Efficient Two-Step Protocol and Its Discriminative Feature Selections in Secure Similar Document Detection

Algorithm 5

Secure protocol for constructing a whole vector.

Protocol   SecureDF

   U is a set of -dimensional vector owned by Alice.

   V is a set of -dimensional vectors owned by Bob.

Alice:

   for each dimension do

     Compute = the number of occurrences in U;

   end-for

   Send to Bob;

Bob:

   for each dimension do

     Compute = the number of occurrences in V;

   end-for

   Send to Alice;

Alice and Bob:

   for each dimension do

  Compute ;  // = DF value of the th dimension

  end-for

Choose dimensions, , whose DF values of are larger than the other dimensions;