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cmp_protocol.c
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#include "common.h"
#include "cmp_protocol.h"
#include <openssl/sha.h>
#include <openssl/rand.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <semaphore.h>
#define ERR_STR "\nXXXXX ERROR XXXXX\n\n"
extern int PRINT_VALUES;
extern int PRINT_SECRETS;
/********************************************
*
* Auxiliary Functions
*
********************************************/
#define COMM_CHNL_PATTERN "CHANNEL_%lu_to_%lu_round_%lu.dat"
void cmp_comm_send_bytes(uint64_t my_index, uint64_t to_index, uint64_t round, const uint8_t *bytes, uint64_t byte_len)
{
char filename[sizeof(COMM_CHNL_PATTERN) + 8];
sprintf(filename, COMM_CHNL_PATTERN, my_index, to_index, round);
// Lock reader until finished sending/writing to file
sem_t* semptr = sem_open(filename, O_CREAT, 0644, 0);
int fd = open(filename, O_RDWR | O_CREAT, 0644);
write(fd, bytes, byte_len);
srand(time(0));
sleep(rand() % 5 + 1);
close(fd);
sem_post(semptr);
sem_close(semptr);
}
void cmp_comm_receive_bytes(uint64_t from_index, uint64_t my_index, uint64_t round, uint8_t *bytes, uint64_t byte_len)
{
char filename[sizeof(COMM_CHNL_PATTERN) + 8];
sprintf(filename, COMM_CHNL_PATTERN, from_index, my_index, round);
// Wait until file is written by sender
sem_t* semptr = sem_open(filename, O_CREAT, 0644, 0);
sem_wait(semptr);
int fd = open(filename, O_RDONLY, 0644);
read(fd, bytes, byte_len);
close(fd);
remove(filename);
sem_close(semptr);
sem_unlink(filename);
}
void cmp_void_to_bytes(uint8_t **to_bytes, const void *from_bytes, uint64_t byte_len, int move_to_end)
{
if ((!to_bytes) || (!*to_bytes) || (!from_bytes)) return;
memcpy(*to_bytes, from_bytes, byte_len);
if (move_to_end) *to_bytes += byte_len;
}
void cmp_void_from_bytes(void *to_bytes, uint8_t **from_bytes, uint64_t byte_len, int move_to_end)
{
if ((!from_bytes) || (!*from_bytes) || (!to_bytes)) return;
memcpy(to_bytes, *from_bytes, byte_len);
if (move_to_end) *from_bytes += byte_len;
}
void cmp_sample_bytes (uint8_t *rand_bytes, uint64_t byte_len)
{
RAND_bytes(rand_bytes, byte_len);
}
/********************************************
*
* Party Context for Protocol Execution
*
********************************************/
// Set sid hash from relevant existing party values (phases: 0/1/2 - init/keygen/refresh)
void cmp_set_sid_hash(cmp_party_t *party, int phase)
{
SHA512_CTX sha_ctx;
SHA512_Init(&sha_ctx);
SHA512_Update(&sha_ctx, party->sid, sizeof(hash_chunk));
if ((phase == 1) || (phase == 2))
{
SHA512_Update(&sha_ctx, party->srid, sizeof(hash_chunk));
}
uint8_t *temp_bytes = malloc(PAILLIER_MODULUS_BYTES); // Enough for uint64_t and group_element
group_elem_to_bytes(&temp_bytes, GROUP_ELEMENT_BYTES, party->ec_gen, party->ec, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
scalar_to_bytes(&temp_bytes,GROUP_ORDER_BYTES, party->ec_order, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ORDER_BYTES);
for (uint64_t i = 0; i < party->num_parties; ++i)
{
SHA512_Update(&sha_ctx, &party->parties_ids[i], sizeof(uint64_t));
if ((phase == 1) || (phase == 2))
{
group_elem_to_bytes(&temp_bytes, GROUP_ELEMENT_BYTES, party->public_X[i], party->ec, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
}
if (phase == 2)
{
scalar_to_bytes(&temp_bytes, PAILLIER_MODULUS_BYTES, party->paillier_pub[i]->N, 0);
SHA512_Update(&sha_ctx, temp_bytes, PAILLIER_MODULUS_BYTES);
scalar_to_bytes(&temp_bytes, RING_PED_MODULUS_BYTES, party->rped_pub[i]->N, 0);
SHA512_Update(&sha_ctx, temp_bytes, RING_PED_MODULUS_BYTES);
scalar_to_bytes(&temp_bytes, RING_PED_MODULUS_BYTES, party->rped_pub[i]->s, 0);
SHA512_Update(&sha_ctx, temp_bytes, RING_PED_MODULUS_BYTES);
scalar_to_bytes(&temp_bytes, RING_PED_MODULUS_BYTES, party->rped_pub[i]->t, 0);
SHA512_Update(&sha_ctx, temp_bytes, RING_PED_MODULUS_BYTES);
}
}
free(temp_bytes);
SHA512_Final(party->sid_hash, &sha_ctx);
}
cmp_party_t *cmp_party_new (uint64_t party_index, uint64_t num_parties, const uint64_t *parties_ids, const hash_chunk sid)
{
cmp_party_t *party = malloc(sizeof(cmp_party_t));
party->id = parties_ids[party_index];
party->index = party_index;
