> Comments on the book > The restrictions on hash bits used by “hashcash” are just a variant of the “puzzles” that Ralph Merkle envisioned decades earlier; thi

> Comments on the book > The restrictions on hash bits used by “hashcash” are just a variant of the “puzzles” that Ralph Merkle envisioned decades earlier; this is not noted in the book. Merkle's puzzles (https://en.wikipedia.org/wiki/Merkle%27s_Puzzles https://en.wikipedia.org/wiki/Merkle%27s_Puzzles) aim to establish a shared key between 2 parties and involve breaking encryption with a short key by brute force. Hashcash involves finding inputs to a hash function, commiting to some message, whose output is below a target threshold, also by brute force. Similar in their brute force nature, but not a variant. > The current situation, where there are only a few giant mining pools that in a way act as mint, and a few trading sites that act as banks, is not mentioned. The pools have hundreds of individual independent contributors. > This has resulted in limiting privacy (because the network that exchanges transactions is small), and also in less democracy (because the mining network operators determine the code base). Miners have only limited influence over the code base. They cannot make any consensus changes. They can only enforce soft-forks that further restrict existing rules.