👛 Wallet compatibility

Bit-SIGN needs a wallet that can do two specific things: show you one of its addresses, and sign a piece of text with that address. Most wallets do the first. Fewer do the second, and that is the only thing that decides whether yours works here.

Native segwit only

Use an address beginning bc1q. Legacy 1…, wrapped 3… and taproot bc1p… addresses are not supported for signing here. Every wallet below can produce a bc1q address.

🔏 What is the line you sign?

After you enter your address, the account page gives you one line that looks like this:

• BIT-SIGN — says what the signature is for. A signature made for this site cannot be reused to sign in anywhere else.
• your address — the address you typed. The signature must come from the key behind this exact address, so make sure your wallet signs with the same one.
• the 16-character code — a random one-time code made for this sign-in only. It is what stops anyone replaying an old signature: every sign-in gets a new code, and each code works once.

• Copy it exactly. The wallet signs the precise characters, so a missing letter, an added space or a line break makes the signature fail. Use the 📋 button rather than typing it.
• Valid for 15 minutes. If you take longer the code expires; press GET THE LINE TO SIGN again and sign the new line.
• Signing it is safe. It is a text message, not a transaction: it moves no bitcoin, costs nothing, and your private key never leaves the wallet. Only the signature is pasted here.
• Use the same address every time. Your account is the key behind the address you sign with. Every receiving address in a wallet is a different key, so signing in from another address opens a different account — new username, nothing saved. Pick one address for sign-ins (the first one is fine, it may stay empty) and label it in your wallet, e.g. "Crypttron login". Don't use the wallet's "next unused" address.

How to sign it

1. In your wallet copy one receiving address (starts with bc1q) — not an xpub, not a change address.
2. On the account page paste it and press GET THE LINE TO SIGN. A reminder appears first: note this address — it is your only way back into the account, and we cannot recover it. It offers to remember the address in your browser; that is off by default, and if you tick it the address is kept on your device only and prefilled next time. Then press 📋 to copy the line.
3. Sparrow: Tools → Sign/Verify Message · Electrum: Addresses tab → right-click the address → Sign/verify message.
4. Check the Address field shows the same address, paste the line into Message, press Sign, copy the signature.
5. Paste the signature back and press VERIFY & SIGN IN.

Videos: ▶ signing in Sparrow · ▶ signing in Electrum · written guide for any wallet · ▶ how Bit-SIGN works (90 s). Download wallets only from sparrowwallet.com or electrum.org.

Desktop

Mobile

Hardware

⛔ Exchanges and custodial apps

Coinbase, Binance, Kraken, Cash App, Revolut, Strike and every similar service cannot be used, and this is not a missing feature — it is what custody means. The address they display belongs to them, not to you, so there is no key of yours to sign with and they will not sign on your behalf. If your bitcoin lives only on an exchange, you will need to make a wallet to use Bit-SIGN.

🆕 No compatible wallet? Make one in two minutes

You do not need to move any bitcoin, and you do not need to touch the wallet that holds yours. A signature proves possession of a key — the balance behind it is never examined and is irrelevant.

1. Install Sparrow (desktop) or BlueWallet (phone).
2. Create a new wallet, keeping the default native-segwit setting.
3. Write the seed words down. That key is your Crypttron account — there is no password reset and no recovery email, so losing the words loses the account.
4. Copy its first bc1q… receive address and use it to sign in.
5. Leave it empty forever. It works exactly the same.

▶ WATCH HOW IT WORKS GO TO SIGN IN

If a signature is rejected

• You requested a new line after signing. Each request replaces the last one, so an earlier signature stops matching. Get the line once, sign that, paste it back.
• The address doesn't match. Sign with the same address you typed in — a different address is a different key.
• Wrong address type. It must begin bc1q.
• It expired. Lines are valid for fifteen minutes. Request a fresh one.
• Something was truncated. Copy the whole line, including everything after the last |, and the whole signature.
• It signed you in — but into an empty account. You used a different address than last time. That is a different key, so it is a different account. Sign in again with the address you first used (see what the line means).

Still stuck? Send a signed message — or if signing is the thing that's broken, that page explains the setup too.