532 lines
17 KiB
C
532 lines
17 KiB
C
#include "gf2x_arith_mod_xPplusOne.h"
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#include "rng.h"
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#include "sort.h"
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#include <string.h> // memcpy(...), memset(...)
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_copy(DIGIT dest[], const DIGIT in[]) {
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for (int i = NUM_DIGITS_GF2X_ELEMENT - 1; i >= 0; i--) {
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dest[i] = in[i];
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}
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}
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/* returns the coefficient of the x^exponent term as the LSB of a digit */
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DIGIT PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_get_coeff(const DIGIT poly[], unsigned int exponent) {
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unsigned int straightIdx = (NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_b - 1) - exponent;
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unsigned int digitIdx = straightIdx / DIGIT_SIZE_b;
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unsigned int inDigitIdx = straightIdx % DIGIT_SIZE_b;
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return (poly[digitIdx] >> (DIGIT_SIZE_b - 1 - inDigitIdx)) & ((DIGIT) 1) ;
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}
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/* sets the coefficient of the x^exponent term as the LSB of a digit */
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_set_coeff(DIGIT poly[], unsigned int exponent, DIGIT value) {
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unsigned int straightIdx = (NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_b - 1) - exponent;
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unsigned int digitIdx = straightIdx / DIGIT_SIZE_b;
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unsigned int inDigitIdx = straightIdx % DIGIT_SIZE_b;
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/* clear given coefficient */
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DIGIT mask = ~( ((DIGIT) 1) << (DIGIT_SIZE_b - 1 - inDigitIdx));
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poly[digitIdx] = poly[digitIdx] & mask;
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poly[digitIdx] = poly[digitIdx] | (( value & ((DIGIT) 1)) << (DIGIT_SIZE_b - 1 - inDigitIdx));
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}
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/* toggles (flips) the coefficient of the x^exponent term as the LSB of a digit */
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_toggle_coeff(DIGIT poly[], unsigned int exponent) {
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unsigned int straightIdx = (NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_b - 1) - exponent;
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unsigned int digitIdx = straightIdx / DIGIT_SIZE_b;
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unsigned int inDigitIdx = straightIdx % DIGIT_SIZE_b;
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/* clear given coefficient */
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DIGIT mask = ( ((DIGIT) 1) << (DIGIT_SIZE_b - 1 - inDigitIdx));
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poly[digitIdx] = poly[digitIdx] ^ mask;
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}
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/* population count for an unsigned 64-bit integer
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Source: Hacker's delight, p.66 */
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static int popcount_uint64t(uint64_t x) {
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x -= (x >> 1) & 0x5555555555555555;
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x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333);
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x = (x + (x >> 4)) & 0x0f0f0f0f0f0f0f0f;
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return (int)((x * 0x0101010101010101) >> 56);
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}
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/* population count for a single polynomial */
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int PQCLEAN_LEDAKEMLT52_LEAKTIME_population_count(DIGIT *poly) {
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int ret = 0;
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for (int i = NUM_DIGITS_GF2X_ELEMENT - 1; i >= 0; i--) {
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ret += popcount_uint64t(poly[i]);
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}
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return ret;
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}
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add(DIGIT Res[], const DIGIT A[], const DIGIT B[]) {
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PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_add(Res, A, B, NUM_DIGITS_GF2X_ELEMENT);
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}
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static void gf2x_mod(DIGIT out[], const DIGIT in[]) {
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DIGIT aux[NUM_DIGITS_GF2X_ELEMENT + 1];
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memcpy(aux, in, (NUM_DIGITS_GF2X_ELEMENT + 1)*DIGIT_SIZE_B);
