# Is this a secure multiparty protocol?

I am facing the following situation and i am trying to break down the problem into some specific cryptogrphic primitives. There is a function F that takes as input a bit string and produces a fingerprint.In my protocol there is a user $u$ who holds the input $D$ and $n$ other parties. I want the parties to compute $F(D)$ and all the parties to agree on that value. For example if $t$ out of $n$ where $t$ > $n/2$ agree on value $Y_1$ then the winner is $Y_1$. If there is no majority i want the protocol to run again. I want also secrecy at the results. I do not want the parties to learn the results and i want the parties to learn anything about the given input $D$. They will compute $F(D)$ without learning D. So they will receive an encrypted $E(D)$ and they will evalute $F(E(D))$ but only to evaluate the function. So my question is: Can we say that this is a secure multiparty computation ? Or it is a verifiable secret sharing?

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Wait... you say you "don't care about the confidentiality of inputs", but if I'm reading your description right, anyone who knows the function $F$ (which I'd normally assume to be public knowledge unless specified otherwise) and the input $D$ can obviously compute the output $F(D)$. So I must be missing something, but what? – Ilmari Karonen May 23 '12 at 20:13
my fault. I correct it. We do care about inputs. There are secret. i update the question with sth else. I want operation on encrypted data.Sorry i am thinking while i am writing – curious May 23 '12 at 20:19
"I do not want the parties to learn the results and i want the parties to learn anything about the given $\hspace{.2 in}$ input $D$." $\:$ How does either part of that sentence make sense? $\;\;$ – Ricky Demer May 24 '12 at 0:11