Satscard

Satscards are cards which can be used to store bitcoin, inscriptions, and runes.

Slots

Each satscard has ten slots containing private keys with corresponding bitcoin addresses.

Initially, all slots are sealed and the private keys are stored only the satscard.

Slots can be unsealed, which allows the corresponding private key to be extracted.

Unsealing is permanent. If a satscard is sealed, you can have some confidence that private key is not known to anyone. That taking physical ownership of a satscard makes you the sole owner of assets in any sealed slots.

Lifespan

Satscards are expected to have a usable lifetime of ten years. Do not use satscards for long-term storage of valuable assets.

Viewing

When placed on a smartphone, the satscard transmits a URL, beginning with https://satscard.com/start or https://getsatscard.com/start, depending on when it was manufactured.

This URL contains a signature which can be used to recover the address of the current slot. This signature is made over a random nonce, so it changes every time the satscard is tapped, and provides some confidence that the satscard contains the private key.

ord supports viewing the contents of a satscard by entering the full URL into the ord explorer search bar, or the input field on the /satscard page.

For ordinals.com, this is ordinals.com/satscard.

Unsealing

Satscard slots can be unsealed and the private keys extracted using the cktap binary, available in the coinkite-tap-proto repository.

After a satscard slot is unsealed, all assets should be swept from that slot to another wallet, as the private key can now be read via NFC with the PIN.

Sweeping

First, clone the coinkite-tap-proto repository and install the cktap binary inside a Python virtual environment:

$ git clone https://github.com/coinkite/coinkite-tap-proto.git
$ cd coinkite-tap-proto
$ python3 -m venv venv
$ source venv/bin/activate
$ pip3 install 'coinkite-tap-protocol[cli]'

Unseal the satscard slot:

$ cktap unseal

Export the private key:

$ cktap wif

This will print something like:

Slot #1:

bc1q6e2renlnjyhwnyncd7sgr6s4s2cnkdknvrz40d

p2wpkh:KwVN7HkFnTymkfCh1b4Y5bRGftySuK4jjPQdgBoMURWCi8CjbZPN

Note the address type, in this case p2wpkh, and the private key, in this case KwVN7HkFnTymkfCh1b4Y5bRGftySuK4jjPQdgBoMURWCi8CjbZPN.

Write the private key to a file. This example will use the filename private-key.wif.

Now sweep the assets into your ord wallet:

$ cat private-key.wif | ord wallet sweep --address-type p2wpkh --fee-rate 10