party->num_parties = num_parties;
party->parties_ids = calloc(num_parties, sizeof(uint64_t));
party->secret_x = scalar_new();
party->public_X = calloc(num_parties, sizeof(gr_elem_t));
party->paillier_priv = NULL;
party->paillier_pub = calloc(num_parties, sizeof(paillier_public_key_t *));
party->rped_pub = calloc(num_parties, sizeof(ring_pedersen_public_t *));
party->ec = ec_group_new();
party->ec_gen = ec_group_generator(party->ec);
party->ec_order = ec_group_order(party->ec);
party->R = group_elem_new(party->ec);
party->k = scalar_new();
party->chi = scalar_new();
memcpy(party->sid, sid, sizeof(hash_chunk));
party->paillier_priv = paillier_encryption_private_new();
for (uint64_t i = 0; i < num_parties; ++i)
{
party->parties_ids[i] = parties_ids[i];
party->public_X[i] = group_elem_new(party->ec);;
party->paillier_pub[i] = paillier_encryption_public_new();
party->rped_pub[i] = ring_pedersen_public_new();
}
cmp_set_sid_hash(party, 0);
party->key_generation_data = NULL;
party->refresh_data = NULL;
party->ecdsa_presign_data = NULL;
return party;
}
void cmp_party_free (cmp_party_t *party)
{
for (uint64_t i = 0; i < party->num_parties; ++i)
{
group_elem_free(party->public_X[i]);
paillier_encryption_free_keys(NULL, party->paillier_pub[i]);
ring_pedersen_free_param(NULL, party->rped_pub[i]);
}
paillier_encryption_free_keys(party->paillier_priv, NULL);
group_elem_free(party->R);
scalar_free(party->k);
scalar_free(party->chi);
scalar_free(party->secret_x);
ec_group_free(party->ec);
free(party->paillier_pub);
free(party->parties_ids);
free(party->rped_pub);
free(party->public_X);
free(party);
}
/***********************
*
* Key Generation
*
***********************/
void cmp_key_generation_init(cmp_party_t *party)
{
cmp_key_generation_data_t *kgd = malloc(sizeof(cmp_key_generation_data_t));
party->key_generation_data = kgd;
kgd->payload = calloc(party->num_parties, sizeof(cmp_key_generation_payload_t *));
for (uint64_t j = 0; j < party->num_parties; ++j)
{
kgd->payload[j] = malloc(sizeof(cmp_key_generation_payload_t));
kgd->payload[j]->commited_A = group_elem_new(party->ec);
kgd->payload[j]->public_X = group_elem_new(party->ec);
kgd->payload[j]->psi_sch = zkp_schnorr_new(party->ec);
}
kgd->secret_x = scalar_new();
kgd->tau = scalar_new();
// Point to values stored in payload (to be sent)
kgd->public_X = kgd->payload[party->index]->public_X;
kgd->commited_A = kgd->payload[party->index]->commited_A;
kgd->psi_sch = kgd->payload[party->index]->psi_sch;
kgd->srid = kgd->payload[party->index]->srid;
kgd->u = kgd->payload[party->index]->u;
kgd->V = kgd->payload[party->index]->V;
kgd->echo_broadcast = kgd->payload[party->index]->echo_broadcast;
kgd->run_time = 0;
}
void cmp_key_generation_clean(cmp_party_t *party)
{
cmp_key_generation_data_t *kgd = party->key_generation_data;
scalar_free(kgd->tau);
scalar_free(kgd->secret_x);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
zkp_schnorr_free(kgd->payload[j]->psi_sch);
group_elem_free(kgd->payload[j]->public_X);
group_elem_free(kgd->payload[j]->commited_A);
free(kgd->payload[j]);
}
free(kgd->payload);
free(kgd);
}
void cmp_key_generation_round_1_commit(hash_chunk commit_digest, const hash_chunk sid_hash, uint64_t party_id, const ec_group_t ec, const cmp_key_generation_payload_t *kg_payload)
{
uint8_t *temp_bytes = malloc(GROUP_ELEMENT_BYTES);
SHA512_CTX sha_ctx;
SHA512_Init(&sha_ctx);
SHA512_Update(&sha_ctx, sid_hash, sizeof(hash_chunk));
SHA512_Update(&sha_ctx, &party_id, sizeof(uint64_t));
SHA512_Update(&sha_ctx, kg_payload->srid, sizeof(hash_chunk));
group_elem_to_bytes(&temp_bytes, GROUP_ELEMENT_BYTES, kg_payload->public_X, ec, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
group_elem_to_bytes(&temp_bytes, GROUP_ELEMENT_BYTES, kg_payload->commited_A, ec, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
SHA512_Update(&sha_ctx, kg_payload->u, sizeof(hash_chunk));
SHA512_Final(commit_digest, &sha_ctx);
free(temp_bytes);
}
void cmp_key_generation_round_1_exec (cmp_party_t *party)
{
printf("### Round 1.\n");
clock_t time_start = clock();
uint64_t time_diff;
cmp_key_generation_data_t *kgd = party->key_generation_data;
