In many situations you cannot be forced to provide evidence that would be used against you or information which would lead to such evidence. I would go further and say that in all cases you shouldn't be required to provide such information.
It should be recognized as a basic right that you do not have to aid those who are trying to convict you of a crime. Our system of justice is adversarial for good reason and it is explicit in forcing those with the most power to limit the use of that power for the benefit of the accused. Without those checks and balances (and frequently even with them) abuse of that power, under the auspices of a greater good, would be common.