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PQCLEAN_LEDAKEMLT52_LEAKTIME_right_bit_shift_n(NUM_DIGITS_GF2X_ELEMENT + 1, aux,
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MSb_POSITION_IN_MSB_DIGIT_OF_MODULUS);
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PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_add(out, aux + 1, in + NUM_DIGITS_GF2X_ELEMENT,
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NUM_DIGITS_GF2X_ELEMENT);
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out[0] &= ((DIGIT)1 << MSb_POSITION_IN_MSB_DIGIT_OF_MODULUS) - 1;
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}
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static void right_bit_shift(unsigned int length, DIGIT in[]) {
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unsigned int j;
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for (j = length - 1; j > 0 ; j--) {
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in[j] >>= 1;
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in[j] |= (in[j - 1] & (DIGIT)0x01) << (DIGIT_SIZE_b - 1);
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}
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in[j] >>= 1;
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}
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/* shifts by whole digits */
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static void left_DIGIT_shift_n(unsigned int length, DIGIT in[], unsigned int amount) {
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unsigned int j;
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for (j = 0; (j + amount) < length; j++) {
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in[j] = in[j + amount];
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}
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for (; j < length; j++) {
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in[j] = (DIGIT)0;
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}
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}
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/* may shift by an arbitrary amount*/
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static void left_bit_shift_wide_n(const int length, DIGIT in[], unsigned int amount) {
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left_DIGIT_shift_n(length, in, amount / DIGIT_SIZE_b);
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PQCLEAN_LEDAKEMLT52_LEAKTIME_left_bit_shift_n(length, in, amount % DIGIT_SIZE_b);
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}
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/* Hackers delight, reverses a uint64_t */
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static DIGIT reverse_digit(DIGIT x) {
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uint64_t t;
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x = (x << 31) | (x >> 33);
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t = (x ^ (x >> 20)) & 0x00000FFF800007FFLL;
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x = (t | (t << 20)) ^ x;
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t = (x ^ (x >> 8)) & 0x00F8000F80700807LL;
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x = (t | (t << 8)) ^ x;
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t = (x ^ (x >> 4)) & 0x0808708080807008LL;
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x = (t | (t << 4)) ^ x;
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t = (x ^ (x >> 2)) & 0x1111111111111111LL;
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x = (t | (t << 2)) ^ x;
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return x;
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}
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_transpose_in_place(DIGIT A[]) {
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/* it keeps the lsb in the same position and
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* inverts the sequence of the remaining bits */
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DIGIT mask = (DIGIT)0x1;
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DIGIT rev1, rev2, a00;
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int i, slack_bits_amount = NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_b - P;
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a00 = A[NUM_DIGITS_GF2X_ELEMENT - 1] & mask;
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right_bit_shift(NUM_DIGITS_GF2X_ELEMENT, A);
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for (i = NUM_DIGITS_GF2X_ELEMENT - 1; i >= (NUM_DIGITS_GF2X_ELEMENT + 1) / 2; i--) {
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rev1 = reverse_digit(A[i]);
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rev2 = reverse_digit(A[NUM_DIGITS_GF2X_ELEMENT - 1 - i]);
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A[i] = rev2;
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A[NUM_DIGITS_GF2X_ELEMENT - 1 - i] = rev1;
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}
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if (slack_bits_amount) {
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PQCLEAN_LEDAKEMLT52_LEAKTIME_right_bit_shift_n(NUM_DIGITS_GF2X_ELEMENT, A, slack_bits_amount);
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}
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A[NUM_DIGITS_GF2X_ELEMENT - 1] = (A[NUM_DIGITS_GF2X_ELEMENT - 1] & (~mask)) | a00;
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}
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static void rotate_bit_right(DIGIT in[]) { /* x^{-1} * in(x) mod x^P+1 */