scalar_sample_in_range(kgd->secret_x, party->ec_order, 0);
group_operation(kgd->public_X, NULL, party->ec_gen, kgd->secret_x, party->ec);
zkp_schnorr_public_t psi_sch_public;
psi_sch_public.G = party->ec;
psi_sch_public.g = party->ec_gen;
zkp_schnorr_commit(kgd->commited_A, kgd->tau, &psi_sch_public);
cmp_sample_bytes(kgd->srid, sizeof(hash_chunk));
cmp_sample_bytes(kgd->u, sizeof(hash_chunk));
cmp_key_generation_round_1_commit(kgd->V, party->sid, party->id, party->ec, kgd->payload[party->index]);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
kgd->run_time += time_diff;
// Send payload to parties
uint64_t send_bytes_len = sizeof(hash_chunk);
uint8_t *send_bytes = malloc(send_bytes_len);
uint8_t *curr_send = send_bytes;
cmp_void_to_bytes(&curr_send, kgd->V, sizeof(hash_chunk), 1);
assert(curr_send == send_bytes + send_bytes_len);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_send_bytes(party->index, j, 11, send_bytes, send_bytes_len);
}
free(send_bytes);
// Print
printf("### Broadcast (V_i).\t>>> %lu B, %lu ms\n", send_bytes_len, time_diff);
if (PRINT_VALUES)
{
printf("V_%lu = ", party->index); printHexBytes("0x", kgd->V, sizeof(hash_chunk), "\n", 0);
if (PRINT_SECRETS)
{
printf("x_%lu = ", party->index); printBIGNUM("", party->secret_x, "\n");
}
}
}
void cmp_key_generation_round_2_exec (cmp_party_t *party)
{
printf("### Round 2.\n");
cmp_key_generation_data_t *kgd = party->key_generation_data;
// Receive payloads from parties
uint64_t recv_bytes_len = sizeof(hash_chunk);
uint8_t *recv_bytes = malloc(recv_bytes_len);
uint8_t *curr_recv;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_receive_bytes(j, party->index, 11, recv_bytes, recv_bytes_len);
curr_recv = recv_bytes;
cmp_void_from_bytes(kgd->payload[j]->V, &curr_recv, sizeof(hash_chunk), 1);
assert(curr_recv == recv_bytes + recv_bytes_len);
}
free(recv_bytes);
// Execute
clock_t time_start = clock();
uint64_t time_diff;
// Echo broadcast - Send hash of all V_i commitments
SHA512_CTX sha_ctx;
SHA512_Init(&sha_ctx);
for (uint64_t i = 0; i < party->num_parties; ++i) SHA512_Update(&sha_ctx, kgd->payload[i]->V, sizeof(hash_chunk));
SHA512_Final(kgd->echo_broadcast, &sha_ctx);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
kgd->run_time += time_diff;
// Send payload to parties
uint64_t send_bytes_len = 3*sizeof(hash_chunk) + 2*GROUP_ELEMENT_BYTES;
uint8_t *send_bytes = malloc(send_bytes_len);
uint8_t *curr_send = send_bytes;
cmp_void_to_bytes(&curr_send, kgd->u, sizeof(hash_chunk), 1);
cmp_void_to_bytes(&curr_send, kgd->srid, sizeof(hash_chunk), 1);
cmp_void_to_bytes(&curr_send, kgd->echo_broadcast, sizeof(hash_chunk), 1);
group_elem_to_bytes(&curr_send, GROUP_ELEMENT_BYTES, kgd->public_X, party->ec, 1);
group_elem_to_bytes(&curr_send, GROUP_ELEMENT_BYTES, kgd->commited_A, party->ec, 1);
assert(curr_send == send_bytes + send_bytes_len);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_send_bytes(party->index, j, 12, send_bytes, send_bytes_len);
}
free(send_bytes);
// Print
printf("### Publish (srid_i, X_i, A_i, u_i, echo_broadcast_i).\t>>> %lu B, %lu ms\n", send_bytes_len, time_diff);
if (PRINT_VALUES)
{
printf("X_%lu = ", party->index); printECPOINT("", kgd->public_X, party->ec, "\n", 1);
printf("A_%lu = ", party->index); printECPOINT("", kgd->commited_A, party->ec, "\n", 1);
printf("srid_%lu = ", party->index); printHexBytes("0x", kgd->srid, sizeof(hash_chunk), "\n", 0);
printf("u_%lu = ", party->index); printHexBytes("0x", kgd->u, sizeof(hash_chunk), "\n", 0);
printf("echo_broadcast_%lu = ", party->index); printHexBytes("0x", kgd->echo_broadcast, sizeof(hash_chunk), "\n", 0);
}
}
void cmp_key_generation_round_3_exec (cmp_party_t *party)
{
printf("### Round 3.\n");
cmp_key_generation_data_t *kgd = party->key_generation_data;
// Receive payload from parties
uint64_t recv_bytes_len = 3*sizeof(hash_chunk) + 2*GROUP_ELEMENT_BYTES;
uint8_t *recv_bytes = malloc(recv_bytes_len);
uint8_t *curr_recv;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_receive_bytes(j, party->index, 12, recv_bytes, recv_bytes_len);
curr_recv = recv_bytes;
cmp_void_from_bytes(kgd->payload[j]->u, &curr_recv, sizeof(hash_chunk), 1);
