Don't know what you are asking and due to your very vague statements, it seems that you may be trying to get one over on the government. Rarely works and the government does have the authority to seize assets, including those in safe deposit boxes, provided adequate procedures are followed. For a question like yours, I recommend that you do not post on a public website and strongly suggest that you retain private counsel to get answers to your questions.
Yes the IRS can freeze bank accounts for unpaid taxes. Yes other parts of the federal government can freeze bank accounts for suspicious activities. Yes, safe deposit boxes are separate from bank accounts. I suspect that if the IRS is aware that you have a safe deposit box it will order the bank to not allow you access to it. However, I have not yet heard of that happening.