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Comment by aakilfernandes | Hacker News Reader

Its amazing to me it took 15 years to go from hashcash to Bitcoin. I think it speaks to the strangeness of Bitcoin, and its niche idealogical underpinnings. Bitcoin solved a problem that most of the people never thought about. Yet if you're looking to solve Bitcoin's problem set, calibrated hashcash to secure a ledger seems completely obvious.

I also thought that Bitcoin's asic-vulnerability (and thus mining centralization) would be fatal. It turned out to be not fatal (yet), but thats not something which could be determined on paper. It needed real-world use before people knew if it could work or not.

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One of the points of the article is that the field wasn't idle during those 15 years; bit gold, b-money, and Finney's RPOW made incremental improvements on hashcash that led to Bitcoin.

Also, Bitcoin is kind of a "dirty" solution to the consensus problem; if all the academics were looking for an elegant solution it's not surprising that they didn't discover it.

I mentioned to an academic computer scientist that I worked with blockchains. He immediately asked "So these blockchains, how do they do consensus? Isn't it some kind of majority vote?" I said "Well, kind of, in combination with economic incentives to follow the longest chain." He just said "Well, come on! That's the whole problem! That's not a solution!" or something like that. Not impressed at all!

Bitcoin does not meet the requirements identified by the academic community for a usable digital currency. On the other hand, it works (while nothing that came out of academia in this area ever has). Infer from that what you will.

It would be nice if science had a term for its equivalent of "outsider art."

The repeated claim that Bitcoin came up with a totally new and unknown way of solving the problem always irks me.

Everyone keeping a complete history of all actions is, like, consensus 101.

Research is based around not having to do that.

That wasn't the key insight -- it was the idea that you could get a working solution under the assumption that 50%+1 of the hashing power is from honest nodes as long as those nodes agreed to coordinate on the ledger with the most proven work invested in it.

Hashcash was still missing a major piece: the idea of the blockchain as a solution to Byzantine fault tolerance.

Yes, this is the Satoshi idea. PoW to create consensus in an unpermissioned and open system.

"asic-vulnerability" is actually an asset. If Bitcoin were mined with CPUs or GPUs, any large organization or government could just point their computing power at Bitcoin and disrupt it.

Should I really explain why that doesn't make sense? With GPUs or CPUs individuals can outweigh large organizations. With ASICs, the 'many' are far less because the barrier to entry is so high, so the many can't easily outweigh the few and centralization occurs.

Don't be condescending. There are a couple more factors at play that make this more nuanced. First is that entering the ASIC field requires more time and economic outlay, so it's not something an attacker will do overnight. Also, it removes anonymity from an attacker as it's hard to hide the source of a large ASIC farm. Lastly, because of the investment in time and money, the existing well known players are not incentivized to turn their farms into attack vectors. I do recognize that the gov of China could force all miners there to do that, but I didn't claim that ASICs made BTC invulnerable, only that they are safer than CPU/GPU mining.

> it removes anonymity from an attacker as it's hard to hide the source of a large ASIC farm

This has already been shown to be untrue, an anonymous pool has mined both bitcoin cash and the segwit bitcoin chains.

CPU-, and to a certain extent, GPU-based mining is problematic because in the real world today all mining is concentrated in the hands of botnet operators.

That used to be a mounting problem in the Bitcoin world which began to fade away with the introduction of FPGA-based miners, but it's still a problem with a couple of altcoins. There are pros and cons with both compute-hard and memory-hard PoW but many seem to lean towards compute-hard being the less bad choice.

> all mining is concentrated in the hands of botnet operators

Do you have a source for this? I'm not even sure what CPU based currencies you are talking about. GPU based proof of work seems like even more of a stretch seeing as particular high end cards that are better with integers and bit shifting are usually used.

> any large organization or government

China is already well on their way to doing this, with Jihan Wu and the emergence of larger mining 'cartels'.

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