cmp_void_from_bytes(kgd->payload[j]->srid, &curr_recv, sizeof(hash_chunk), 1);
cmp_void_from_bytes(kgd->payload[j]->echo_broadcast, &curr_recv, sizeof(hash_chunk), 1);
group_elem_from_bytes(kgd->payload[j]->public_X, &curr_recv, GROUP_ELEMENT_BYTES, party->ec, 1);
group_elem_from_bytes(kgd->payload[j]->commited_A, &curr_recv, GROUP_ELEMENT_BYTES, party->ec, 1);
assert(curr_recv == recv_bytes + recv_bytes_len);
}
free(recv_bytes);
// Execute round
clock_t time_start = clock();
uint64_t time_diff;
int *verified_decomm = calloc(party->num_parties, sizeof(int));
int *verified_echo = calloc(party->num_parties, sizeof(int));
hash_chunk ver_data;
memcpy(party->srid, kgd->srid, sizeof(hash_chunk));
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
// Verify commited V_i
cmp_key_generation_round_1_commit(ver_data, party->sid, party->parties_ids[j], party->ec, kgd->payload[j]);
verified_decomm[j] = memcmp(ver_data, kgd->payload[j]->V, sizeof(hash_chunk)) == 0;
// Verify echo broadcast of round 1 commitment -- ToDo: expand to identification of malicious party
verified_echo[j] = memcmp(kgd->echo_broadcast, kgd->payload[j]->echo_broadcast, sizeof(hash_chunk)) == 0;
// Set srid as xor of all party's srid_i
for (uint64_t pos = 0; pos < sizeof(hash_chunk); ++pos) party->srid[pos] ^= kgd->payload[j]->srid[pos];
}
// Verification log
for (uint64_t j = 0; j < party->num_parties; ++j){
if (j == party->index) continue;
if (verified_decomm[j] != 1) printf("%sParty %lu: decommitment of V_i from Party %lu\n",ERR_STR, party->index, j);
if (verified_echo[j] != 1) printf("%sParty %lu: received different echo broadcast of round 1 from Party %lu\n",ERR_STR, party->index, j);
}
free(verified_decomm);
free(verified_echo);
// Aux Info (ssid, i, srid)
zkp_aux_info_t *aux = zkp_aux_info_new(2*sizeof(hash_chunk) + sizeof(uint64_t), NULL);
uint64_t aux_pos = 0;
zkp_aux_info_update_move(aux, &aux_pos, party->sid_hash, sizeof(hash_chunk));
zkp_aux_info_update_move(aux, &aux_pos, &party->id, sizeof(uint64_t));
zkp_aux_info_update_move(aux, &aux_pos, party->srid, sizeof(hash_chunk));
assert(aux->info_len == aux_pos);
// Set Schnorr ZKP public claim and secret, then prove
zkp_schnorr_public_t psi_sch_public;
psi_sch_public.G = party->ec;
psi_sch_public.g = party->ec_gen;
psi_sch_public.X = kgd->public_X;
zkp_schnorr_secret_t psi_sch_secret;
psi_sch_secret.x = kgd->secret_x;
zkp_schnorr_prove(kgd->psi_sch, kgd->tau, &psi_sch_secret, &psi_sch_public, aux);
zkp_aux_info_free(aux);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
kgd->run_time += time_diff;
// Send payload to parties
uint64_t psi_sch_byte_len;
zkp_schnorr_proof_to_bytes(NULL, &psi_sch_byte_len, NULL, party->ec, 0);
uint64_t send_bytes_len = psi_sch_byte_len;
uint8_t *send_bytes = malloc(send_bytes_len);
uint8_t *curr_send = send_bytes;
zkp_schnorr_proof_to_bytes(&curr_send, &psi_sch_byte_len, kgd->psi_sch, party->ec, 1);
assert(curr_send == send_bytes + send_bytes_len);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_send_bytes(party->index, j, 13, send_bytes, send_bytes_len);
}
free(send_bytes);
// Print
printf("### Publish (psi_sch).\t>>> %lu B, %lu ms\n", send_bytes_len, time_diff);
if (PRINT_VALUES)
{
printf("# psi_i = ...\n");
printHexBytes("combined_srid = 0x", party->srid, sizeof(hash_chunk), "\n", 0);
}
}
void cmp_key_generation_final_exec(cmp_party_t *party)
{
printf("### KeyGen Finalization Round.\n");
cmp_key_generation_data_t *kgd = party->key_generation_data;
// Receive payload from parties
uint64_t psi_sch_byte_len;
zkp_schnorr_proof_from_bytes(NULL, NULL, &psi_sch_byte_len, party->ec, 0);
uint64_t recv_bytes_len = psi_sch_byte_len;
uint8_t *recv_bytes = malloc(recv_bytes_len);
uint8_t *curr_recv;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_receive_bytes(j, party->index, 13, recv_bytes, recv_bytes_len);
curr_recv = recv_bytes;
zkp_schnorr_proof_from_bytes(kgd->payload[j]->psi_sch, &curr_recv, &psi_sch_byte_len, party->ec, 1);
assert(curr_recv == recv_bytes + recv_bytes_len);
}
free(recv_bytes);
// Execute round
clock_t time_start = clock();
uint64_t time_diff;
int *verified_A = calloc(party->num_parties, sizeof(int));
