diff options
Diffstat (limited to 'crypto.c')
| -rw-r--r-- | crypto.c | 203 |
1 files changed, 161 insertions, 42 deletions
@@ -455,18 +455,11 @@ gcry_mpi_point_t ** smc_init2 (uint16_t size1, uint16_t size2) { gcry_mpi_point_t **ret; - gcry_mpi_point_t *data; - if (NULL == (ret = calloc (size1, sizeof (*ret) + size2 * sizeof (**ret)))) - { - weprintf ("could not alloc memory for 2 dimensional point array"); - return NULL; - } + ret = GNUNET_new_array_2d (size1, size2, gcry_mpi_point_t); - data = (gcry_mpi_point_t *)&ret[size1]; for (uint16_t i = 0; i < size1; i++) { - ret[i] = &data[i * size2]; for (uint16_t j = 0; j < size2; j++) { if (NULL == (ret[i][j] = gcry_mpi_point_new (0))) @@ -523,25 +516,13 @@ gcry_mpi_point_t *** smc_init3 (uint16_t size1, uint16_t size2, uint16_t size3) { gcry_mpi_point_t ***ret; - gcry_mpi_point_t **layer1; - gcry_mpi_point_t *layer2; - if (NULL == (ret = calloc (size1, sizeof (*ret) + - size2 * sizeof (**ret) + - size2 * size3 * sizeof (***ret)))) - { - weprintf ("could not alloc memory for 3 dimensional point array"); - return NULL; - } + ret = GNUNET_new_array_3d (size1, size2, size3, gcry_mpi_point_t); - layer1 = (gcry_mpi_point_t **)&ret[size1]; - layer2 = (gcry_mpi_point_t *)&layer1[size1 * size2]; for (uint16_t i = 0; i < size1; i++) { - ret[i] = &layer1[i * size2]; for (uint16_t j = 0; j < size2; j++) { - layer1[i * size2 + j] = &layer2[(i * size2 + j) * size3]; for (uint16_t k = 0; k < size3; k++) { if (NULL == (ret[i][j][k] = gcry_mpi_point_new (0))) @@ -1476,6 +1457,12 @@ fp_priv_prep_decryption (struct BRANDT_Auction *ad) ad->phi3 = smc_init3 (ad->n, ad->n, ad->k); brandt_assert (ad->phi3); + ad->phiproofs3 = GNUNET_new_array_3d (ad->n, + ad->n, + ad->k, + struct proof_2dle); + brandt_assert (ad->phiproofs3); + for (uint16_t i = 0; i < ad->n; i++) { for (uint16_t j = 0; j < ad->k; j++) @@ -1494,17 +1481,8 @@ fp_priv_prep_decryption (struct BRANDT_Auction *ad) } -/** - * fp_priv_decrypt_outcome decrypts the own shares of the outcome and packs them - * into a message buffer together with proofs of correctnes. - * - * @param[in] ad Pointer to the BRANDT_Auction struct to operate on - * @param[out] buflen Size of the returned message buffer in bytes - * @return A buffer containing the own share of the decrypted outcome - * which needs to be broadcast - */ -unsigned char * -fp_priv_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen) +static unsigned char * +fp_priv_decrypt_outcome_seller (struct BRANDT_Auction *ad, size_t *buflen) { unsigned char *ret; unsigned char *cur; @@ -1513,7 +1491,51 @@ fp_priv_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen) struct ec_mpi *phi; struct proof_2dle *proof2; - brandt_assert (ad && buflen); + *buflen = (sizeof (*head) + + (ad->n - 1) * ad->n * ad->k * (sizeof (*phi) + + sizeof (*proof2))); + ret = GNUNET_new_array (*buflen, unsigned char); + + head = (struct msg_head *)ret; + head->prot_version = htonl (0); + head->msg_type = htonl (msg_decrypt); + cur = ret + sizeof (*head); + + for (uint16_t h = 0; h < ad->n; h++) + { + for (uint16_t i = 0; i < ad->n; i++) + { + /* don't reveal outcome to losing bidders */ + if (h == i) + continue; + + for (uint16_t j = 0; j < ad->k; j++) + { + phi = (struct ec_mpi *)cur; + proof2 = (struct proof_2dle *)(cur + sizeof (*phi)); + + ec_point_serialize (phi, ad->phi3[h][i][j]); + memcpy (proof2, &ad->phiproofs3[h][i][j], sizeof (*proof2)); + + cur += sizeof (*phi) + sizeof (*proof2); + } + } + } + + gcry_mpi_point_release (tmp); + return ret; +} + + +static unsigned char * +fp_priv_decrypt_outcome_bidder (struct BRANDT_Auction *ad, size_t *buflen) +{ + unsigned char *ret; + unsigned char *cur; + struct msg_head *head; + gcry_mpi_point_t tmp = gcry_mpi_point_new (0); + struct ec_mpi *phi; + struct proof_2dle *proof2; *buflen = (sizeof (*head) + ad->n * ad->k * (sizeof (*phi) + sizeof (*proof2))); @@ -1552,22 +1574,42 @@ fp_priv_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen) } -int -fp_priv_recv_decryption (struct BRANDT_Auction *ad, - const unsigned char *buf, - size_t buflen, - uint16_t sender) +/** + * fp_priv_decrypt_outcome decrypts the own shares of the outcome and packs them + * into a message buffer together with proofs of correctnes. When this is called + * as the seller it will not decrypt anything, but just create the message + * buffer from all received decryption shares to broadcast back to all bidders. + * + * @param[in] ad Pointer to the BRANDT_Auction struct to operate on + * @param[out] buflen Size of the returned message buffer in bytes + * @return A buffer containing the share of the decrypted outcome + * which needs to be broadcast + */ +unsigned char * +fp_priv_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen) +{ + brandt_assert (ad && buflen); + if (ad->seller_mode) + return fp_priv_decrypt_outcome_seller (ad, buflen); + else + return fp_priv_decrypt_outcome_bidder (ad, buflen); +} + + +static int +fp_priv_recv_decryption_seller (struct BRANDT_Auction *ad, + const unsigned char *buf, + size_t buflen, + uint16_t sender) { int ret = 0; const unsigned char *cur = buf; struct proof_2dle *proof2; gcry_mpi_point_t phi = gcry_mpi_point_new (0); - brandt_assert (ad && buf); - if (buflen != (ad->n * ad->k * (sizeof (struct ec_mpi) + sizeof (*proof2)))) { - weprintf ("wrong size of received outcome decryption"); + weprintf ("wrong size of received outcome decryption from bidder"); goto quit; } @@ -1583,9 +1625,13 @@ fp_priv_recv_decryption (struct BRANDT_Auction *ad, ec_gen, proof2)) { - weprintf ("wrong zkp2 for phi, y received"); + weprintf ("wrong zkp2 for phi, y received from bidder"); goto quit; } + + /* store proof. we need to rebroadcast it to the other bidders */ + memcpy (&ad->phiproofs3[sender][i][j], proof2, sizeof (*proof2)); + ec_point_copy (ad->phi3[sender][i][j], phi); cur += sizeof (struct ec_mpi) + sizeof (*proof2); } @@ -1598,6 +1644,79 @@ quit: } +static int +fp_priv_recv_decryption_bidder (struct BRANDT_Auction *ad, + const unsigned char *buf, + size_t buflen, + uint16_t sender) +{ + int ret = 0; + const unsigned char *cur = buf; + struct proof_2dle *proof2; + gcry_mpi_point_t phi = gcry_mpi_point_new (0); + + if (buflen != ((ad->n - 1) * ad->n * ad->k * (sizeof (struct ec_mpi) + + sizeof (*proof2)))) + { + weprintf ("wrong size of received outcome decryption from seller"); + goto quit; + } + + for (uint16_t h = 0; h < ad->n; h++) + { + for (uint16_t i = 0; i < ad->n; i++) + { + /* those combinations are not sent by the seller */ + if (h == i) + continue; + + /* we already have our own phi values */ + if (h == ad->i) + { + cur += ad->k * (sizeof (struct ec_mpi) + sizeof (*proof2)); + continue; + } + + for (uint16_t j = 0; j < ad->k; j++) + { + ec_point_parse (phi, (struct ec_mpi *)cur); + proof2 = (struct proof_2dle *)(cur + sizeof (struct ec_mpi)); + if (smc_zkp_2dle_check (phi, + ad->y[h], + ad->phi3[h][i][j], + ec_gen, + proof2)) + { + weprintf ("wrong zkp2 for phi, y received from seller"); + goto quit; + } + ec_point_copy (ad->phi3[h][i][j], phi); + cur += sizeof (struct ec_mpi) + sizeof (*proof2); + } + } + } + + ret = 1; +quit: + gcry_mpi_point_release (phi); + return ret; +} + + +int +fp_priv_recv_decryption (struct BRANDT_Auction *ad, + const unsigned char *buf, + size_t buflen, + uint16_t sender) +{ + brandt_assert (ad && buf); + if (ad->seller_mode) + return fp_priv_recv_decryption_seller (ad, buf, buflen, sender); + else + return fp_priv_recv_decryption_bidder (ad, buf, buflen, sender); +} + + struct BRANDT_Result *fp_priv_determine_outcome (struct BRANDT_Auction *ad, uint16_t *len) { |