Document Coin uses a simple hash history algorithm to track coin provenance. Coin content is secured with cryptography but the history is secured with a hash of the cleartext content. We'll follow the JavaScript cryptography code line by line, using HTML5 Web Crypto APIs and IETF standardized JSON signature formats.

Coins also carry a copy of the signers public key which makes sybil attacks frictionless unless we take care which pubic keys we believe, so in a full implementation, identity will also be signed by subsequent coin holders, coloring the identity assertion with each transaction.

Expect slides with JSON on them, and JavaScript over-the-shoulder test/dev iterations using Prova in the browser.