnPeV69n6t3DnyGvkKobf9FdN2H9oiVDdaMpo2MMY

Keyed25519
Twinnone
Noteyou share this everywhere
Seat 1/2 twin missing

02 · Why it’s called cubit

Built in cubits. Safe from qubits.

One letter apart · a cubit is 45.7 cm · a qubit breaks curves

sheet 01 · the ark · Genesis 6:15

Genesis 6:15 · the ark

300 × 50 × 30

Noah measured the ark in cubits: three hundred long, fifty wide, thirty high. We measure your twin key in hashes.

Unitcubit

1979 · SRI · CSL-98

Leslie Lamport

Described a signature built only from a hash function. Solana’s smallest unit is named after him. The answer was in the name.

Fare5,000 lamports

Twin key · W-OTS

67 chains.

SHA-256 and nothing else: 2,144 bytes, no curve aboard for Shor to read.

Seat2 of 2

03 · Ship’s manifest · live from mainnet

Billions on deck. One ark.

Read by your browser from Solana mainnet-beta, this second. Nothing cached, nothing rounded up.

A · Signed with ed25519live

—

transactions on Solana so far, every one signed with a curve key

B · Signing nowlive

—/s

new curve signatures landing on mainnet every second

C · Addressesexposed

100%

every Solana address is the public key itself, no hash in front

D · Pairs aboardaboard

—

wallets with a twin, read from the manifest this second

04 · Boarding procedure

Two by two, in three steps.

Ed is your wallet’s old ed25519 key. Hash is its new twin, made of nothing but SHA-256. They board together, and nobody can split them up afterwards.

  1. 01in your browser

    Generate the twin

    Your tab forges a Winternitz key: 67 hash chains, 2,144 bytes, no elliptic curves anywhere. It goes into a twin file only you keep.

  2. 02one signature

    Board with one memo

    Your wallet signs a single memo carrying the twin’s SHA-256 fingerprint. Solana dates it. Anyone can read it; nobody can backdate it.

  3. 03after Q-day

    Ride out the flood

    If ed25519 breaks, a signature from the twin shows the wallet was yours before the rain. Quantum search only halves a hash. It eats curves whole.

05 · Scan · Solana + Bitcoin

Is your wallet above the waterline?

Paste any Solana or Bitcoin address. Your browser reads mainnet directly. Nothing is sent to us; there is no “us”.

06 · Board · ≈ 1 minute · 1 signature

Board the ark.

Generate the twin in this tab, save the twin file, sign one memo. Free: you only pay Solana’s network fee.

07 · Manifest · passenger list

Every pair aboard.

Read straight from Solana mainnet. No indexer, no database. Every row is a memo signed by the wallet it names.

08 · Lab · W-OTS, live in your tab

Watch a hash sign.

The whole signature scheme, running here: 67 chains, 16 steps of SHA-256 each. Type anything, sign it, then try to forge it.

09 · Voyage · ship’s log

Where the ark sails next.

Research milestones, shipped one by one. Each lands on this site first.

  1. v0.1boarded

    Twin keys, on mainnet

    Twin keys in the browser, the boarding memo, the scanner, the live manifest and the cubit CLI.

  2. v0.2sailing

    Merkle twins

    Sixteen one-time keys under one root, so a twin can sign more than once. XMSS-style, still only SHA-256.

  3. v0.3charting

    On-chain ark vault

    A Solana program that releases funds only against a hash-based signature. Curves can’t open it.

  4. v0.4charting

    Migration claims

    An open spec any post-quantum fork, bridge or wallet can use to honour pairs boarded before Q-day.

10 · The ticket, not the ark

Admit oneCommunity token · Solana

$CUBIT

The protocol never needs the token: boarding is free and stays free. $CUBIT is how the crew backs the voyage.

Contract address not launched yet
Buy on pump.fun → Follow on X

No promise of returns. The token and the protocol are separate things.

Crew passNº 000001 Statusnot launched

11 · Questions from the dock

Asked on the pier.

Fair questions, answered on the record.

Q.1Quantum computers are years away. Why board now?

Because a boarding pass only counts if it is older than the flood. The day a machine can run Shor on ed25519, a fresh claim proves nothing: anyone could have made it. A memo dated by Solana today still means something then.

Q.2Does Solana enforce my twin?

Not today, and we won’t pretend otherwise. A boarding is a public, signed, dated claim. It is the evidence a post-quantum fork, bridge or wallet would need to honour it. v0.3 researches an on-chain vault that does enforce a hash signature.

Q.3What exactly goes on-chain?

One memo: cubit:v1:anchor:wots16: plus the 32-byte SHA-256 fingerprint of your twin key, signed by your wallet, plus a zero-lamport touch of the manifest address so it can be listed. No seed, no key, no personal data.

Q.4What does it cost?

The Solana network fee, about 0.000005 SOL. CUBIT charges nothing.

Q.5What if I lose the twin file?

Then the twin is gone; nobody can rebuild it, including us. Board a new one and, if you like, revoke the old fingerprint. Keep the file like a seed phrase.

Q.6Why a one-time signature?

A Winternitz key is the simplest signature that needs only a hash function. It signs once, which is exactly what a twin needs: one message after Q-day saying where your funds should go. v0.2 makes it reusable with a Merkle tree.

Q.7Is it audited?

No. The code is small, open and tested, and the scheme is textbook, but v1 has not been audited. Read the limitations before you rely on it.