int *verified_psi = calloc(party->num_parties, sizeof(int));
// Verify all Schnorr ZKP received from parties
// Aux Info (ssid, i, srid)
zkp_aux_info_t *aux = zkp_aux_info_new(2*sizeof(hash_chunk) + sizeof(uint64_t), NULL);
uint64_t aux_pos = 0;
zkp_aux_info_update_move(aux, &aux_pos, party->sid_hash, sizeof(hash_chunk));
zkp_aux_info_update_move(aux, &aux_pos, &party->id, sizeof(uint64_t)); // Changed for each party later
zkp_aux_info_update_move(aux, &aux_pos, party->srid, sizeof(hash_chunk));
assert(aux->info_len == aux_pos);
zkp_schnorr_public_t psi_sch_public_j;
psi_sch_public_j.G = party->ec;
psi_sch_public_j.g = party->ec_gen;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
verified_A[j] = group_elem_equal(kgd->payload[j]->psi_sch->A, kgd->payload[j]->commited_A, party->ec);
psi_sch_public_j.X = kgd->payload[j]->public_X;
zkp_aux_info_update(aux, sizeof(hash_chunk), &party->parties_ids[j], sizeof(uint64_t)); // Update i to commiting player
verified_psi[j] = zkp_schnorr_verify(kgd->payload[j]->psi_sch, &psi_sch_public_j, aux);
}
zkp_aux_info_free(aux);
// Verification log
for (uint64_t j = 0; j < party->num_parties; ++j){
if (j == party->index) continue;
if (verified_A[j] != 1) printf("%sParty %lu: schnorr zkp commited A (psi_sch.proof.A) different from previous round from Party %lu\n",ERR_STR, party->index, j);
if (verified_psi[j] != 1) printf("%sParty %lu: schnorr zkp (psi_sch) failed verification from Party %lu\n",ERR_STR, party->index, j);
}
free(verified_A);
free(verified_psi);
// Set party's values, and update sid_hash to include srid and public_X
scalar_copy(party->secret_x, kgd->secret_x);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
group_elem_copy(party->public_X[j], kgd->payload[j]->public_X);
}
// Update sid from updated relevant values
cmp_set_sid_hash(party, 1);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
kgd->run_time += time_diff;
// Print
printf("### Store (srid, all X, secret x_i).\t>>> %lu B, %lu ms\n",
sizeof(hash_chunk) + GROUP_ORDER_BYTES + party->num_parties * GROUP_ELEMENT_BYTES, time_diff);
}
/********************************************
*
* Key Refresh and Auxiliary Information
*
********************************************/
void cmp_refresh_aux_info_init(cmp_party_t *party)
{
cmp_refresh_data_t *reda = malloc(sizeof(cmp_refresh_data_t));
party->refresh_data = reda;
// Initialize payloads from other parties (and sent by self at my index)
reda->payload = calloc(party->num_parties, sizeof(cmp_refresh_payload_t*));
for (uint64_t j = 0; j < party->num_parties; ++j)
{
reda->payload[j] = malloc(sizeof(cmp_refresh_payload_t));
reda->payload[j]->paillier_pub = paillier_encryption_public_new();
reda->payload[j]->rped_pub = ring_pedersen_public_new();
reda->payload[j]->psi_mod = zkp_paillier_blum_new();
reda->payload[j]->psi_rped = zkp_ring_pedersen_param_new();
reda->payload[j]->psi_sch_k = calloc(party->num_parties, sizeof(zkp_schnorr_proof_t*));
reda->payload[j]->commited_A_k = calloc(party->num_parties, sizeof(gr_elem_t));
reda->payload[j]->encrypted_reshare_k = calloc(party->num_parties, sizeof(scalar_t));
reda->payload[j]->reshare_public_X_k = calloc(party->num_parties, sizeof(gr_elem_t));
for (uint64_t k = 0; k < party->num_parties; ++k)
{
reda->payload[j]->encrypted_reshare_k[k] = scalar_new();
reda->payload[j]->reshare_public_X_k[k] = group_elem_new(party->ec);
reda->payload[j]->commited_A_k[k] = group_elem_new(party->ec);
reda->payload[j]->psi_sch_k[k] = zkp_schnorr_new(party->ec);
}
}
// Init self vprivate values
reda->paillier_priv = paillier_encryption_private_new();
reda->rped_priv = ring_pedersen_private_new();
reda->reshare_secret_x_j = calloc(party->num_parties, sizeof(scalar_t));
reda->tau_j = calloc(party->num_parties, sizeof(scalar_t));
for (uint64_t j = 0; j < party->num_parties; ++j)
{
reda->reshare_secret_x_j[j] = scalar_new();
reda->tau_j[j] = scalar_new();
}
// Pointer to data stored at payload, but generated by self
reda->encrypted_reshare_j = reda->payload[party->index]->encrypted_reshare_k;
reda->reshare_public_X_j = reda->payload[party->index]->reshare_public_X_k;
reda->commited_A_j = reda->payload[party->index]->commited_A_k;