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DIGIT rotated_bit = in[NUM_DIGITS_GF2X_ELEMENT - 1] & ((DIGIT)0x1);
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right_bit_shift(NUM_DIGITS_GF2X_ELEMENT, in);
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int msb_offset_in_digit = MSb_POSITION_IN_MSB_DIGIT_OF_MODULUS - 1;
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rotated_bit = rotated_bit << msb_offset_in_digit;
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in[0] |= rotated_bit;
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}
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/* cond swap: swaps digits A and B if swap_mask == -1 */
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static void gf2x_cswap(DIGIT *a, DIGIT *b, int swap_mask) {
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int i;
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DIGIT t;
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for (i = 0; i < NUM_DIGITS_GF2X_ELEMENT; i++) {
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t = swap_mask & (a[i] ^ b[i]);
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a[i] ^= t;
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b[i] ^= t;
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}
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}
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/* returns -1 mask if x != 0, otherwise 0 */
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static inline int nonzero(DIGIT x) {
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DIGIT t = x;
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t = -t;
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t >>= DIGIT_SIZE_b - 1;
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return -(int)t;
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}
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/* returns -1 mask if x < 0 else 0 */
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static inline int negative(int x) {
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uint32_t u = x;
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u >>= 31;
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return -(int)u;
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}
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/* return f(0) as digit */
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static inline DIGIT lsb(const DIGIT *p) {
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DIGIT mask = (DIGIT)1;
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return p[NUM_DIGITS_GF2X_ELEMENT - 1] & mask;
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}
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/* multiply poly with scalar and accumulate, expects s all-zero of all-one mask */
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static void gf2x_mult_scalar_acc(DIGIT *f, const DIGIT *g, const DIGIT s) {
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for (size_t i = 0; i < NUM_DIGITS_GF2X_ELEMENT; i++) {
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f[i] = f[i] ^ (s & g[i]);
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}
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}
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/* constant-time inverse, source: gcd.cr.yp.to */
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int PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_inverse(DIGIT out[], const DIGIT in[]) {
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int i, loop, swap, delta = 1;
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DIGIT g0_mask;
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DIGIT f[NUM_DIGITS_GF2X_MODULUS] = {0}; // f = x^P + 1
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DIGIT g[NUM_DIGITS_GF2X_ELEMENT]; // g = in
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DIGIT *v = out; // v = 0, save space
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DIGIT r[NUM_DIGITS_GF2X_ELEMENT] = {0}; // r = 1
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f[NUM_DIGITS_GF2X_MODULUS - 1] = 1;
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f[0] |= ((DIGIT)1 << MSb_POSITION_IN_MSB_DIGIT_OF_MODULUS);
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for (i = 0; i < NUM_DIGITS_GF2X_ELEMENT; i++) {
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g[i] = in[i];
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}
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for (i = 0; i < NUM_DIGITS_GF2X_ELEMENT; i++) {
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v[i] = 0;
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}
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r[NUM_DIGITS_GF2X_ELEMENT - 1] = 1;
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for (loop = 0; loop < 2 * P - 1; ++loop) {
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swap = negative(-delta) & nonzero(lsb(g)); // swap = -1 if -delta < 0 AND g(0) != 0
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delta ^= swap & (delta ^ -delta); // cond swap delta with -delta if swap
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delta++;
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gf2x_cswap(f, g, swap);
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gf2x_cswap(v, r, swap);
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g0_mask = -lsb(g);
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// g = (g - g0 * f) / x
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gf2x_mult_scalar_acc(g, f, g0_mask);
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right_bit_shift(NUM_DIGITS_GF2X_ELEMENT, g);
