Method Create_More

FHEOffline/EncCommit.cpp:196–432

template<class T,class FD,class S>
void EncCommit<T,FD,S>::Create_More() const
{
  CODE_LOCATION
  const FHE_Params& params=(*pk).get_params();

  // Tweak by using p rather than p/2, as we do not center the ciphertexts
  int rhoi=(int) (6*params.get_R());
  bigint comm = active_mask(params.phi_m(), b, t);
  bigint Bound1=m[0].get_field().get_prime()*comm;
  bigint Bound2=comm;
  bigint Bound3=rhoi*comm;
  bigint UBound1=2*(Bound1-m[0].get_field().get_prime());
  bigint UBound2=2*(Bound2-1);
  bigint UBound3=2*(Bound3-rhoi);

  int my_num=(*P).my_num();
  /* First generate the good ciphertexts and messages for myself */
  PRNG G;
  G.ReSeed();
  vector<Random_Coins> rc(t,params);
  for (int i=0; i<t; i++)
    { m[i].randomize(G,cond);
      rc[i].generate(G);
      (*pk).encrypt(c[i][my_num],m[i],rc[i]);
    }

  // Broadcast and receive ciphertexts "c"
  vector< vector<octetStream> > ctx_c(t, vector<octetStream> ((*P).num_players()));
  for (int i=0; i<t; i++)
    { c[i][my_num].pack(ctx_c[i][my_num]);
      (*P).Broadcast_Receive(ctx_c[i]);
      for (int j=0; j<(*P).num_players(); j++)
	{ if (j!=my_num)
	    { c[i][j].unpack(ctx_c[i][j]); }
        }
    }

  vector< vector<octetStream> > seeds(2*TT, vector<octetStream>((*P).num_players()));
  vector< vector<octetStream> > Comm_seeds(2*TT,  vector<octetStream>((*P).num_players()));
  vector< octetStream > ctx_Delta((*P).num_players());
  Ciphertext ctx_C(params);
  vector<octetStream> Open_seeds(2*TT);
  vector<PRNG> Gseed(2*TT);
  vector<int> open(2*TT);
  vector<Rq_Element> z(4,Rq_Element(params.FFTD(),polynomial,polynomial));
  vector<octetStream> Comm_data((*P).num_players());

  char filename[1024];
  bool fail=true;
  int iter=0;
  while (fail && iter<M)
    { fail=false;
      // Now commit to seeds for the Delta's
      cout << "\t Create_More : iteration number = " << iter << endl;
      for (int i=0; i<2*TT; i++)
        { for (int j=0; j<(*P).num_players(); j++)
	    { seeds[i][j].reset_write_head(); 
	      Comm_seeds[i][j].reset_write_head();