Do we have the moral right to lie?

Let’s say a technology gets developed that tracks what your eyes see / read on a computer.

Lets say then you go to court and you don’t want them to know what you read on the computer, because “not seeing it” would save the life of someone you love. Let’s say that without that technology there would be no way to prove that you saw it and you could walk away and your loved one would be safe.
But with the technology you’re caught and your loved one dies.

Is it morally wrong to take away someone’s reasonable chance to get away with a lie?

Would it fall under our reasonable right to privacy?