The biggest difference is that in forex there is a clear distinction between trading and "clearing." Trading occurs when two people agree to trade (SURPRISE!) a

The biggest difference is that in forex there is a clear distinction between trading and "clearing." Trading occurs when two people agree to trade (SURPRISE!) a specified amount of two (or more) currencies for a given rate of exchange at some point in the future. Clearing is the part where the money actually changes hands. You're probably asking yourself, "But what happens when someone agrees to a trade but the transaction doesn't clear?" This is referred to as counterparty risk. Counterparty risk is pretty self explanatory: the risk that the other person doesn't pay you. Therefore, compromising the exchange doesn't necessarily mean the end of the world since the "front office" (place where trading happens) is logically separated from the "back office" (place where money changes hands etc). As an aside, this is why France is in the process of regulating the movement of employees between the back office and the front office. If you are familiar with how both systems work then it becomes trivial to start hiding your trading activities and positions. The most damning part about compromising, say, a forex exchange, is that you get to take a peek at everyones trading history and hidden orders. So if you compromise the exchange and see that fund X has an open resting order for 20b EUR/USD @ some price you can then use this information to profit from. Or alternatively based upon the data you abscond with, it then becomes possible to reverse engineer their trading strategies. This is a bit different than a bitcoin exchange as my understanding is that the clearing and trading occur all at once and there is no separation. E.g. the exchange occurs as soon as the two parties agree. Although this eliminates counterparty risk it poses significant (insurmountable?) problems for the way automated trading currently works today. Another difference is that the vast majority of forex trading volume happens between institutional investors (usually on behalf of a corporate which is just trying to pay workers in another country) or other hedge funds. This makes security vastly easier since all of these servers are walled off from the public internet and the traffic they exchange never hits the public internet. Additionally it is also reasonable to expect that the system administrators of the end users understand how to operate a computer and keep it relatively secure :). Not always the case, but the assumption. Edit: Additionally, the clearing is handled by the counterparties themselves and not the exchange. With bitcoin the exchange handles everything and thus is the central point of failure.