source: comparacioncriptosistemas/interfaz/polinomial.hpp

#include "polynomial.h"
//using namespace pol;



template <unsigned KEY_DEG>
void encrypt(File &in, FILE *out, const pol3v_t &D) {
        std::vector<u61_t> m;
        u61_t buf;
        u64_t size = 0, block_size;
        while (block_size = in.read(buf), block_size) {
                m.push_back(buf);
                size += block_size;
        }
        block512_t h = hash_nm::hash((char *)(m.data()), m.size() * sizeof(u61_t));
        fwrite(&h, sizeof(h), 1, out);
        u64_t max_deg = (m.size() - 1) / KEY_DEG + 2;
        pol3v_t f = XXX_get_f(max_deg, KEY_DEG);
        pol3v_t mes = XXX_get_mes(max_deg, KEY_DEG, size, m);
        (mes += f * D.get_same_rand_pol() + D * f.get_same_rand_pol()).write(out, TEXTPR);
        (mes += f * D.get_same_rand_pol() + D * f.get_same_rand_pol()).write(out, TEXTPR);
}

template <unsigned CLOSE_KEY_DEG, unsigned OPEN_KEY_DEG>
void decrypt(FILE *in, File &out, const pol_t &x, const pol_t &y) {
        block512_t h1, h2;
        fread(&h1, sizeof(h1), 1, in);
        pol3v_t tmp;
        tmp.read(in, TEXTPR);
        pol_t m, m1, fc, pol_x = get_x(), kxy = x * y;
        m1 = tmp.subst(x, y);
        tmp.read(in, TEXTPR);
        fc = tmp.subst(x, y) - m1;
        vector_t factor;
        fc.fact(CLOSE_KEY_DEG * OPEN_KEY_DEG * 2 + 1, factor);
        XXX_get_fact(factor, CLOSE_KEY_DEG * OPEN_KEY_DEG * 2 + 1, factor);
        std::vector<u61_t> res;
        u61_t a = x[CLOSE_KEY_DEG].inverse() * y[CLOSE_KEY_DEG].inverse();
        for (u32_t j = 0; j < factor.size(); ++j) {
            res.clear();
            m = m1 % (fc / factor[j]);
            u32_t deg = m.get_deg();
            u64_t size = m[deg] * a.pow(deg / (2 * CLOSE_KEY_DEG));
            m %= kxy.pow(deg / (2 * CLOSE_KEY_DEG)) * pol_x.pow(deg % (2 * CLOSE_KEY_DEG));
            deg = m.get_deg();
            for (u32_t i = 0; i <= deg; ++i) {
                res.push_back(m[deg - i] * a.pow((deg - i) / (2 * CLOSE_KEY_DEG)));
                m %= kxy.pow((deg - i) / (2 * CLOSE_KEY_DEG)) * pol_x.pow((deg - i) % (2 * CLOSE_KEY_DEG));
            }

            block512_t h2 = hash_nm::hash((char *)(res.data()), res.size() * sizeof(u61_t));

            // escritura del mensaje cifrado en el archivo de salida
            for (u32_t i = 0; i < res.size(); ++i) {
                if (size > MODSIZE - 1) {
                    size -= out.write(res[i]);
                }
                else {
                    size -= out.write(res[i], size);
                }
            }
            out.flush();
            break;
        }
}

template <unsigned CLOSE_KEY_DEG, unsigned OPEN_KEY_DEG>
   pol3v_t get_open_key(const pol_t &x, const pol_t &y) {
        polmap_t tmp;
        pol3v_t tmp2;
        for (u32_t i = 1; i <= OPEN_KEY_DEG; ++i) {
                tmp.insert(pol3v1_t(deg_t(i, i), get_rand_pol(2 * (OPEN_KEY_DEG - i) * CLOSE_KEY_DEG + 1, false)));
        }
        tmp.insert(pol3v1_t(deg_t(OPEN_KEY_DEG - 1, OPEN_KEY_DEG), get_rand_pol(1 + CLOSE_KEY_DEG, false)));
        tmp.insert(pol3v1_t(deg_t(OPEN_KEY_DEG, OPEN_KEY_DEG - 1), get_rand_pol(1 + CLOSE_KEY_DEG, false)));
        tmp.insert(pol3v1_t(deg_t(0, 1), get_rand_pol(CLOSE_KEY_DEG * (2 * OPEN_KEY_DEG - 1) + 1, false)));
        tmp.insert(pol3v1_t(deg_t(1, 0), get_rand_pol(CLOSE_KEY_DEG * (2 * OPEN_KEY_DEG - 1) + 1, false)));
        tmp2 = tmp;
    tmp.insert(pol3v1_t(deg_t(0, 0), pol_t() - tmp2.subst(x, y)));
        return tmp;
}