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// r = (r - g0 * v) / x
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gf2x_mult_scalar_acc(r, v, g0_mask);
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rotate_bit_right(r);
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}
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return nonzero(delta); // -1 if fail, 0 if success
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}
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul(DIGIT Res[], const DIGIT A[], const DIGIT B[]) {
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DIGIT aux[2 * NUM_DIGITS_GF2X_ELEMENT];
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PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mul(aux, A, B, NUM_DIGITS_GF2X_ELEMENT);
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gf2x_mod(Res, aux);
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}
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/*PRE: the representation of the sparse coefficients is sorted in increasing
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order of the coefficients themselves */
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_dense_to_sparse(DIGIT Res[], const DIGIT dense[],
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POSITION_T sparse[], unsigned int nPos) {
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DIGIT aux[2 * NUM_DIGITS_GF2X_ELEMENT] = {0x00};
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DIGIT resDouble[2 * NUM_DIGITS_GF2X_ELEMENT] = {0x00};
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memcpy(aux + NUM_DIGITS_GF2X_ELEMENT, dense, NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
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memcpy(resDouble + NUM_DIGITS_GF2X_ELEMENT, dense, NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
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if (sparse[0] != INVALID_POS_VALUE) {
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left_bit_shift_wide_n(2 * NUM_DIGITS_GF2X_ELEMENT, resDouble, sparse[0]);
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left_bit_shift_wide_n(2 * NUM_DIGITS_GF2X_ELEMENT, aux, sparse[0]);
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for (unsigned int i = 1; i < nPos; i++) {
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if (sparse[i] != INVALID_POS_VALUE) {
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left_bit_shift_wide_n(2 * NUM_DIGITS_GF2X_ELEMENT, aux, (sparse[i] - sparse[i - 1]) );
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PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_add(resDouble, aux, resDouble, 2 * NUM_DIGITS_GF2X_ELEMENT);
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}
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}
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}
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gf2x_mod(Res, resDouble);
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}
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_transpose_in_place_sparse(int sizeA, POSITION_T A[]) {
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POSITION_T t;
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int i = 0, j;
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if (A[i] == 0) {
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i = 1;
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}
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j = i;
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for (; i < sizeA && A[i] != INVALID_POS_VALUE; i++) {
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A[i] = P - A[i];
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}
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for (i -= 1; j < i; j++, i--) {
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t = A[j];
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A[j] = A[i];
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A[i] = t;
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}
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}
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_mul_sparse(size_t sizeR, POSITION_T Res[],
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size_t sizeA, const POSITION_T A[],
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size_t sizeB, const POSITION_T B[]) {
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POSITION_T prod;
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/* compute all the coefficients, filling invalid positions with P*/
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size_t lastFilledPos = 0;
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for (size_t i = 0 ; i < sizeA ; i++) {
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for (size_t j = 0 ; j < sizeB ; j++) {
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prod = A[i] + B[j];
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prod = ( (prod >= P) ? prod - P : prod);
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if ((A[i] != INVALID_POS_VALUE) &&
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(B[j] != INVALID_POS_VALUE)) {
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Res[lastFilledPos] = prod;
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} else {
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Res[lastFilledPos] = INVALID_POS_VALUE;
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}
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lastFilledPos++;
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}
