34 lines
877 B
C
34 lines
877 B
C
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/*
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This file is for syndrome computation
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*/
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#include "synd.h"
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#include "params.h"
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#include "root.h"
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/* input: Goppa polynomial f, support L, received word r */
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/* output: out, the syndrome of length 2t */
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void PQCLEAN_MCELIECE460896F_CLEAN_synd(gf *out, gf *f, gf *L, const unsigned char *r) {
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int i, j;
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gf e, e_inv, c;
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for (j = 0; j < 2 * SYS_T; j++) {
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out[j] = 0;
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}
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for (i = 0; i < SYS_N; i++) {
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c = (r[i / 8] >> (i % 8)) & 1;
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e = PQCLEAN_MCELIECE460896F_CLEAN_eval(f, L[i]);
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e_inv = PQCLEAN_MCELIECE460896F_CLEAN_gf_inv(PQCLEAN_MCELIECE460896F_CLEAN_gf_mul(e, e));
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for (j = 0; j < 2 * SYS_T; j++) {
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out[j] = PQCLEAN_MCELIECE460896F_CLEAN_gf_add(out[j], PQCLEAN_MCELIECE460896F_CLEAN_gf_mul(e_inv, c));
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e_inv = PQCLEAN_MCELIECE460896F_CLEAN_gf_mul(e_inv, L[i]);
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}
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}
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}
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