add M+1st price private outcome implementation
This commit is contained in:
Markus Teich
parent
5d028cc81e
commit
5ce71329cf
@ -9,6 +9,7 @@ libbrandt_la_SOURCES = \
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crypto.c \
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fp_priv.c \
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fp_pub.c \
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mp_priv.c \
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util.c
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libbrandt_la_LIBADD = \
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22
crypto.h
22
crypto.h
@ -182,6 +182,12 @@ struct BRANDT_Result *fp_pub_determine_outcome (struct BRANDT_Auction *ad,
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uint16_t *len);
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void mp_priv_prep_outcome (struct BRANDT_Auction *ad);
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struct BRANDT_Result *mp_priv_determine_outcome (struct BRANDT_Auction *ad,
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uint16_t *len);
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/* --- Round dictionaries --- */
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typedef void
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@ -233,6 +239,8 @@ static const RoundPrep handler_prep[auction_last][outcome_last][msg_last] = {
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[outcome_private] = {
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[msg_init] = &smc_prep_keyshare,
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[msg_bid] = &smc_prep_bid,
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[msg_outcome] = &mp_priv_prep_outcome,
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[msg_decrypt] = &fp_priv_prep_decryption,
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},
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[outcome_public] = {
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[msg_init] = &smc_prep_keyshare,
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@ -271,6 +279,8 @@ static const MsgIn handler_in[auction_last][outcome_last][msg_last] = {
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[outcome_private] = {
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[msg_init] = &smc_recv_keyshare,
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[msg_bid] = &smc_recv_encrypted_bid,
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[msg_outcome] = &fp_priv_recv_outcome,
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[msg_decrypt] = &fp_priv_recv_decryption,
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},
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[outcome_public] = {
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[msg_init] = &smc_recv_keyshare,
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@ -310,6 +320,8 @@ static const MsgOut handler_out[auction_last][outcome_last][msg_last] = {
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[outcome_private] = {
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[msg_init] = &smc_gen_keyshare,
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[msg_bid] = &smc_encrypt_bid,
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[msg_outcome] = &fp_priv_compute_outcome,
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[msg_decrypt] = &fp_priv_decrypt_outcome,
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},
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[outcome_public] = {
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[msg_init] = &smc_gen_keyshare,
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@ -330,14 +342,14 @@ static const MsgOut handler_out[auction_last][outcome_last][msg_last] = {
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* of 0 means a private outcome, while a value of 1 means public outcome.
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*/
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static const Result handler_res[auction_last][outcome_last] = {
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[auction_firstPrice] = {
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[auction_firstPrice] = {
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[outcome_private] = &fp_priv_determine_outcome,
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[outcome_public] = &fp_pub_determine_outcome,
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},
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// [auction_mPlusFirstPrice] = {
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// [outcome_private] = ,
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// [outcome_public] = ,
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// },
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[auction_mPlusFirstPrice] = {
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[outcome_private] = &mp_priv_determine_outcome,
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// [outcome_public] = ,
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},
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};
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216
mp_priv.c
Normal file
216
mp_priv.c
Normal file
@ -0,0 +1,216 @@
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/* This file is part of libbrandt.
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* Copyright (C) 2016 GNUnet e.V.
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*
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* libbrandt is free software: you can redistribute it and/or modify it under
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* the terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libbrandt is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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* A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* libbrandt. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file mp_priv.c
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* @brief Implementation of the m+1st price private outcome algorithm.
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* @author Markus Teich
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*/
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#include "platform.h"
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#include <gcrypt.h>
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#include "crypto.h"
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#include "internals.h"
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#include "util.h"
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void
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mp_priv_prep_outcome (struct BRANDT_Auction *ad)
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{
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gcry_mpi_t factor = gcry_mpi_new (256);
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gcry_mpi_point_t subtr = gcry_mpi_point_new (0);
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gcry_mpi_point_t tmpa = gcry_mpi_point_new (0);
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gcry_mpi_point_t tmpb = gcry_mpi_point_new (0);
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gcry_mpi_point_t *tlta1;
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gcry_mpi_point_t *tltb1;
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gcry_mpi_point_t **tlta2;
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gcry_mpi_point_t **tltb2;
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gcry_mpi_point_t **tlta3;
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gcry_mpi_point_t **tltb3;
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ad->gamma3 = smc_init3 (ad->n, ad->n, ad->k);
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brandt_assert (ad->gamma3);
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ad->delta3 = smc_init3 (ad->n, ad->n, ad->k);
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brandt_assert (ad->delta3);
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/* create temporary lookup tables with partial sums */
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tlta1 = smc_init1 (ad->k);
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tltb1 = smc_init1 (ad->k);
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tlta2 = smc_init2 (ad->n, ad->k);
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tltb2 = smc_init2 (ad->n, ad->k);
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tlta3 = smc_init2 (ad->n, ad->k);
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tltb3 = smc_init2 (ad->n, ad->k);
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/* temporary lookup table for first summand (building ladder of bids) */
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for (uint16_t i = 0; i < ad->n; i++)
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{
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smc_sums_partial (tlta3[i], ad->alpha[i], ad->k, 1, 1);
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smc_sums_partial (tltb3[i], ad->beta[i], ad->k, 1, 1);
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for (uint16_t j = 0; j < ad->k; j++)
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{
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gcry_mpi_ec_sub (tlta2[i][j],
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tlta3[i][ad->k - 1],
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tlta3[i][j],
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ec_ctx);
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gcry_mpi_ec_sub (tltb2[i][j],
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tltb3[i][ad->k - 1],
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tltb3[i][j],
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ec_ctx);
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}
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brandt_assert (!ec_point_cmp (ec_zero, tlta2[i][ad->k - 1]));