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}
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while (lastFilledPos < sizeR) {
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Res[lastFilledPos] = INVALID_POS_VALUE;
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lastFilledPos++;
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}
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PQCLEAN_LEDAKEMLT52_LEAKTIME_uint32_sort(Res, sizeR);
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/* eliminate duplicates */
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POSITION_T lastReadPos = Res[0];
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size_t duplicateCount;
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size_t write_idx = 0;
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size_t read_idx = 0;
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while (read_idx < sizeR && Res[read_idx] != INVALID_POS_VALUE) {
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lastReadPos = Res[read_idx];
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read_idx++;
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duplicateCount = 1;
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while ( (Res[read_idx] == lastReadPos) && (Res[read_idx] != INVALID_POS_VALUE)) {
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read_idx++;
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duplicateCount++;
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}
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if (duplicateCount % 2) {
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Res[write_idx] = lastReadPos;
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write_idx++;
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}
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}
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/* fill remaining cells with INVALID_POS_VALUE */
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for (; write_idx < sizeR; write_idx++) {
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Res[write_idx] = INVALID_POS_VALUE;
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}
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}
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/* the implementation is safe even in case A or B alias with the result
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* PRE: A and B should be sorted, disjunct arrays ending with INVALID_POS_VALUE */
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_mod_add_sparse(
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int sizeR, POSITION_T Res[],
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int sizeA, const POSITION_T A[],
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int sizeB, const POSITION_T B[]) {
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POSITION_T tmpRes[DV * M];
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int idxA = 0, idxB = 0, idxR = 0;
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while ( idxA < sizeA &&
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idxB < sizeB &&
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A[idxA] != INVALID_POS_VALUE &&
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B[idxB] != INVALID_POS_VALUE ) {
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if (A[idxA] == B[idxB]) {
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idxA++;
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idxB++;
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} else {
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if (A[idxA] < B[idxB]) {
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tmpRes[idxR] = A[idxA];
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idxA++;
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} else {
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tmpRes[idxR] = B[idxB];
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idxB++;
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}
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idxR++;
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}
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}
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while (idxA < sizeA && A[idxA] != INVALID_POS_VALUE) {
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tmpRes[idxR] = A[idxA];
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idxA++;
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idxR++;
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}
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while (idxB < sizeB && B[idxB] != INVALID_POS_VALUE) {
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tmpRes[idxR] = B[idxB];
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idxB++;
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idxR++;
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}
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while (idxR < sizeR) {
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tmpRes[idxR] = INVALID_POS_VALUE;
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idxR++;
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}
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memcpy(Res, tmpRes, sizeof(POSITION_T)*sizeR);
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}
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/* Return a uniform random value in the range 0..n-1 inclusive,
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* applying a rejection sampling strategy and exploiting as a random source
