
Ask HN: Are small blockchains secure? - benp84
I finally read the Bitcoin white paper and there&#x27;s one thing I don&#x27;t get. The security relies on the majority of miners agreeing on the state of the global ledger, where &quot;the majority&quot; is measured in computing power.<p>It seems reasonable to assume that the computing power of a malicious miner doesn&#x27;t stand a chance against the enormous hashing power currently devoted to Bitcoin, but what about smaller blockchains? Couldn&#x27;t the biggest Bitcoin miner just switch all their resources to Litecoin for a few minutes and cause complete havoc? I imagine the smallest blockchains could be hacked&#x2F;ruined just by someone with a fairly high AWS Lambda rate limit.<p>I keep hearing about new projects to use blockchains for every little thing, and I just can&#x27;t imagine how any blockchain other than <i>the</i> big one can be secure.
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wmf
_Couldn 't the biggest Bitcoin miner just switch all their resources to
Litecoin for a few minutes and cause complete havoc?_

That particular case is not possible because Bitcoin and Litecoin require
different equipment to mine, so Bitcoin miners literally cannot mine Litecoin
at any speed. But when two different blockchains use the same mining equipment
it is possible for miners to switch chains at any time and thus a large miner
could perform a 51% attack against a small chain. So small blockchains are not
secure.

 _new projects to use blockchains for every little thing_

Most of these projects would be better off running on top of an existing
blockchain like Ethereum to avoid this problem.

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benp84
Thank you! That makes a lot of sense.

