Lecture 1.5: A Simple Cryptocurrency
Goofy coin
rules:
- Goofy can make a new coin whenever he wants, every coin made has a unique CoinID that Googy generated;
- Whoever owns a coin can pass it on to someone else by creating a statement (a data structure containing a statement and signed by the one who are spending the coin), and there is a hash pointer to the previous data structure.
- You can verify the validity of a coin by simply following the chain and verifying the signature along the way.
problems: double-spending attack
Scrooge coin
rules:
- Scrooge publishes a history of all transactions (a block chain, signed by Scrooge);
- Everyone can look into the block chain, and see that all of the transactions are valid and that every coin is consumed only once.
problems: Centralization