pqc/crypto_kem/ledakemlt52/leaktime/niederreiter.c
2019-06-16 17:01:29 +02:00

193 lines
8.0 KiB
C

#include "H_Q_matrices_generation.h"
#include "bf_decoding.h"
#include "dfr_test.h"
#include "gf2x_arith_mod_xPplusOne.h"
#include "niederreiter.h"
#include "qc_ldpc_parameters.h"
#include "rng.h"
#include <string.h>
void PQCLEAN_LEDAKEMLT52_LEAKTIME_niederreiter_keygen(publicKeyNiederreiter_t *pk, privateKeyNiederreiter_t *sk, AES_XOF_struct *keys_expander) {
POSITION_T HPosOnes[N0][DV]; // sequence of N0 circ block matrices (p x p): Hi
POSITION_T HtrPosOnes[N0][DV]; // Sparse tranposed circulant H
POSITION_T QPosOnes[N0][M]; // Sparse Q, Each row contains the position of the ones of all the blocks of a row of Q as exponent+P*block_position
POSITION_T LPosOnes[N0][DV * M];
POSITION_T auxPosOnes[DV * M];
unsigned char processedQOnes[N0];
DIGIT Ln0dense[NUM_DIGITS_GF2X_ELEMENT];
DIGIT Ln0Inv[NUM_DIGITS_GF2X_ELEMENT];
int is_L_full = 0;
uint8_t threshold = (DV * M) / 2 + 1; // threshold for round 2
sk->rejections = (int8_t) 0;
do {
PQCLEAN_LEDAKEMLT52_LEAKTIME_generateHPosOnes_HtrPosOnes(HPosOnes, HtrPosOnes, keys_expander);
PQCLEAN_LEDAKEMLT52_LEAKTIME_generateQsparse(QPosOnes, keys_expander);
for (int i = 0; i < N0; i++) {
for (int j = 0; j < DV * M; j++) {
LPosOnes[i][j] = INVALID_POS_VALUE;
}
}
memset(processedQOnes, 0x00, sizeof(processedQOnes));
for (int colQ = 0; colQ < N0; colQ++) {
for (int i = 0; i < N0; i++) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_sparse(DV * M, auxPosOnes,
DV, HPosOnes[i],
qBlockWeights[i][colQ], QPosOnes[i] + processedQOnes[i]);
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add_sparse(DV * M, LPosOnes[colQ],
DV * M, LPosOnes[colQ],
DV * M, auxPosOnes);
processedQOnes[i] += qBlockWeights[i][colQ];
}
}
is_L_full = 1;
for (int i = 0; i < N0; i++) {
is_L_full = is_L_full && (LPosOnes[i][DV * M - 1] != INVALID_POS_VALUE);
}
sk->rejections = sk->rejections + 1;
if (is_L_full) {
threshold = PQCLEAN_LEDAKEMLT52_LEAKTIME_DFR_test(LPosOnes);
}
} while (!is_L_full || threshold == DFR_TEST_FAIL);
sk->rejections = sk->rejections - 1;
sk->threshold = threshold;
memset(Ln0dense, 0x00, sizeof(Ln0dense));
for (int j = 0; j < DV * M; j++) {
if (LPosOnes[N0 - 1][j] != INVALID_POS_VALUE) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_set_coeff(Ln0dense, LPosOnes[N0 - 1][j], 1);
}
}
memset(Ln0Inv, 0x00, sizeof(Ln0Inv));
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_inverse(Ln0Inv, Ln0dense);
for (int i = 0; i < N0 - 1; i++) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_dense_to_sparse(pk->Mtr + i * NUM_DIGITS_GF2X_ELEMENT,
Ln0Inv,
LPosOnes[i],
DV * M);
}
for (int i = 0; i < N0 - 1; i++) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_transpose_in_place(pk->Mtr + i * NUM_DIGITS_GF2X_ELEMENT);
}
}
void PQCLEAN_LEDAKEMLT52_LEAKTIME_niederreiter_encrypt(DIGIT *syndrome, const publicKeyNiederreiter_t *pk, const DIGIT *err) {
int i;
DIGIT saux[NUM_DIGITS_GF2X_ELEMENT];
memset(syndrome, 0x00, NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
for (i = 0; i < N0 - 1; i++) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul(saux,
pk->Mtr + i * NUM_DIGITS_GF2X_ELEMENT,
err + i * NUM_DIGITS_GF2X_ELEMENT);
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add(syndrome, syndrome, saux);
}
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add(syndrome, syndrome, err + (N0 - 1)*NUM_DIGITS_GF2X_ELEMENT);
}
int PQCLEAN_LEDAKEMLT52_LEAKTIME_niederreiter_decrypt(DIGIT *err, const privateKeyNiederreiter_t *sk, const DIGIT *syndrome) {
AES_XOF_struct niederreiter_decrypt_expander;
POSITION_T HPosOnes[N0][DV];
