XCPCARD

Early bitcoin NFTs were not immutable.

In November 2015, XCPCARDS.com solved this for several cards, XCPCARD included.

This was achieved by including the following text in a bitcoin transaction:

xcpcards.com/XCPCARD 9k7Su12i

The identifier 9k7Su12i 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 XCPCARD one of the first real crypto cards!

Techincal Details

The file's full sha-256 hash in hex and base64 encodings:
f64ed2bb5da2a17242d77c35ea98f884411a131671de130d40dc45fbf6a92bd9
9k7Su12ioXJC13w16pj4hEEaExZx3hMNQNxF+/apK9k=

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.

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Full Set of Cards

The below cards were notarized by XCPCARDs.com

Most are from the Spells of Genesis project.

Click a card to view its details.