If you give the same information as you have given to your employer (name, address, social, etc.), and they go looking for your account, they most definitely will find you.
When they find it, your brokerage is obligated to supply them with all of your information, including your transaction history if relevant.
If you did not tell them about it beforehand, the least they can do is terminate you, and they will most likely bring charges against you as well. If they win a court case against you where they believe insider trading was involved (to any degree) you will go to jail.
So the only way you can have a futures account while working at your firm is to have it in someone else's name, and trade it based on an agreement with that other person. But remember what I said about insider trading ... oh yeah, you will not only be putting yourself at risk, but the other person as well.
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So if you really want to trade futures that badly, just get another job.