POSITION_T HtrPosOnes[N0][DV];
POSITION_T QPosOnes[N0][M];
POSITION_T QtrPosOnes[N0][M];
POSITION_T auxPosOnes[DV * M];
POSITION_T LPosOnes[N0][DV * M];
POSITION_T auxSparse[DV * M];
POSITION_T Ln0trSparse[DV * M];
unsigned char processedQOnes[N0];
unsigned transposed_ones_idx[N0];
DIGIT privateSyndrome[NUM_DIGITS_GF2X_ELEMENT];
DIGIT mockup_error_vector[N0 * NUM_DIGITS_GF2X_ELEMENT];
int rejections = sk->rejections;
int currQoneIdx, endQblockIdx;
int decryptOk, err_weight;
PQCLEAN_LEDAKEMLT52_LEAKTIME_seedexpander_from_trng(&niederreiter_decrypt_expander, sk->prng_seed);
do {
PQCLEAN_LEDAKEMLT52_LEAKTIME_generateHPosOnes_HtrPosOnes(HPosOnes, HtrPosOnes, &niederreiter_decrypt_expander);
PQCLEAN_LEDAKEMLT52_LEAKTIME_generateQsparse(QPosOnes, &niederreiter_decrypt_expander);
for (int i = 0; i < N0; i++) {
for (int j = 0; j < DV * M; j++) {
LPosOnes[i][j] = INVALID_POS_VALUE;
}
}
memset(processedQOnes, 0x00, sizeof(processedQOnes));
for (int colQ = 0; colQ < N0; colQ++) {
for (int i = 0; i < N0; i++) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_sparse(DV * M, auxPosOnes,
DV, HPosOnes[i],
qBlockWeights[i][colQ], QPosOnes[i] + processedQOnes[i]);
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add_sparse(DV * M, LPosOnes[colQ],
DV * M, LPosOnes[colQ],
DV * M, auxPosOnes);
processedQOnes[i] += qBlockWeights[i][colQ];
}
}
rejections--;
} while (rejections >= 0);
memset(transposed_ones_idx, 0x00, sizeof(transposed_ones_idx));
for (unsigned source_row_idx = 0; source_row_idx < N0 ; source_row_idx++) {
currQoneIdx = 0; // position in the column of QtrPosOnes[][...]
endQblockIdx = 0;
for (int blockIdx = 0; blockIdx < N0; blockIdx++) {
endQblockIdx += qBlockWeights[source_row_idx][blockIdx];
for (; currQoneIdx < endQblockIdx; currQoneIdx++) {
QtrPosOnes[blockIdx][transposed_ones_idx[blockIdx]] = (P -
QPosOnes[source_row_idx][currQoneIdx]) % P;
transposed_ones_idx[blockIdx]++;
}
}
}
for (int i = 0; i < DV * M; i++) {
Ln0trSparse[i] = INVALID_POS_VALUE;
auxSparse[i] = INVALID_POS_VALUE;
}
for (int i = 0; i < N0; i++) {
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_sparse(DV * M, auxSparse,
DV, HPosOnes[i],
qBlockWeights[i][N0 - 1], &QPosOnes[i][ M - qBlockWeights[i][N0 - 1]]);
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add_sparse(DV * M, Ln0trSparse,
DV * M, Ln0trSparse,
DV * M, auxSparse);
}
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_transpose_in_place_sparse(DV * M, Ln0trSparse);
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_dense_to_sparse(privateSyndrome, syndrome, Ln0trSparse, DV * M);
/* prepare mockup error vector in case a decoding failure occurs */
memset(mockup_error_vector, 0x00, N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
memcpy(mockup_error_vector, syndrome, NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
PQCLEAN_LEDAKEMLT52_LEAKTIME_seedexpander(&niederreiter_decrypt_expander,
((unsigned char *) mockup_error_vector) + (NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B),
TRNG_BYTE_LENGTH);
memset(err, 0x00, N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
decryptOk = PQCLEAN_LEDAKEMLT52_LEAKTIME_bf_decoding(err, (const POSITION_T (*)[DV]) HtrPosOnes,
(const POSITION_T (*)[M]) QtrPosOnes, privateSyndrome, sk->threshold);
err_weight = 0;
for (int i = 0 ; i < N0; i++) {
err_weight += PQCLEAN_LEDAKEMLT52_LEAKTIME_population_count(err + (NUM_DIGITS_GF2X_ELEMENT * i));
}
decryptOk = decryptOk && (err_weight == NUM_ERRORS_T);
if (!decryptOk) { // TODO: not constant time, replace with cmov?
memcpy(err, mockup_error_vector, N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
}
return decryptOk;
}