Early bitcoin NFTs were not immutable.
In November 2015, XCPCARDS.com solved this for several cards, XAJIBESAAR included.
This was achieved by including the following text in a bitcoin transaction:
xcpcards.com/XAJIBESAAR Uwntauug
The identifier Uwntauug is the jpeg's checksum which proves the card's design. Since this text is engraved on the blockchain, the proof can never be tampered with, nor can the timestamp be disputed.
This makes XAJIBESAAR one of the first real crypto cards!
The file's full sha-256 hash in hex and base64 encodings:5309ed6aeba000c45102f186faa4cbef87dc21bdc0a0264e4ebe667e703d2129
UwntauugAMRRAvGG+qTL74fcIb3AoCZOTr5mfnA9ISk=
The identifier is a 48 bit truncated hash.
This is sufficiently strong, yet short enough to have the text fit inside a Bitcoin op_return message.
The below cards were notarized by XCPCARDs.com
Most are from the Spells of Genesis project.
Click a card to view its details.