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* the NIST seedexpander seeded with the proper key.
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* Assumes that the maximum value for the range n is 2^32-1
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*/
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static uint32_t rand_range(const unsigned int n, const int logn, AES_XOF_struct *seed_expander_ctx) {
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unsigned long required_rnd_bytes = (logn + 7) / 8;
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unsigned char rnd_char_buffer[4];
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uint32_t rnd_value;
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uint32_t mask = ( (uint32_t)1 << logn) - 1;
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do {
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PQCLEAN_LEDAKEMLT52_LEAKTIME_seedexpander(seed_expander_ctx, rnd_char_buffer, required_rnd_bytes);
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/* obtain an endianness independent representation of the generated random
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bytes into an unsigned integer */
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rnd_value = ((uint32_t)rnd_char_buffer[3] << 24) +
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((uint32_t)rnd_char_buffer[2] << 16) +
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((uint32_t)rnd_char_buffer[1] << 8) +
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((uint32_t)rnd_char_buffer[0] << 0) ;
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rnd_value = mask & rnd_value;
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} while (rnd_value >= n);
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return rnd_value;
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}
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/* Obtains fresh randomness and seed-expands it until all the required positions
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* for the '1's in the circulant block are obtained */
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void PQCLEAN_LEDAKEMLT52_LEAKTIME_rand_circulant_sparse_block(POSITION_T *pos_ones,
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int countOnes,
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AES_XOF_struct *seed_expander_ctx) {
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int duplicated, placedOnes = 0;
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uint32_t p;
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|
while (placedOnes < countOnes) {
|
|
p = rand_range(NUM_BITS_GF2X_ELEMENT,
|
|
P_BITS,
|
|
seed_expander_ctx);
|
|
duplicated = 0;
|
|
for (int j = 0; j < placedOnes; j++) {
|
|
if (pos_ones[j] == p) {
|
|
duplicated = 1;
|
|
}
|
|
}
|
|
if (duplicated == 0) {
|
|
pos_ones[placedOnes] = p;
|
|
placedOnes++;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Returns random weight-t circulant block */
|
|
void PQCLEAN_LEDAKEMLT52_LEAKTIME_rand_circulant_blocks_sequence(DIGIT sequence[N0 * NUM_DIGITS_GF2X_ELEMENT],
|
|
AES_XOF_struct *seed_expander_ctx) {
|
|
|
|
size_t polyIndex, duplicated, counter = 0;
|
|
POSITION_T p, exponent, rndPos[NUM_ERRORS_T];
|
|
|
|
memset(sequence, 0x00, N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
|
|
|
|
while (counter < NUM_ERRORS_T) {
|
|
p = rand_range(N0 * NUM_BITS_GF2X_ELEMENT, P_BITS, seed_expander_ctx);
|
|
duplicated = 0;
|
|
for (size_t j = 0; j < counter; j++) {
|
|
if (rndPos[j] == p) {
|
|
duplicated = 1;
|
|
}
|
|
}
|
|
if (duplicated == 0) {
|
|
rndPos[counter] = p;
|
|
counter++;
|
|
}
|
|
}
|
|
for (size_t j = 0; j < counter; j++) {
|
|
polyIndex = rndPos[j] / P;
|
|
exponent = rndPos[j] % P;
|
|
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_set_coeff( sequence + NUM_DIGITS_GF2X_ELEMENT * polyIndex, exponent,
|
|
( (DIGIT) 1));
|
|
}
|
|
|
|
}
|
|
|
|
|
|
void PQCLEAN_LEDAKEMLT52_LEAKTIME_rand_error_pos(POSITION_T errorPos[NUM_ERRORS_T],
|
|
AES_XOF_struct *seed_expander_ctx) {
|
|
|
|
int duplicated;
|
|
size_t counter = 0;
|
|
|
|
while (counter < NUM_ERRORS_T) {
|
|
POSITION_T p = rand_range(N0 * NUM_BITS_GF2X_ELEMENT, P_BITS, seed_expander_ctx);
|
|
duplicated = 0;
|
|
for (size_t j = 0; j < counter; j++) {
|
|
if (errorPos[j] == p) {
|
|
duplicated = 1;
|
|
}
|
|
}
|
|
if (duplicated == 0) {
|
|
errorPos[counter] = p;
|
|
counter++;
|
|
}
|
|
}
|
|
}
|
|
|
|
void PQCLEAN_LEDAKEMLT52_LEAKTIME_expand_error(DIGIT sequence[N0 * NUM_DIGITS_GF2X_ELEMENT],
|
|
const POSITION_T errorPos[NUM_ERRORS_T]) {
|
|
|
|
size_t polyIndex;
|
|
POSITION_T exponent;
|
|
|
|
memset(sequence, 0x00, N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
|
|
for (int j = 0; j < NUM_ERRORS_T; j++) {
|
|
polyIndex = errorPos[j] / P;
|
|
exponent = errorPos[j] % P;
|
|
PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_set_coeff( sequence + NUM_DIGITS_GF2X_ELEMENT * polyIndex, exponent,
|
|
( (DIGIT) 1));
|
|
}
|
|
}
|
|
|
|
|
|
void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_tobytes(uint8_t *bytes, const DIGIT *poly) {
|
|
size_t i, j;
|
|
for (i = 0; i < NUM_DIGITS_GF2X_ELEMENT; i++) {
|
|
for (j = 0; j < DIGIT_SIZE_B; j++) {
|
|
bytes[i * DIGIT_SIZE_B + j] = (uint8_t) (poly[i] >> 8 * j);
|
|
}
|
|
}
|
|
}
|
|
|
|
void PQCLEAN_LEDAKEMLT52_LEAKTIME_gf2x_frombytes(DIGIT *poly, const uint8_t *poly_bytes) {
|
|
size_t i, j;
|
|
for (i = 0; i < NUM_DIGITS_GF2X_ELEMENT; i++) {
|
|
poly[i] = (DIGIT) 0;
|
|
for (j = 0; j < DIGIT_SIZE_B; j++) {
|
|
poly[i] |= (DIGIT) poly_bytes[i * DIGIT_SIZE_B + j] << 8 * j;
|
|
}
|
|
}
|
|
}
|