13#include <botan/mceliece.h>
15#include <botan/internal/code_based_util.h>
16#include <botan/internal/loadstor.h>
17#include <botan/internal/mce_internal.h>
18#include <botan/internal/polyn_gf2m.h>
24class binary_matrix final {
26 binary_matrix(
size_t m_rown,
size_t m_coln);
28 void row_xor(
size_t a,
size_t b);
34 uint32_t coef(
size_t i,
size_t j) {
return (m_elem[(i)*m_rwdcnt + (j) / 32] >> (j % 32)) & 1; }
36 void set_coef_to_one(
size_t i,
size_t j) {
37 m_elem[(i)*m_rwdcnt + (j) / 32] |= (
static_cast<uint32_t
>(1) << ((j) % 32));
40 void toggle_coeff(
size_t i,
size_t j) {
41 m_elem[(i)*m_rwdcnt + (j) / 32] ^= (
static_cast<uint32_t
>(1) << ((j) % 32));
44 size_t rows()
const {
return m_rown; }
46 size_t columns()
const {
return m_coln; }
48 const std::vector<uint32_t>& elem()
const {
return m_elem; }
54 std::vector<uint32_t> m_elem;
57binary_matrix::binary_matrix(
size_t rown,
size_t coln) : m_rown(rown), m_coln(coln), m_rwdcnt(1 + ((m_coln - 1) / 32)) {
58 m_elem = std::vector<uint32_t>(m_rown * m_rwdcnt);
61void binary_matrix::row_xor(
size_t a,
size_t b) {
62 for(
size_t i = 0; i != m_rwdcnt; i++) {
63 m_elem[a * m_rwdcnt + i] ^= m_elem[b * m_rwdcnt + i];
68secure_vector<size_t> binary_matrix::row_reduced_echelon_form() {
69 secure_vector<size_t> perm(m_coln);
70 for(
size_t i = 0; i != m_coln; i++) {
76 size_t max = m_coln - 1;
77 for(
size_t i = 0; i != m_rown; i++, max--) {
78 bool found_row =
false;
80 for(
size_t j = i; !found_row && j != m_rown; j++) {
81 if(coef(j, max) > 0) {
93 perm[m_coln - m_rown - 1 - failcnt] =
static_cast<int>(max);
100 perm[i + m_coln - m_rown] = max;
101 for(
size_t j = i + 1; j < m_rown; j++)
103 if(coef(j, max) > 0) {
109 for(
size_t j = i; j != 0; --j) {
110 if(coef(j - 1, max) > 0) {
119void randomize_support(std::vector<gf2m>& L, RandomNumberGenerator& rng) {
120 for(
size_t i = 0; i != L.size(); ++i) {
124 std::swap(L[i], L[rnd % L.size()]);
128std::unique_ptr<binary_matrix> generate_R(
129 std::vector<gf2m>& L, polyn_gf2m* g,
const GF2m_Field& sp_field,
size_t code_length,
size_t t) {
136 const size_t r = t * sp_field.get_extension_degree();
138 binary_matrix H(r, code_length);
140 for(
size_t i = 0; i != code_length; i++) {
142 x = sp_field.gf_inv(x);
144 for(
size_t j = 0; j < t; j++) {
145 for(
size_t k = 0; k < sp_field.get_extension_degree(); k++) {
146 if((y & (1 << k)) != 0) {
148 H.set_coef_to_one(j * sp_field.get_extension_degree() + k, i);
155 secure_vector<size_t> perm = H.row_reduced_echelon_form();
157 throw Invalid_State(
"McEliece keygen failed - could not bring matrix to row reduced echelon form");
160 auto result = std::make_unique<binary_matrix>(code_length - r, r);
161 for(
size_t i = 0; i < result->rows(); ++i) {
162 for(
size_t j = 0; j < result->columns(); ++j) {
163 if(H.coef(j, perm[i]) > 0) {
164 result->toggle_coeff(i, j);
169 std::vector<gf2m> Laux(code_length);
170 for(
size_t i = 0; i < code_length; ++i) {
171 Laux[i] = L[perm[i]];
174 for(
size_t i = 0; i < code_length; ++i) {
182 const size_t codimension = t * ext_deg;
184 if(code_length <= codimension) {
188 auto sp_field = std::make_shared<GF2m_Field>(ext_deg);
191 std::vector<gf2m> L(code_length);
193 for(
size_t i = 0; i != L.size(); i++) {
194 L[i] =
static_cast<gf2m>(i);
196 randomize_support(L, rng);
199 bool success =
false;
200 std::unique_ptr<binary_matrix> R;
208 R = generate_R(L, &g, *sp_field, code_length, t);
214 std::vector<polyn_gf2m> F =
syndrome_init(g, L,
static_cast<int>(code_length));
223 std::vector<uint32_t> H(co32 * code_length);
224 uint32_t* sk = H.data();
225 for(
size_t i = 0; i < code_length; ++i) {
226 for(
size_t l = 0; l < t; ++l) {
227 const size_t k = (l * ext_deg) / 32;
228 const size_t j = (l * ext_deg) % 32;
229 sk[k] ^=
static_cast<uint32_t
>(F[i].get_coef(l)) << j;
230 if(j + ext_deg > 32) {
232 sk[k + 1] ^= F[i].get_coef(l) >> (32 - j);
242 std::vector<gf2m> Linv(code_length);
243 for(
size_t i = 0; i != Linv.size(); ++i) {
244 Linv[L[i]] =
static_cast<gf2m>(i);
246 std::vector<uint8_t> pubmat(R->elem().size() * 4);
247 for(
size_t i = 0; i < R->elem().size(); i++) {
248 store_le(R->elem()[i], &pubmat[i * 4]);
static std::vector< polyn_gf2m > sqrt_mod_init(const polyn_gf2m &g)
gf2m lex_to_gray(gf2m lex)
std::vector< polyn_gf2m > syndrome_init(const polyn_gf2m &generator, const std::vector< gf2m > &support, int n)
McEliece_PrivateKey generate_mceliece_key(RandomNumberGenerator &rng, size_t ext_deg, size_t code_length, size_t t)
constexpr auto store_le(ParamTs &&... params)
gf2m random_gf2m(RandomNumberGenerator &rng)
std::vector< T, secure_allocator< T > > secure_vector
size_t bit_size_to_32bit_size(size_t bit_size)