Suppose n companies (n 3) each make a bid on a project, but the value of each bi
ID: 3595770 • Letter: S
Question
Suppose n companies (n 3) each make a bid on a project, but the value of each bid is supposed to remain secret; i.e., each company knows its own bid, and nobody else is allowed to know it until all the bids are opened up together. Let the n bids be represented by positive integers b 1 , . . . , b n . We can assume that b 1 + . . . + b n < N for some known number N . Now suppose that all the companies want to know the average value (b 1 + . . . + b n )/n of the n bids. Devise a procedure (protocol) by which the n companies, among themselves, compute this average bids while keeping each bid secret; nobody else besides the n companies can participate in this protocol (no third party, etc.). Assume that in the exchange of information, only correct information is given (i.e., correct with respect to the agreed-upon protocol). [The answer is fairly short, but not obvious.]
Explanation / Answer
First one among the companies, for example b1 will generate a random number.
now company b1 will add that random number to their bid value and send it to b2(for not letting the company b2 to know the bid value of b1)
b2 will add their bid value and send it to b3.
this process will continue for bn companies.
now the first company b1 which generated a random number will subtract that random number from the total.
divide the total by n and we get the average bid value.