The BTextC Manifesto

It should be easy to send small(ish) amounts of bitcoin via text message. The recipient shouldn’t need a wallet, or an app, or an account. This would expand the group "people you can send Bitcoin to" from mere millions of people, those with wallets and accounts at exchanges, to anyone with a phone, i.e. billions.

Then you could send bitcoin directly as aid, and/or to those struck by crisis, a la GiveDirectly. (Yes, they'd then have to find a way to convert it -- but they would still be in immediate direct possession of aid money, which they might not even want to convert immediately, preferring to hold it to hedge against local inflation.) You could pay your share of a group expense in bitcoin, on the spot, with minimal hassle, even if the recipient has no wallet. You could immediately send money across borders to anyone with a phone, or construct programmatic bitcoin rewards which anyone with a phone could claim.

Others have thought this. But what do all of the existing ‘send bitcoin via text’ solutions demand? “Download our app / Create an account / Sign up at our site.” No, stop it, wrong. Nobody wants that--and it’s not necessary. Bitcoin comes with everything needed to transfer value via text already built in. You don’t need an account, or an app, or a site, or a token. All you need is a protocol: a repeatable way to turn the recipient’s phone number, and a password for security, into the private key which can access the transferred money.

“What? Working with raw private keys? Ones built from not-entirely-random data, therefore lower entropy? Using notoriously hackable and SIM-swappable SMS? That is horrifically unsafe and insecure and completely unacceptable!” No, stop it, wrong. I mean, I certainly wouldn’t send a million dollars this way. And I’d certainly favor Signal and WhatsApp over SMS. But the threat model for a million-dollar transaction is very very very different from the threat model for fifty bucks. For the latter, a protocol protected by decent passwords is good enough.

So what is this protocol? It’s quite simple:

  1. Take the recipient’s phone number.
  2. Pick a password, with decent length and complexity requirements.
  3. Use 1. and 2. to create a Bitcoin private key in a deterministic way.
  4. Use that private key to create its corresponding Bitcoin address.
  5. Send bitcoin to that address.
  6. Text the password to the recipient's phone number.
  7. Recipient goes through steps 1-3 again to get the address's private key.

You may be thinking: "This sounds super low level and complex!" Sure. That's why I built a web service to handle steps 1 through 4 for you. That site runs everything locally in your browser, of course, all data is ephemeral and transient, nothing is ever stored, etc. (And again, before your head explodes, the threat model for "occasionally sending $50 to your buddy" is very very different from the threat model for "a crypto whale's life savings.") This reduces the procedure to:

  1. Go to, enter the recipient's phone number, pick a password.
  2. Text that password and an explanatory URL to the recipient’s phone. (The site generates boilerplate text to copy/paste.)
  3. Send bitcoin to the generated address.
  4. Recipient goes to and uses the password they were texted to get their private key -- basically, an "electronic paper wallet" -- to be imported (or swept) into a more formal / secure wallet, then perhaps exchanged for fiat.

Note that you don’t have to use the web site at all for any of this. It’s just a convenience and a reference implementation. You can do it all yourself on an air-gapped computer in an underground bunker if you really want.

Note also that there's room for higher-level services here, such as a service to 1. generate the password and host it (but not the money!) in a kind of password escrow, 2. ensure the number is correct by having the recipient verify obscure/trivial knowledge shared by both parties, and only then 3. actually send the recipient the password. I expect you'll be able to think of more yet. This protocol is (deliberately) primitive, but it's a primitive atop which more sophisticated services could be built.

Obviously this is an alpha release -- that's why the HTML is deliberately brutalist -- and you should probably stick to testnets, for now. Even if/when you start sending real money, don't send very much.

A few potential use cases spelled out in more detail:

  1. Suppose you want to airdrop bitcoin to everyone in a given region, or with a given phone number prefix, again a la GiveDirectly. Instead of ensuring all recipients have wallets, tracking every address, etc., you can just transfer it all by phone and then have your agent help people handle it via public education sessions, easily resend any accidentally deleted messages, etc.

  2. Suppose you land in London, go for a fancy meal with acquaintances, then realize you don’t have any pounds on you. So you ask "Can I pay you with Bitcoin?" Instead of requiring the recipient to download a wallet, deal with a mnemonic phrase, figure out addresses, etc., on the spot -- unrealistically complex and obnoxious -- you just ask them for their phone number. Maybe send them a quick confirmation text to ensure you got it right. Then just come up with a witty password, send them a text with it, fire up your wallet, and transfer 0.01 BTC to the address copied from The hard part is now the witty password.

  3. Suppose you don’t even want to send bitcoin to a phone; you just want to reward whoever solves a puzzle first. You do this by making its solutions a 15-digit number and a password. Then whoever gets it first can go to, enter those values, get the private key, and claim its contents.

  4. This doesn't just work for phone numbers. It could also be used for email addresses, Twitter handles, or any other kind of unique identifier.

Of course, senders still have to perform the actual blockchain transfers themselves. (A higher-level service could do this, but would have to be a registered and regulated money transmitter, in most countries.) BTextC can’t help with that user experience, or the recpient’s experience once they receive their cryptocurrency.

But there are no additional user experiences: no account to sign up for, no app to download, nothing else to think about or keep track of. It’s simple ... and it’s already baked in, right at the protocol level, waiting to be used.

You may be wondering: can you do this with Ethereum too? And the answer is: you sure can. The algorithms are just a little different. See the very similar Texthereum Manifesto...

If you're interested in this project, feel free to contact me at