Don't ever let it leave your hands.

FT

Even then it could not be safe. I once got a heads up from a computer dude that reckoned Metatrader can probably see the EA's if they want to. There's a lot of two ways comm's and we wouldn't know if it's copying and sending the EA's back to some server.

I don't want to start rumors, but it for total security you have to write and control all the software running on the computer you're using.

Personally I think MT is ok for learning and experimenting, but C++ and API's are the way to go if one ever gets beyond a few thousand bucks in the account.

I've heard about custom MT4's that allow EA peeking, I think it was FXPro (dont quote me on this) that modified their MT4 to do that. Most Market Maker brokers wont go to the trouble since 95% of people lose and if you're not scalping they can hedge the risk anyway. (and if you're scalping they'll kick you off) - They way the MM's get to see code is by holding contests that why I never submit. They're ran by brokers and you submit cleanly written source code!!

In my case my systems are actually several different Ea's and they all call external files. So not much of a chance anyone could get them to work...

There are several possible layers of protection, I will sort it from the worst to the best:

1. Compiled EA - useless, the EA can be easily decomplied with a 3rd party service for a minimal fee.

2. EA cobined with a dll - this is a better solution since all of the EA's logic is in the dll which is much harder to decompile, although not impossible (Take for example Microsoft or Apple who can't prevent their operating systems protections' from being cracked).

3. Remote hosting of the logic as Elkart suggested - this is one of the better protections possible, since there is nothing to decompile - the EA only receives buy/sell orders from a remote machine. This comes with a price though - latency. For scalping systems this would be a huge disatvantage since it's all about perfect timing.

4. Standalone execution - this would be the best solution, however it will cost accordingly. For each managed account you would need local access to the platform - either by having a MetaTrader open for each client on your own private machine, or access to the API of the broker used. This method of course also has some latency, but it's reduced to the minimum since lower latency can be achieved only if your machine is located in the same datacenter of the broker's.

Since the 4th soultion is not viable for most of the average EA creators, I would recommend using the 3rd solution if the EA is not sensitive to latency.