Function preprocessing

ECDSA/preprocessing.hpp:34–114

template<template<class U> class T>
void preprocessing(vector<EcTuple<T>>& tuples, int buffer_size,
        T<P256Element::Scalar>& sk,
        SubProcessor<T<P256Element::Scalar>>& proc,
        EcdsaOptions opts)
{
    bool prep_mul = opts.prep_mul;
    if (prep_mul)
        proc.protocol.init_mul();

    Timer timer;
    timer.start();
    Player& P = proc.P;
    auto& prep = proc.DataF;
    size_t start = P.total_comm().sent;
    auto stats = P.total_comm();
    auto& extra_player = P;

    auto& protocol = proc.protocol;
    auto& MCp = proc.MC;
    typedef T<typename P256Element::Scalar> pShare;
    typedef T<P256Element> cShare;
    vector<pShare> inv_ks;
    vector<cShare> secret_Rs;
    prep.buffer_triples();
    vector<pShare> bs, cs;
    for (int i = 0; i < buffer_size; i++)
    {
        pShare a, b, c;
        prep.get_three(DATA_TRIPLE, a, b, c);
        inv_ks.push_back(a);
        bs.push_back(b);
        cs.push_back(c);
    }
    vector<P256Element::Scalar> cs_opened;
    MCp.POpen_Begin(cs_opened, cs, extra_player);
    if (opts.fewer_rounds)
        secret_Rs.insert(secret_Rs.begin(), bs.begin(), bs.end());
    else
    {
        MCp.POpen_End(cs_opened, cs, extra_player);
        for (int i = 0; i < buffer_size; i++)
            secret_Rs.push_back(bs[i] / cs_opened[i]);
    }
    vector<P256Element> opened_Rs(buffer_size);
    typename cShare::Direct_MC MCc(MCp.get_alphai());
    if (not opts.R_after_msg)
        MCc.POpen_Begin(opened_Rs, secret_Rs, extra_player);
    if (prep_mul)
    {
        for (int i = 0; i < buffer_size; i++)
            protocol.prepare_mul(inv_ks[i], sk);
        protocol.start_exchange();
    }
    if (opts.fewer_rounds)
        MCp.POpen_End(cs_opened, cs, extra_player);
    if (not opts.R_after_msg)
    {
        MCc.POpen_End(opened_Rs, secret_Rs, extra_player);