# Why do authors say conflicting things regarding leak-free stages in their paper?

In this paper the last sentence of the first paragraph in the abstract states:

We assume a (necessary) “leak-free” preprocessing stage.

But then later on in section 1.4 they say

Another interesting open question is to construct a leakage- resilient MPC protocol without assuming any leak-free stages,

Why do they say the leak-free stage is necessary but then later on they say it's an interesting open question ? When they say it's necessary doesn't that imply there is no open question (i.e. not debatable) ?

Is there any research done on leak-free stageS?

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The "'leak-free' preprocessing stage" is a necessary part of their MPC protocol. $\hspace{1.78 in}$ –  Ricky Demer Oct 29 '13 at 21:10
@RickyDemer - Yes - if it is necessary then why does it become and open question late on in the paper? I'm still unclear about this. –  user1068636 Oct 29 '13 at 22:28
I think they are saying assuming leak free is necessary to prove security for their protocol, but it woul be really cool (thus an open problem) to design a protocol that can tolerate leaks in any stage. –  mikeazo Oct 29 '13 at 23:19
@mikeazo - that makes sense to me. I guess there's no other explanation that makes sense so I'll mark it as correct if you answer the question. –  user1068636 Oct 29 '13 at 23:33