void OTExtensionWithMatrix::extend_correlated(int nOTs_requested, BitVector& newReceiverInput)
{
// if (nOTs % nbaseOTs != 0)
// throw invalid_length(); //"nOTs must be a multiple of nbaseOTs\n");
if (nOTs_requested == 0)
return;
nOTs_requested = DIV_CEIL(nOTs_requested, 128) * 128;
// add k + s to account for discarding k OTs
int nOTs = nOTs_requested + 2 * 128;
int slice = nOTs / nsubloops / 128;
nOTs = slice * nsubloops * 128;
resize(nOTs);
newReceiverInput.resize(nOTs);
// randomize last 128 + 128 bits that will be discarded
for (int i = 0; i < 4; i++)
newReceiverInput.set_word(nOTs/64 - i - 1, G.get_word());
// subloop for first part to interleave communication with computation
for (int start = 0; start < nOTs / 128; start += slice)
{
expand<gf2n>(start, slice);
correlate<gf2n>(start, slice, newReceiverInput, true);
transpose(start, slice);
}
#ifdef OTEXT_TIMER
double elapsed;
#endif
// correlation check
if (!passive_only)
{
#ifdef OTEXT_TIMER
timeval startv, endv;
gettimeofday(&startv, NULL);
#endif
check_correlation(nOTs, newReceiverInput);
#ifdef OTEXT_TIMER
gettimeofday(&endv, NULL);
elapsed = timeval_diff(&startv, &endv);
cout << "\t\tTotal correlation check time: " << elapsed/1000000 << endl << flush;
times["Total correlation check"] += timeval_diff(&startv, &endv);
#endif
}
receiverOutputMatrix.resize(nOTs_requested);
senderOutputMatrices[0].resize(nOTs_requested);
senderOutputMatrices[1].resize(nOTs_requested);
newReceiverInput.resize(nOTs_requested);
}
void OTExtensionWithMatrix::transfer(int nOTs,
const BitVector& receiverInput)
{
#ifdef OTEXT_TIMER
timeval totalstartv, totalendv;
gettimeofday(&totalstartv, NULL);
#endif
cout << "\tDoing " << nOTs << " extended OTs as " << role_to_str(ot_role) << endl;
if (nOTs % nbaseOTs != 0)
throw invalid_length(); //"nOTs must be a multiple of nbaseOTs\n");
if (nOTs == 0)
return;
// add k + s to account for discarding k OTs
nOTs += 2 * 128;
int slice = nOTs / nsubloops / 128;
BitMatrix t1(nOTs), u(nOTs);
senderOutputMatrices.resize(2, BitMatrix(nOTs));
// resize to account for extra k OTs that are discarded
PRNG G;
G.ReSeed();
BitVector newReceiverInput(nOTs);
for (unsigned int i = 0; i < receiverInput.size_bytes(); i++)
{
newReceiverInput.set_byte(i, receiverInput.get_byte(i));
}
//BitVector newReceiverInput(receiverInput);
newReceiverInput.resize(nOTs);
receiverOutputMatrix.resize(nOTs);
for (int loop = 0; loop < nloops; loop++)
{
// randomize last 128 + 128 bits that will be discarded
for (int i = 0; i < 4; i++)
newReceiverInput.set_word(nOTs/64 - i, G.get_word());
// subloop for first part to interleave communication with computation
for (int start = 0; start < nOTs / 128; start += slice)
{
vector<octetStream> os(2);
BitMatrixSlice receiverOutputSlice(receiverOutputMatrix, start, slice);
BitMatrixSlice senderOutputSlices[2] = {
BitMatrixSlice(senderOutputMatrices[0], start, slice),
BitMatrixSlice(senderOutputMatrices[1], start, slice)
};
BitMatrixSlice t1Slice(t1, start, slice);
BitMatrixSlice uSlice(u, start, slice);
// expand with PRG and create correlation
if (ot_role & RECEIVER)
{
for (int i = 0; i < nbaseOTs; i++)
{
receiverOutputSlice.randomize(i, G_sender[i][0]);
t1Slice.randomize(i, G_sender[i][1]);
}
t1Slice ^= receiverOutputSlice;
t1Slice ^= newReceiverInput;
t1Slice.pack(os[0]);
// t1 = receiverOutputMatrix;
// t1 ^= newReceiverInput;
// receiverOutputMatrix.print_side_by_side(t1);
}
#ifdef OTEXT_TIMER
timeval commst1, commst2;
gettimeofday(&commst1, NULL);
#endif
// send t0 + t1 + x
send_if_ot_receiver(player, os, ot_role);
// sender adjusts using base receiver bits
if (ot_role & SENDER)
{
for (int i = 0; i < nbaseOTs; i++)
// randomize base receiver output
senderOutputSlices[0].randomize(i, G_receiver[i]);
// u = t0 + t1 + x
uSlice.unpack(os[1]);
senderOutputSlices[0].conditional_xor(baseReceiverInput, u);
}
#ifdef OTEXT_TIMER
gettimeofday(&commst2, NULL);
#ifdef VERBOSE
double commstime = timeval_diff(&commst1, &commst2);
cout << "\t\tCommunication took time " << commstime/1000000 << endl << flush;
#endif
times["Communication"] += timeval_diff(&commst1, &commst2);
#endif
// transpose t0[i] onto receiverOutput and tmp (q[i]) onto senderOutput[i][0]
#ifdef VERBOSE
cout << "Starting matrix transpose\n" << flush << endl;
#endif
#ifdef OTEXT_TIMER
timeval transt1, transt2;
gettimeofday(&transt1, NULL);
#endif
// transpose in 128-bit chunks
if (ot_role & RECEIVER)
receiverOutputSlice.transpose();
if (ot_role & SENDER)
senderOutputSlices[0].transpose();
#ifdef OTEXT_TIMER
gettimeofday(&transt2, NULL);
#ifdef VERBOSE
double transtime = timeval_diff(&transt1, &transt2);
cout << "\t\tMatrix transpose took time " << transtime/1000000 << endl << flush;
#endif
times["Matrix transpose"] += timeval_diff(&transt1, &transt2);
#endif
}
// correlation check
if (!passive_only)
{
#ifdef OTEXT_TIMER
timeval startv, endv;
gettimeofday(&startv, NULL);
#endif
check_correlation(nOTs, newReceiverInput);
#ifdef OTEXT_TIMER
gettimeofday(&endv, NULL);
#ifdef VERBOSE
double elapsed = timeval_diff(&startv, &endv);
cout << "\t\tTotal correlation check time: " << elapsed/1000000 << endl << flush;
#endif
times["Total correlation check"] += timeval_diff(&startv, &endv);
#endif
}
hash_outputs(nOTs);
#ifdef OTEXT_TIMER
#ifdef VERBOSE
gettimeofday(&totalendv, NULL);
double elapsed = timeval_diff(&totalstartv, &totalendv);
cout << "\t\tTotal thread time: " << elapsed/1000000 << endl << flush;
#endif
#endif
}
#ifdef OTEXT_TIMER
gettimeofday(&totalendv, NULL);
times["Total thread"] += timeval_diff(&totalstartv, &totalendv);
#endif
receiverOutputMatrix.resize(nOTs - 2 * 128);
senderOutputMatrices[0].resize(nOTs - 2 * 128);
senderOutputMatrices[1].resize(nOTs - 2 * 128);
}