Files
MP-SPDZ/Auth/ShamirMC.hpp
2019-04-30 17:25:02 +10:00

56 lines
1.6 KiB
C++

/*
* ShamirMC.cpp
*
*/
#include "ShamirMC.h"
template<class T>
void ShamirMC<T>::POpen_Begin(vector<typename T::clear>& values,
const vector<T>& S, const Player& P)
{
(void) values;
os.clear();
os.resize(P.num_players());
bool send = P.my_num() <= threshold;
if (send)
{
for (auto& share : S)
share.pack(os[P.my_num()]);
}
for (int offset = 1; offset < P.num_players(); offset++)
{
int send_to = P.get_player(offset);
int receive_from = P.get_player(-offset);
bool receive = receive_from <= threshold;
if (send)
if (receive)
P.pass_around(os[P.my_num()], os[receive_from], offset);
else
P.send_to(send_to, os[P.my_num()], true);
else if (receive)
P.receive_player(receive_from, os[receive_from], true);
}
}
template<class T>
void ShamirMC<T>::POpen_End(vector<typename T::clear>& values,
const vector<T>& S, const Player& P)
{
(void) P;
int n_relevant_players = ShamirMachine::s().threshold + 1;
if (reconstruction.empty())
{
reconstruction.resize(n_relevant_players, 1);
for (int i = 0; i < n_relevant_players; i++)
reconstruction[i] = Shamir<typename T::clear>::get_rec_factor(i,
n_relevant_players);
}
values.clear();
values.resize(S.size());
for (size_t i = 0; i < values.size(); i++)
for (int j = 0; j < n_relevant_players; j++)
values[i] += os[j].template get<typename T::clear>() * reconstruction[j];
}