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by flashdance
3268 days ago
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> If block creation intervals were lower it would compromise the security of the system and enable attacks with much less than 50% of the hash power. Not really. The odds of an attacker successfully generating a double-spending block remain the same with a lower block interval. Many alternative cryptocurrencies have far shorter blocktimes: Litecoin has 2.5min blocktimes, and ethereum is less than 30 seconds IIRC, and they don't have problems with rampant double spends. The problem with shorter blocktimes is that latency has a greater impact on mining profitability. A miner with a 600ms ping will lose ~0.1% of their revenue with a 10 minute blocktime, but will lose 2% of their revenue with a 30s blocktime. This gives miners an incentive to centralize geographically to reduce their latency. No bueno! |
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I based my statement on the following paper: Serialization of Proof-of-work Events: Confirming Transactions via Recursive Elections: https://eprint.iacr.org/2016/1159.pdf
Unfortunately, recent research has shown that the Nakamoto consensus has severe scalability limitations [6], [25], [11], [18]. Increasing the system’s throughput (either via an increase in block size or block creation rate) comes at the expense of security: Under high throughput, Nakamoto’s original guarantee no longer holds, and attackers with less than 50% of the computational power are able to disrupt the system. To avoid this, Bitcoin was set to operate at extremely low rates. The protocol enforces a slow block creation rate, and small block sizes, extending the blockchain only once every 10 minutes (in expectation) with a block containing up to 1 MB (roughly 2,000 transactions). Users must thus wait a long while to receive approval for their transfers.
Regarding litecoin: litecoin does have a lower block creation time of 2.5 minutes - however if you look at the average block size of litecoin it averages around 15kB, compared to ~950 kB of bitcoin (basically exhausting its 1MB limit): https://bitinfocharts.com/comparison/size-btc-ltc.html Considering the litecoin network operates way below its maximum capacity a double spending attack is indeed unlikely. However whether that security would hold up under full load remains to be seen.