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Harcode curve in semi-internal modMult function

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Saves 80 bytes of code size.
This commit is contained in:
Manuel Pégourié-Gonnard 2019-11-04 12:12:00 +01:00
parent 3645ac93f5
commit c3ec14c87f
3 changed files with 31 additions and 36 deletions
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8
tinycrypt/ecc_dsa.c
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@ -257,7 +257,7 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
uECC_vli_modSub(z, sum, tx, curve->p, num_words); /* z = x2 - x1 */
XYcZ_add(tx, ty, sum, sum + num_words, curve);
uECC_vli_modInv(z, z, curve->p, num_words); /* z = 1/z */
apply_z(sum, sum + num_words, z, curve);
apply_z(sum, sum + num_words, z);
/* Use Shamir's trick to calculate u1*G + u2*Q */
points[0] = 0;
@ -283,15 +283,15 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
if (point) {
uECC_vli_set(tx, point, num_words);
uECC_vli_set(ty, point + num_words, num_words);
apply_z(tx, ty, z, curve);
apply_z(tx, ty, z);
uECC_vli_modSub(tz, rx, tx, curve->p, num_words); /* Z = x2 - x1 */
XYcZ_add(tx, ty, rx, ry, curve);
uECC_vli_modMult_fast(z, z, tz, curve);
uECC_vli_modMult_fast(z, z, tz);
}
}
uECC_vli_modInv(z, z, curve->p, num_words); /* Z = 1/Z */
apply_z(rx, ry, z, curve);
apply_z(rx, ry, z);
/* v = x1 (mod n) */
if (uECC_vli_cmp_unsafe(curve->n, rx, num_n_words) != 1) {