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So if a new node join the game, it gets blockchain from other peers.
It may actually receive 2 different chains and it chooses the longer cos of more work done.
I wonder why isn't it simply choose the one that is being broadcast by higher number of peers instead of this mining madness??
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Because the cost of pretending to be many nodes is trivial. IP addresses are cheap, and anyone who controls your internet connection can pretend to be everyone.
However, mining is inherently expensive. You cannot fake hashpower.
And how about broadcast contains a proof of identity? Some trivial signature? – Djura Marinkov – 2017-08-18T21:08:14.053
Bitcoin has no trusted identities. If we did, there are much simpler constructions. – Pieter Wuille – 2017-08-18T21:09:33.527
@DjuraMarinkov All the known ways to do that at the time bitcoin was invented would have required a central authority to control which proofs of identity are acceptable. It's only later that schemes to do that kind of thing without such an authority were developed. And they have their own costs and tradeoffs. (Even if every single entity whose proof of identity anyone accepted were 100% trustworthy, they'd still need some complex scheme to ensure that they agree! "Valid chain with most work" is a simple scheme to ensure just that.) – David Schwartz – 2017-08-18T22:20:46.300
Well even with consensus how would you keep out mistakes? You still need an algorithm or rules. How would you know what majorities are real and what arent? I could say hey most people agree with me, how would you know? By votes, so just spam votes? How would you know 12000 ips didn't come from same single ip? All's you have to do is change ip header. – marshal craft – 2017-08-19T03:36:57.213
I'm not saying popular consensus isn't ever gonna work, but can you prove its security? Kinda like googles authyoath, they just tack on things like email, phone m, another email. Just ad hoc maner of cobbing the loop wholes with out mathematical tools, it has lead to hacking of millions of accounts. Elliptical curve, and others have quantifiable evidence and proofs, of their security based upon several assumptions or axioms. Till today they remain secure, and if anyone did find a loop whole, using it on hacking is a complete waist of the discovery, unlike stolen emails or phones. – marshal craft – 2017-08-19T03:42:56.287
Yes, thank you all (@marshalcraft, @PieterWuille, @DavidSwartz). I guess that software, bits and bytes can never be enough to prove such something, without including real world like hashpower and time consumption... – Djura Marinkov – 2017-08-19T07:49:14.077
I think you entirely miss the point. Physical things like phones and hash power don't make it secure. Its abstract principles of this universe which do. Prime numbers aren't a consequence of physical matter. They are an abstract principle. They subsume physical matter. Another example, abstract infinity. Often people argue if it physically exists, is the universe endless? But it doesn't matter because regardless of what physical nature does, we can consider if it does exist, and this it exists abstractly. So much so and so intertwined is abstract world that the study of the mere pissibility – marshal craft – 2017-08-19T12:14:36.203
Of boundless quantities, has allowed the abstract discovery of calculus which by coincidence governs the large scale physical world. – marshal craft – 2017-08-19T12:15:45.820