They can do it without you knowing. They can do it without your knowing. Both ok?
Makes no difference?without us knowing is correct too?

Question

They can do it without you knowing. They can do it without your knowing. Both ok?
Makes no difference?without us knowing is correct too?

Answer

Colloquially, they are pretty much the same, but I see a difference.
I would use " ..without you knowing"
the alternative is "... without your knowledge"
So, if you combine the two, you can see how easy it is to confuse them!

Answer

Both are acceptable