SATSCHIP™ is an NFC chip (think of the little wireless chip in your credit card) manufactured by Coinkite, an industry-leading, Bitcoin-only company focused on producing ultra-secure Bitcoin hardware. SATSCHIP holds a unique Bitcoin private key, and is embedded into the artwork. The piece carries that private key and it can never be seperated from the artwork, nor used by the artist after the art is sold.

SATSCHIP's purpose is to allow artists to embed Bitcoin scarcity and value into their works.

Any passer-by can verify the originality of the work using a simple tap of their phone. The owner of the work can use the private key to sign message to verify their ownership and control of the work at any time.

Yes. SATSCHIP comes without a private key. The setup process combines the artist's entropy (random bits) with secret entropy picked by the card.

The artist can be sure the provided entropy was used, and yet cannot change or control the ultimate private key... it never leaves the SATSCHIP.

There are a number of ways to verify it:

Tap with your phone. SATSCHIP opens a webpage verifying the card logic and public key/private key relationship.

Check it with any TAPSIGNER-ready mobile wallet.

Like most electronic devices, if stored properly, it should last decades.

No, the private key (XPRV) that never leaves the SATSCHIP.

If you changed the PIN code, they gain nothing except some wonderful artwork. If the PIN code is known to the thief, then they have complete control of the SATSCHIP.

When setting up SATSCHIP, cypherstig provides a 32-byte chain code for entropy purposes. That chain code plus the private key picked by the SATSCHIP are combined using the BIP-32 standard to derive the XPRV.

Because cypherstig provided the chain code, and the SATSCHIP shares the public part of its key, you can derive any payment address and confirm that it matches the address given by the card.

Effectively this means you know the XPUB, the card knows the XPRV, and it's easy to prove the two correspond.