reda->paillier_pub = reda->payload[party->index]->paillier_pub;
reda->rped_pub = reda->payload[party->index]->rped_pub;
reda->psi_sch_j = reda->payload[party->index]->psi_sch_k;
reda->psi_mod = reda->payload[party->index]->psi_mod;
reda->psi_rped = reda->payload[party->index]->psi_rped;
reda->rho = reda->payload[party->index]->rho;
reda->u = reda->payload[party->index]->u;
reda->V = reda->payload[party->index]->V;
reda->echo_broadcast = reda->payload[party->index]->echo_broadcast;
reda->prime_time = 0;
reda->run_time = 0;
}
void cmp_refresh_aux_info_clean(cmp_party_t *party)
{
cmp_refresh_data_t *reda = party->refresh_data;
paillier_encryption_free_keys(reda->paillier_priv, NULL);
ring_pedersen_free_param(reda->rped_priv, NULL);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
scalar_free(reda->tau_j[j]);
scalar_free(reda->reshare_secret_x_j[j]);
}
free(reda->reshare_secret_x_j);
free(reda->tau_j);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
for (uint64_t k = 0; k < party->num_parties; ++k)
{
scalar_free(reda->payload[j]->encrypted_reshare_k[k]);
group_elem_free(reda->payload[j]->reshare_public_X_k[k]);
group_elem_free(reda->payload[j]->commited_A_k[k]);
zkp_schnorr_free(reda->payload[j]->psi_sch_k[k]);
}
paillier_encryption_free_keys(NULL, reda->payload[j]->paillier_pub);
ring_pedersen_free_param(NULL, reda->payload[j]->rped_pub);
zkp_paillier_blum_free(reda->payload[j]->psi_mod);
zkp_ring_pedersen_param_free(reda->payload[j]->psi_rped);
free(reda->payload[j]->psi_sch_k);
free(reda->payload[j]->commited_A_k);
free(reda->payload[j]->encrypted_reshare_k);
free(reda->payload[j]->reshare_public_X_k);
free(reda->payload[j]);
}
free(reda->payload);
free(reda);
}
void cmp_refresh_round_1_commit(hash_chunk commit_digest, const hash_chunk sid_hash, uint64_t party_id, uint64_t num_parties, const ec_group_t ec, const cmp_refresh_payload_t *re_payload)
{
uint8_t *temp_bytes = malloc(PAILLIER_MODULUS_BYTES); // Enough also for GROUP_ELEMENT_BYTES
SHA512_CTX sha_ctx;
SHA512_Init(&sha_ctx);
SHA512_Update(&sha_ctx, sid_hash, sizeof(hash_chunk));
SHA512_Update(&sha_ctx, &party_id, sizeof(uint64_t));
for (uint64_t k = 0; k < num_parties; ++k)
{
group_elem_to_bytes(&temp_bytes, GROUP_ELEMENT_BYTES, re_payload->reshare_public_X_k[k], ec, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
group_elem_to_bytes(&temp_bytes, GROUP_ELEMENT_BYTES, re_payload->commited_A_k[k], ec, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
}
scalar_to_bytes(&temp_bytes, PAILLIER_MODULUS_BYTES, re_payload->paillier_pub->N, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
scalar_to_bytes(&temp_bytes, PAILLIER_MODULUS_BYTES, re_payload->rped_pub->N, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
scalar_to_bytes(&temp_bytes, PAILLIER_MODULUS_BYTES, re_payload->rped_pub->s, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
scalar_to_bytes(&temp_bytes, PAILLIER_MODULUS_BYTES, re_payload->rped_pub->t, 0);
SHA512_Update(&sha_ctx, temp_bytes, GROUP_ELEMENT_BYTES);
SHA512_Update(&sha_ctx, re_payload->rho, sizeof(hash_chunk));
SHA512_Update(&sha_ctx, re_payload->u, sizeof(hash_chunk));
SHA512_Final(commit_digest, &sha_ctx);
free(temp_bytes);
}
void cmp_refresh_aux_info_round_1_exec (cmp_party_t *party)
{
printf("### Round 1.\n");
clock_t time_start = clock();
uint64_t time_diff;
cmp_refresh_data_t *reda = party->refresh_data;
paillier_encryption_generate_private(reda->paillier_priv, 4*PAILLIER_MODULUS_BYTES);
ring_pedersen_generate_private(reda->rped_priv, 4*RING_PED_MODULUS_BYTES);
paillier_encryption_copy_keys(NULL, reda->paillier_pub, reda->paillier_priv, NULL);
ring_pedersen_copy_param(NULL, reda->rped_pub, reda->rped_priv, NULL);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
reda->prime_time = time_diff;
time_start = clock();
// Sample other parties' reshares, set negative of sum for self
zkp_schnorr_public_t psi_sch_public_j;
psi_sch_public_j.G = party->ec;
psi_sch_public_j.g = party->ec_gen;
scalar_set_ul(reda->reshare_secret_x_j[party->index], 0);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
// Initialize relevant zkp
