1 - Can any of the information that I provide on a tax return be used against me?

2 - Is there a law which forces me to provide the Government with information that it can use against me?

The Government answers the first question with every Form 1040 or other income tax related form it sends out. It's plainly stated in the Privacy Act Notice which is included. They can, and will.

The 2nd question they will NEVER answer. They can't.