Contact — CRYPTTRON

✉ Reach the operator

Crypttron holds no email addresses and issues no accounts, so a message needs some other way of showing a person wrote it. It carries a wallet signature: you sign the text with a key you already control, and that signature travels with it.

The reasoning is practical. An unguarded form is full of junk inside a week. A captcha exports your behaviour to whoever supplies it. An email box becomes a list of people, and a list of people is a liability — it can leak, and it can be demanded. A signature avoids all three: costly for a machine to produce at volume, free for you, and it reveals nothing but a key you chose to use.

Send a message

1 · A Bitcoin address you control 2 · Subject (optional) 3 · Message

🔑 Setting up a signing keyone-time

Two capabilities are needed from a wallet: it has to show you one of its addresses, and it has to sign arbitrary text with that address. Plenty of wallets do only the first. The table below is where the feature lives in the ones that do both.

Nothing here touches the blockchain. Signing text is arithmetic on a key — it produces no transaction, costs no fee, and leaves no on-chain record. It works with the device unplugged from the internet. A signature over text is also unable to authorise movement of funds; that requires signing a transaction, which is a different operation entirely and is not what happens here.

Wallet	Where the feature is
Sparrow desktop	Install from sparrowwallet.com, create a wallet, record the seed words. Open the Addresses tab and copy any `bc1q…` entry. Right-click the same row and pick Sign/Verify Message.
Electrum desktop	The Addresses tab is hidden until you enable View → Show Addresses. Copy a receiving address, then reach signing through Tools → Sign/verify message or by right-clicking the address.
BlueWallet phone	Inside the wallet, open the ⋯ menu, then Addresses. Tap any address and choose Sign/Verify.
Trezor hardware	Copy a receive address in Trezor Suite, then use the suite's Sign & verify tool and approve on the device screen.
Ledger, Coldcard hardware	Neither vendor app signs text. Pair the device with Sparrow or Electrum and sign from there — the private keys stay on the hardware throughout.
Exchange apps	Coinbase, Binance, Kraken and similar cannot be used. The address they display belongs to the exchange, and they will not sign anything on your behalf.
Exodus, Trust, Muun, Phoenix	These omit message signing altogether. Nothing is wrong with them as wallets; they simply lack the feature this needs.

Rather not involve your main wallet? Then don't. Make a fresh wallet, leave it completely empty, and use that. What a signature demonstrates is possession of a key — the balance behind it is irrelevant and never examined. Any wallet above will generate one in about two minutes at no cost. Keep the seed words if you'd like the same identity to persist across messages; discard them if you wouldn't.

What gets stored: the address you signed with, and your message. There is no email field, no account record, and no third party in the loop.