34 lines
870 B
C
34 lines
870 B
C
|
/*
|
||
|
|
This file is for syndrome computation
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "synd.h"
|
||
|
|
|
||
|
|
#include "params.h"
|
||
|
|
#include "root.h"
|
||
|
|
|
||
|
|
|
||
|
|
/* input: Goppa polynomial f, support L, received word r */
|
||
|
|
/* output: out, the syndrome of length 2t */
|
||
|
|
void PQCLEAN_MCELIECE460896_CLEAN_synd(gf *out, gf *f, gf *L, const unsigned char *r) {
|
||
|
|
int i, j;
|
||
|
|
gf e, e_inv, c;
|
||
|
|
|
||
|
|
for (j = 0; j < 2 * SYS_T; j++) {
|
||
|
|
out[j] = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
for (i = 0; i < SYS_N; i++) {
|
||
|
|
c = (r[i / 8] >> (i % 8)) & 1;
|
||
|
|
|
||
|
|
e = PQCLEAN_MCELIECE460896_CLEAN_eval(f, L[i]);
|
||
|
|
e_inv = PQCLEAN_MCELIECE460896_CLEAN_gf_inv(PQCLEAN_MCELIECE460896_CLEAN_gf_mul(e, e));
|
||
|
|
|
||
|
|
for (j = 0; j < 2 * SYS_T; j++) {
|
||
|
|
out[j] = PQCLEAN_MCELIECE460896_CLEAN_gf_add(out[j], PQCLEAN_MCELIECE460896_CLEAN_gf_mul(e_inv, c));
|
||
|
|
e_inv = PQCLEAN_MCELIECE460896_CLEAN_gf_mul(e_inv, L[i]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|