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finish/fix public first price auctions

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This commit is contained in:
Markus Teich 2016-08-02 16:55:00 +02:00
parent 6a4fa07b28
commit 017a90a88c
1 changed files with 20 additions and 7 deletions
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27
crypto.c
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@ -407,7 +407,9 @@ smc_free1 (gcry_mpi_point_t *dst, uint16_t size1)
/** /**
* smc_init1 creates a 1 dimensional array of curve points * smc_init1 creates a 1 dimensional array of curve points. Make sure to
* initialize the values before using them, they are not automatically set to
* the zero point!
* *
* @param[in] size1 size of the first dimension * @param[in] size1 size of the first dimension
* @return a pointer to the array or NULL on error. * @return a pointer to the array or NULL on error.
@ -460,7 +462,9 @@ smc_free2 (gcry_mpi_point_t **dst, uint16_t size1, uint16_t size2)
/** /**
* smc_init2 creates a 2 dimensional array of curve points * smc_init2 creates a 2 dimensional array of curve points. Make sure to
* initialize the values before using them, they are not automatically set to
* the zero point!
* *
* @param[in] size1 size of the first dimension * @param[in] size1 size of the first dimension
* @param[in] size2 size of the second dimension * @param[in] size2 size of the second dimension
@ -525,7 +529,9 @@ smc_free3 (gcry_mpi_point_t ***dst,
/** /**
* smc_init3 creates a 3 dimensional array of curve points * smc_init3 creates a 3 dimensional array of curve points. Make sure to
* initialize the values before using them, they are not automatically set to
* the zero point!
* *
* @param[in] size1 size of the first dimension * @param[in] size1 size of the first dimension
* @param[in] size2 size of the second dimension * @param[in] size2 size of the second dimension
@ -884,8 +890,15 @@ fp_pub_compute_outcome (struct BRANDT_Auction *ad, size_t *buflen)
brandt_assert (!ec_point_cmp (ec_zero, tlta1[ad->k - 1])); brandt_assert (!ec_point_cmp (ec_zero, tlta1[ad->k - 1]));
brandt_assert (!ec_point_cmp (ec_zero, tltb1[ad->k - 1])); brandt_assert (!ec_point_cmp (ec_zero, tltb1[ad->k - 1]));
/* temporarily store the \sum_{i=1}^n2^{i-1}b_i in tmp1, since it is needed /* initialize tmp array with zeroes, since we are calculating a sum */
* each time a gamma,delta pair is received from another bidder */ for (uint16_t j = 0; j < ad->k; j++)
{
ec_point_copy (ad->tmpa1[j], ec_zero);
ec_point_copy (ad->tmpb1[j], ec_zero);
}
/* store the \sum_{i=1}^n2^{i-1}b_i in tmp1 until outcome determination,
* since it is needed each time a gamma,delta pair is received from another
* bidder */
for (uint16_t i = 0; i < ad->n; i++) for (uint16_t i = 0; i < ad->n; i++)
{ {
for (uint16_t j = 0; j < ad->k; j++) for (uint16_t j = 0; j < ad->k; j++)
@ -895,7 +908,7 @@ fp_pub_compute_outcome (struct BRANDT_Auction *ad, size_t *buflen)
gcry_mpi_ec_mul (tmp, coeff, ad->beta[i][j], ec_ctx); gcry_mpi_ec_mul (tmp, coeff, ad->beta[i][j], ec_ctx);
gcry_mpi_ec_add (ad->tmpb1[j], ad->tmpb1[j], tmp, ec_ctx); gcry_mpi_ec_add (ad->tmpb1[j], ad->tmpb1[j], tmp, ec_ctx);
} }
gcry_mpi_mul_ui (coeff, coeff, 2); gcry_mpi_lshift (coeff, coeff, 1);
} }
for (uint16_t j = 0; j < ad->k; j++) for (uint16_t j = 0; j < ad->k; j++)
@ -1033,7 +1046,7 @@ fp_pub_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen)
phi = (struct ec_mpi *)cur; phi = (struct ec_mpi *)cur;
proof2 = (struct proof_2dle *)(cur + sizeof (*phi)); proof2 = (struct proof_2dle *)(cur + sizeof (*phi));
smc_sum (tmp, &ad->delta2[0][j], ad->n, ad->n * ad->k); smc_sum (tmp, &ad->delta2[0][j], ad->n, ad->k);
/* copy still encrypted outcome to all other bidder layers so they /* copy still encrypted outcome to all other bidder layers so they
* don't have to be recomputed to check the ZK proof_2dle's from * don't have to be recomputed to check the ZK proof_2dle's from