This looks pretty impressive.
Thank you !
Do you guys have a design or a price in mind?
If you're asking about visual designs, we do have an idea for our first 12 denomination series of coin.
We're in the early days of industrial design, so at this point we have not yet determined if we can make these tokens out of metals or we will be forced to use non-metallic tokens due to Faraday effects blocking NFC.
We don't have a clear picture on pricing yet for similar reasons, but we would like to be competitive with existing solutions such as low end hardware wallets like ledger hw1, the btcc bitcoin tokens and open dime.
However, we may also charge a premium for the usability and security advantages that we bring to the table.
TL;DR: more work is needed and we are still figuring pricing out.
Which materials are you planning to use to mint the physical coin?
Because the precious metals might not seem affordable to everyone.
If you're planning to mint 10,000+ units in your first batch, I'd recommend using Brass.
Brass is a good idea. We are not wedded to using precious metals to manufacture Satoshium. Lower denominations might even use casino-chip like plastic.
Using a cryptoprocessor to lock
secrets in a tamper secure way is also far safer than using an easily tampered hologram (e.g.
Casascius) or a scratch-off (e.g. Little Bit of Coin)
I see that you are going to use a cryptoprocessor along with an NFC tag/chip.
Can you share some more information about the cryptoprocessor?
We plan on using a Java-card compatible cryptoprocessor with a secure element.
See top of page 6 of the white paper for details.
Inscription: Generate a bitcoin secret (private key or seed mapping to private key) unknown
to the minter but using entropy provided by the minter, with probabilistic evidence that no
cheating occurred. Optionally, the minter can view an audit report in which she can verify
the entropy she provided was probably used in the bitcoin secret. The minter can enforce an
arbitrarily high probability that her entropy was used, with more certainty requiring more
time during the inscription phase.
Do we need to use your application to generate a key, or can we generate one ourselves?
Great question !
The secret must be UNKNOWABLE even to the minter, otherwise the coin can never be "Minted" i.e. transferable to other people since the creator of the secret can never be trusted not to steal the bitcoin later :-)
Lack of unknowability of the secret is what has prevented most prior attempts at physical Bitcoin from circulation (or at least occasional transferability and re-sellability)
However, Satoshium provides a novel protocol to guarantee that the *entropy* ( but not the secret! ) provided by the minter was used in the secret generation. This assures the minter that Satoshium DEVELOPERS can never know or predict the secret and therefore the secret truly remains unknowable which allows the coin to be transferable.
Note, we do provide for a "Secret Extraction" but doing so irreversibly invalidates the "Minted" status and at that point the coin can only be redeemed but not transferred (until it's erased and and re-minted with a different inscription and proof of fundedness again, i.e. satoshium is re-usable !)