zkp_schnorr_commit(reda->commited_A_j[j], reda->tau_j[j], &psi_sch_public_j);
// Dont choose your own values
if (j == party->index) continue;
scalar_sample_in_range(reda->reshare_secret_x_j[j], party->ec_order, 0);
group_operation(reda->reshare_public_X_j[j], NULL, party->ec_gen, reda->reshare_secret_x_j[j], party->ec);
scalar_sub(reda->reshare_secret_x_j[party->index], reda->reshare_secret_x_j[party->index], reda->reshare_secret_x_j[j], party->ec_order);
}
group_operation(reda->reshare_public_X_j[party->index], NULL, party->ec_gen, reda->reshare_secret_x_j[party->index], party->ec);
cmp_sample_bytes(reda->rho, sizeof(hash_chunk));
cmp_sample_bytes(reda->u, sizeof(hash_chunk));
cmp_refresh_round_1_commit(reda->V, party->sid, party->id, party->num_parties, party->ec, reda->payload[party->index]);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
reda->run_time += time_diff;
// Send payload
uint64_t send_bytes_len = sizeof(hash_chunk);
uint8_t *send_bytes = malloc(send_bytes_len);
uint8_t *curr_send = send_bytes;
cmp_void_to_bytes(&curr_send, reda->V, sizeof(hash_chunk), 1);
assert(curr_send == send_bytes + send_bytes_len);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_send_bytes(party->index, j, 21, send_bytes, send_bytes_len);
}
free(send_bytes);
// Print
printf("### Broadcast (V_i).\t>>> %lu B, %lu ms (gen N_i) + %lu ms (rest)\n", send_bytes_len, reda->prime_time, time_diff);;
if (PRINT_VALUES)
{
printf("V_%lu = ", party->index); printHexBytes("0x", reda->V, sizeof(hash_chunk), "\n", 0);
if (!PRINT_SECRETS)
{
printf("paillier_p_%lu = ", party->index); printBIGNUM("", reda->paillier_priv->p, "\n");
printf("paillier_q_%lu = ", party->index); printBIGNUM("", reda->paillier_priv->q, "\n");
for (uint64_t j = 0; j < party->num_parties; ++j)
{
printf("x_%lue%lu = ", party->index, j); printBIGNUM("", reda->reshare_secret_x_j[j], "\n");
}
}
}
}
void cmp_refresh_aux_info_round_2_exec (cmp_party_t *party)
{
printf("### Round 2.\n");
cmp_refresh_data_t *reda = party->refresh_data;
// Receive payloads from parties
uint64_t recv_bytes_len = sizeof(hash_chunk);
uint8_t *recv_bytes = malloc(recv_bytes_len);
uint8_t *curr_recv;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_receive_bytes(j, party->index, 21, recv_bytes, recv_bytes_len);
curr_recv = recv_bytes;
cmp_void_from_bytes(reda->payload[j]->V, &curr_recv, sizeof(hash_chunk), 1);
assert(curr_recv == recv_bytes + recv_bytes_len);
}
free(recv_bytes);
// Execute Round
clock_t time_start = clock();
uint64_t time_diff;
// Echo broadcast - Hash of all V_i commitments
SHA512_CTX sha_ctx;
SHA512_Init(&sha_ctx);
for (uint64_t i = 0; i < party->num_parties; ++i) SHA512_Update(&sha_ctx, reda->payload[i]->V, sizeof(hash_chunk));
SHA512_Final(reda->echo_broadcast, &sha_ctx);
time_diff = (clock() - time_start) * 1000 /CLOCKS_PER_SEC;
reda->run_time += time_diff;
// Send payload
uint64_t paillier_bytelen;
uint64_t rped_bytelen;
paillier_public_to_bytes(NULL, &paillier_bytelen, NULL, PAILLIER_MODULUS_BYTES, 0);
ring_pedersen_public_to_bytes(NULL, &rped_bytelen, NULL, RING_PED_MODULUS_BYTES, 0);
uint64_t send_bytes_len = 3*sizeof(hash_chunk) + paillier_bytelen + rped_bytelen + 2*party->num_parties*GROUP_ELEMENT_BYTES;
uint8_t *send_bytes = malloc(send_bytes_len);
uint8_t *curr_send = send_bytes;
cmp_void_to_bytes(&curr_send, reda->u, sizeof(hash_chunk), 1);
cmp_void_to_bytes(&curr_send, reda->rho, sizeof(hash_chunk), 1);
cmp_void_to_bytes(&curr_send, reda->echo_broadcast, sizeof(hash_chunk), 1);
paillier_public_to_bytes(&curr_send, &paillier_bytelen, reda->paillier_pub, PAILLIER_MODULUS_BYTES, 1);
ring_pedersen_public_to_bytes(&curr_send, &rped_bytelen, reda->rped_pub, RING_PED_MODULUS_BYTES, 1);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
group_elem_to_bytes(&curr_send, GROUP_ELEMENT_BYTES, reda->reshare_public_X_j[j], party->ec, 1);
group_elem_to_bytes(&curr_send, GROUP_ELEMENT_BYTES, reda->commited_A_j[j], party->ec, 1);
}
assert(curr_send == send_bytes + send_bytes_len);
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_send_bytes(party->index, j, 22, send_bytes, send_bytes_len);
}
free(send_bytes);
// Print
