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by oska 3033 days ago
Most simple criticisms of why Bitcoin does things the way it does and then suggestions for simple ‘improvements’ such as yours (5 minute interval) tend to be naive and wrong. The 10 minute interval for Bitcoin transactions was chosen as the best tradeoff to balance pros and cons for making it shorter or longer.

Stackexchange has a good discussion on the topic:

https://bitcoin.stackexchange.com/questions/1863/why-was-the...
1 comments
dlubarov 3033 days ago
10 minutes was Satoshi's very rough guess at what a reasonable compromise might be. He didn't have any empirical data and probably didn't give it much thought. Since then we have some real data about propagation times, e.g. [1], and most other blockchains have chosen much faster block times, like ~12s for Ethereum.

[1] http://www.tik.ee.ethz.ch/file/49318d3f56c1d525aabf7fda78b23...

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jron 3032 days ago
Ethereum's security model is totally different: https://eprint.iacr.org/2016/555.pdf If you look at bitcoin based POW intervals, 10 minutes is very close to optimal: https://eprint.iacr.org/2015/1019.pdf
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dlubarov 3032 days ago
According to figure 2 in your second link, a blockchain with 1.5 rounds per block (or one block every ~19 seconds, based on their round length estimate) can withstand at least 40% hash power attacks. That seems like a reasonable tradeoff to me.

If you think 40% is not good enough, okay, let's target 48%. That's still just ~6.5 rounds per block (~82 seconds per block). Bitcoin's parameter of ~47 rounds per block is clearly overkill; the authors' graphs don't even go that far out (see figure 3).

Interestingly, the first paper you linked mentions that although Ethereum was intended to use single-level GHOST scoring, uncle blocks aren't actually counted toward chain difficulty, so it really has the same security model as Bitcoin. This was also confirmed by an Ethereum dev [1].

[1] https://ethereum.stackexchange.com/a/13750

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