# Are proof-of-work systems used by exchanges?

Are there any proof-of-work systems used by exchanges? If not, are there any interesting proposals worth reading?

In principle, there might be applications for proof-of-work systems in preventing algorithms from flooding exchanges either to manipulate prices or gain information, or perhaps to limit the advantages of physical proximity. An exchange might require a proof-of-work computation when withdrawing an order, for example, which makes placing and withdrawing a large number of orders unsafe.

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Connections to exchanges aren't public. The exchange knows who is sending the requests, even if they don't publicize it. Many exchanges (e.g. US futures) have messaging limits and penalize you if you violate them. – Joshua Ulrich Jan 29 '14 at 0:48