printf("### Publish (X_i^{1...n}, A_i^{1...n}, Paillier N_i, Pedersen N_i, s_i, t_i, rho_i, u_i, echo_broadcast).\t>>> %lu B, %lu ms\n", send_bytes_len, time_diff);
if (PRINT_VALUES)
{
printf("echo_broadcast_%lu = ", party->index); printHexBytes("echo_broadcast = 0x", reda->echo_broadcast, sizeof(hash_chunk), "\n", 0);
printf("rho_%lu = ", party->index); printHexBytes("0x", reda->rho, sizeof(hash_chunk), "\n", 0);
printf("u_%lu = ", party->index); printHexBytes("0x", reda->u, sizeof(hash_chunk), "\n", 0);
printf("paillier_N_%lu = ", party->index); printBIGNUM("", reda->paillier_pub->N, "\n");
printf("rped_N_%lu = ", party->index); printBIGNUM("", reda->rped_pub->N, "\n");
printf("s_%lu = ", party->index); printBIGNUM("", reda->rped_pub->s, "\n");
printf("t_%lu = ", party->index); printBIGNUM("", reda->rped_pub->t, "\n");
for (uint64_t j = 0; j < party->num_parties; ++j)
{
printf("X_%lue%lu = ", party->index, j); printECPOINT("", reda->reshare_public_X_j[j], party->ec, "\n", 1);
printf("A_%lue%lu = ", party->index, j); printECPOINT("", reda->commited_A_j[j], party->ec, "\n", 1);
}
}
}
void cmp_refresh_aux_info_round_3_exec (cmp_party_t *party)
{
printf("### Round 3.\n");
cmp_refresh_data_t *reda = party->refresh_data;
// Receive payloads from parties
uint64_t paillier_bytelen;
uint64_t rped_bytelen;
paillier_public_to_bytes(NULL, &paillier_bytelen, NULL, PAILLIER_MODULUS_BYTES, 0);
ring_pedersen_public_to_bytes(NULL, &rped_bytelen, NULL, RING_PED_MODULUS_BYTES, 0);
uint64_t recv_bytes_len = 3*sizeof(hash_chunk) + paillier_bytelen + rped_bytelen + 2*party->num_parties*GROUP_ELEMENT_BYTES;
uint8_t *recv_bytes = malloc(recv_bytes_len);
uint8_t *curr_recv;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
cmp_comm_receive_bytes(j, party->index, 22, recv_bytes, recv_bytes_len);
curr_recv = recv_bytes;
cmp_void_from_bytes(reda->payload[j]->u, &curr_recv, sizeof(hash_chunk), 1);
cmp_void_from_bytes(reda->payload[j]->rho, &curr_recv, sizeof(hash_chunk), 1);
cmp_void_from_bytes(reda->payload[j]->echo_broadcast, &curr_recv, sizeof(hash_chunk), 1);
paillier_public_from_bytes(reda->payload[j]->paillier_pub, &curr_recv, &paillier_bytelen, PAILLIER_MODULUS_BYTES, 1);
ring_pedersen_public_from_bytes(reda->payload[j]->rped_pub, &curr_recv, &rped_bytelen, RING_PED_MODULUS_BYTES, 1);
for (uint64_t k = 0; k < party->num_parties; ++k)
{
group_elem_from_bytes(reda->payload[j]->reshare_public_X_k[k], &curr_recv, GROUP_ELEMENT_BYTES, party->ec, 1);
group_elem_from_bytes(reda->payload[j]->commited_A_k[k], &curr_recv, GROUP_ELEMENT_BYTES, party->ec, 1);
}
assert(curr_recv == recv_bytes + recv_bytes_len);
}
free(recv_bytes);
// Execute round
clock_t time_start = clock();
uint64_t time_diff;
gr_elem_t combined_public = group_elem_new(party->ec);
// Verification
int *verified_modulus_size = calloc(party->num_parties, sizeof(int));
int *verified_public_shares = calloc(party->num_parties, sizeof(int));
int *verified_decomm = calloc(party->num_parties, sizeof(int));
int *verified_echo = calloc(party->num_parties, sizeof(int));
hash_chunk ver_data;
for (uint64_t j = 0; j < party->num_parties; ++j)
{
if (j == party->index) continue;
// Verify modulus size
verified_modulus_size[j] = scalar_bitlength(reda->payload[j]->paillier_pub->N) >= 8*PAILLIER_MODULUS_BYTES-1;
// Verify shared public X_j^k is valid from party j
group_operation(combined_public, NULL, NULL, NULL, party->ec);
for (uint64_t k = 0; k < party->num_parties; ++k) {
group_operation(combined_public, combined_public, reda->payload[j]->reshare_public_X_k[k], NULL, party->ec);
}
verified_public_shares[j] = group_elem_is_ident(combined_public, party->ec) == 1;
// Verify commited V_i
cmp_refresh_round_1_commit(ver_data, party->sid, party->parties_ids[j], party->num_parties, party->ec, reda->payload[j]);
verified_decomm[j] = memcmp(ver_data, reda->payload[j]->V, sizeof(hash_chunk)) == 0;
// Verify echo broadcast of round 1 commitment -- ToDo: expand to identification of malicious party
verified_echo[j] = memcmp(reda->echo_broadcast, reda->payload[j]->echo_broadcast, sizeof(hash_chunk)) == 0;
if (verified_modulus_size[j] != 1) printf("%sParty %lu: N_i bitlength from Party %lu\n",ERR_STR, party->index, j);