2 This file is part of GNUnet.
3 (C) 2013 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file secretsharing/gnunet-service-secretsharing.c
23 * @brief secret sharing service
24 * @author Florian Dold
27 #include "gnunet_util_lib.h"
28 #include "gnunet_time_lib.h"
29 #include "gnunet_signatures.h"
30 #include "gnunet_consensus_service.h"
31 #include "secretsharing.h"
32 #include "secretsharing_protocol.h"
36 #define EXTRA_CHECKS 1
40 * Info about a peer in a key generation session.
45 * Peer identity of the peer.
47 struct GNUNET_PeerIdentity peer;
50 * The peer's paillier public key.
51 * Freshly generated for each keygen session.
53 struct GNUNET_CRYPTO_PaillierPublicKey paillier_public_key;
56 * The peer's commitment to his presecret.
58 gcry_mpi_t presecret_commitment;
61 * Commitment to the preshare that is
62 * intended for our peer.
64 gcry_mpi_t preshare_commitment;
67 * Sigma (exponentiated share) for this peer.
72 * Did we successfully receive the round1 element
78 * Did we successfully receive the round2 element
86 * Information about a peer in a decrypt session.
88 struct DecryptPeerInfo
91 * Identity of the peer.
93 struct GNUNET_PeerIdentity peer;
96 * Original index in the key generation round.
97 * Necessary for computing the lagrange coefficients.
99 unsigned int original_index;
102 * Set to the partial decryption of
103 * this peer, or NULL if we did not
104 * receive a partial decryption from this
105 * peer or the zero knowledge proof failed.
107 gcry_mpi_t partial_decryption;
112 * Session to establish a threshold-shared secret.
117 * Keygen sessions are held in a linked list.
119 struct KeygenSession *next;
122 * Keygen sessions are held in a linked list.
124 struct KeygenSession *prev;
127 * Current consensus, used for both DKG rounds.
129 struct GNUNET_CONSENSUS_Handle *consensus;
132 * