| I have read the paper; unsurprisingly, it doesn't address any of the subsequent developments in the field. >> finding a less-efficient algorithm is a design goal The Bitcoin paper doesn't actually specify a specific algorithm at all, it just says "such as": > To implement a distributed timestamp server on a peer-to-peer basis, we will need to use a proof of-work system similar to Adam Back's Hashcash [6], rather than newspaper or Usenet posts. The proof-of-work involves scanning for a value that when hashed, such as with SHA-256, the hash begins with a number of zero bits. The Hashcash paper uses the term "minting". >>...in order to impose a global rate limit.. > To compensate for increasing hardware speed and varying interest in running nodes over time, the proof-of-work difficulty is determined by a moving average targeting an average number of blocks per hour. If they're generated too fast, the difficulty increases. ie to limit the global rate of block generation. Which is what makes it useful as a global distributed timestamp server. >> maximise the energy wasted > The steady addition of a constant of amount of new coins is analogous to gold miners expending
resources to add gold to circulation. In our case, it is CPU time and electricity that is expended. As everyone noticed fairly early on, like gold mining, this creates a means of expending energy to produce something which can be sold. Just as it's economically advantageous to burn down rainforest, it's economically advantageous to perform a trillion SHA operations and throw away the results of almost all of them. |