Hello --

Excited to show off something that we've been working on: the Bitcoin Note. The Bitcoin Note is a cash instrument that is backed by Bitcoin via multisig. Each note is printed with beautiful, currency-grade elements that use secure printing techniques typically reserved for government documents like microtext, raised print and foil. More importantly, each note includes a secure NFC chip which is where a multisig lives that allows you to claim the Bitcoin at any time.

We were heavily inspired by OG Bitcoin physical money like Casascius coins, however, we wanted to created a design whereby (1) anyone can spend, gift and share the Bitcoin for years to come without having to worry a sophisticated attacker who extracts a private key from under a label or scratch off and (2) trust was minimized on that part of the printer (us).

This lead us to the design we landed on for the Bitcoin Note --

• An NFC chip readable by nearly all modern smartphones
• A two part multisig where (1) we write an encrypted private key to the note (and don't keep a copy and (2) you write a user key to the note in plaintext and then load the note
• We only release the decryption key when someone cuts the note and reports this via an authenticated and encrypted way to our server
• The multisig reverts to only your key after a printed expiration date on the note
• You can re-key the user key on the note you receive if you want to hold it for a long time

The result is you do not need to trust us as the creators of the note. While, as I noted, we do not keep a copy of the encrypted private key this doesn't really matter: by the construction of the multisig, this key can never access the funds alone. Likewise, the expiration date means that even if we aren't around or refuse to allow for the claiming of a note by cutting it, the holder can wait and then use the user private key to claim.

We believe that the result of this design achieves the goal of Bitcoin that's incredibly easy to use -- like cash -- but still preserves the important quality of self-custody. Take a look at http://bitcoinnote.com/ to learn more and reserve a spot in line for our release later this summer. Any and all feedback is appreciated and I would be happy to answer any questions.