Andreas Antonopoulos: Nobody Pre-Empted The Idea Of ASIC Miners When Bitcoin Was Launching
Andreas Antonopoulos: Nobody Pre-empted the Idea of ASICs during Bitcoin’s Launch
In the latest Bitcoin Q&A episode on YouTube, Andreas Antonopoulos talked about why the nonce was small in the Bitcoin blockchain. The Bitcoin community uses the term ‘nonce' to refer to a 32-bit (4-byte) field whose value is adjusted by miners so that the hash of the block will be less than or equal to the current target of the network. The rests of the fields can’t be changed because they have a defined meaning.
Andreas, who has authored ‘Mastering of Bitcoin,' said that during the launch of Bitcoin, nobody thought of the idea of ASIC miners. He further explained that no one imagined that a particular technology (ASIC) would drive a lucrative industry, create a manufacturing sector and make people use silicon microchips to compete. Because of these reasons, the developers believed that 32 bits were sufficient.
As it turned out, 32 bits aren't enough. The difficulty of changing the block header format requires a hard fork. However, this hard fork would cause controversy, which is why the Bitcoin blockchain persists with 32 bits. Miners are therefore compelled to other platforms to find entropy.
Additionally, Andreas stated that not all positions in the header were equal. He further said that there was a specific oddity within the SHA-256 algorithm that permits an optimization called ASIC boost. This feature enables miners to calculate a midstate, which a practical measure if the SHA-256 of the header and lowers energy consumption by a significant 20%. Andreas said that most of this was completed by adjusting the Merkel tree in the block header as well as the Coinbase.
Andreas concluded by explaining that there were two types of ASIC boosts; covert and overt. Their use is dependent on the part of header a miner intends to change.