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brandt_assert (!ec_point_cmp (ec_zero, tltb2[i][ad->k - 1]));
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}
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for (uint16_t j = 0; j < ad->k; j++)
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{
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/* 2L - 2I */
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smc_sum (tmpa, &tlta2[0][j], ad->n, ad->k);
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smc_sum (tmpb, &tltb2[0][j], ad->n, ad->k);
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gcry_mpi_ec_mul (tlta1[j], GCRYMPI_CONST_TWO, tmpa, ec_ctx);
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gcry_mpi_ec_mul (tltb1[j], GCRYMPI_CONST_TWO, tmpb, ec_ctx);
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/* I */
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smc_sum (tmpa, &ad->alpha[0][j], ad->n, ad->k);
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smc_sum (tmpb, &ad->beta[0][j], ad->n, ad->k);
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/* 2L - 2I + I = 2L - I */
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gcry_mpi_ec_add (tlta1[j], tlta1[j], tmpa, ec_ctx);
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gcry_mpi_ec_add (tltb1[j], tltb1[j], tmpb, ec_ctx);
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}
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/* This check only works directly after the loop when tmpa/tmpb are still
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* the sum of the last row */
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brandt_assert (!ec_point_cmp (tmpa, tlta1[ad->k - 1]));
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brandt_assert (!ec_point_cmp (tmpb, tltb1[ad->k - 1]));
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/* temporary lookup table for second summand (hide outcome from losers) */
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gcry_mpi_set_ui (factor, ad->m);
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gcry_mpi_lshift (factor, factor, 1);
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gcry_mpi_add_ui (factor, factor, 2);
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for (uint16_t i = 0; i < ad->n; i++)
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{
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for (uint16_t j = 0; j < ad->k; j++)
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{
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gcry_mpi_ec_mul (tlta2[i][j], factor, tlta3[i][j], ec_ctx);
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gcry_mpi_ec_mul (tltb2[i][j], factor, tltb3[i][j], ec_ctx);
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}
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}
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/* temporary lookup table for subtrahend (getting M+1st highest bid) */
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gcry_mpi_sub_ui (factor, factor, 1);
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gcry_mpi_ec_mul (subtr, factor, ec_gen, ec_ctx);
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/* compute gamma and delta */
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for (uint16_t i = 0; i < ad->n; i++)
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{
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for (uint16_t j = 0; j < ad->k; j++)
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{
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/* compute inner gamma */
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gcry_mpi_ec_add (tmpa, tlta1[j], tlta2[i][j], ec_ctx);
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gcry_mpi_ec_sub (tmpa, tmpa, subtr, ec_ctx);
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/* compute inner delta */
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gcry_mpi_ec_add (tmpb, tltb1[j], tltb2[i][j], ec_ctx);
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/* copy unmasked outcome to all other bidder layers so they don't
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* have to be recomputed to check the ZK proof_2dle's from other
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* bidders when receiving their outcome messages */
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for (uint16_t a = 0; a < ad->n; a++)
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{
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ec_point_copy (ad->gamma3[a][i][j], tmpa);
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ec_point_copy (ad->delta3[a][i][j], tmpb);
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}
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}
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}
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gcry_mpi_release (factor);
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gcry_mpi_point_release (subtr);
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gcry_mpi_point_release (tmpa);
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gcry_mpi_point_release (tmpb);
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smc_free1 (tlta1, ad->k);
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smc_free1 (tltb1, ad->k);
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smc_free2 (tlta2, ad->n, ad->k);
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smc_free2 (tltb2, ad->n, ad->k);
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smc_free2 (tlta3, ad->n, ad->k);
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smc_free2 (tltb3, ad->n, ad->k);
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}
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struct BRANDT_Result *
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mp_priv_determine_outcome (struct BRANDT_Auction *ad,
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uint16_t *len)
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{
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struct BRANDT_Result *ret;
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int32_t price = -1;
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uint16_t winners = 0;
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uint16_t max_winners;
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gcry_mpi_point_t sum_gamma = gcry_mpi_point_new (0);
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gcry_mpi_point_t sum_phi = gcry_mpi_point_new (0);
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brandt_assert (ad);
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max_winners = ad->seller_mode ? ad->m : 1;
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ret = GNUNET_new_array (max_winners, struct BRANDT_Result);
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for (uint16_t i = 0; i < ad->n; i++)
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{
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if (!ad->seller_mode && i != ad->i)
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continue;
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for (uint16_t j = 0; j < ad->k; j++)
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{
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smc_sum (sum_gamma, &ad->gamma3[0][i][j], ad->n, ad->n * ad->k);
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smc_sum (sum_phi, &ad->phi3[0][i][j], ad->n, ad->n * ad->k);
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gcry_mpi_ec_sub (sum_gamma, sum_gamma, sum_phi, ec_ctx);
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if (!ec_point_cmp (sum_gamma, ec_zero))
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{
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weprintf ("lol");
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if (winners >= max_winners)
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{
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weprintf ("too many winners detected");
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goto fail;
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}
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if (-1 != price && j != price)
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{
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weprintf ("multiple winning prices detected");
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goto fail;
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}
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price = j;
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ret[winners].bidder = i;
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ret[winners].price = j / ad->n;
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ret[winners].status = BRANDT_bidder_won;
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winners++;
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}
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}
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}
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gcry_mpi_point_release (sum_gamma);
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gcry_mpi_point_release (sum_phi);
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if (ad->m <= ad->n && winners < max_winners && -1 != price)
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weprintf ("too few winners detected");
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if (0 == winners)
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goto fail;
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if (len)
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*len = winners;
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return ret;
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fail:
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GNUNET_free (ret);
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return NULL;
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}
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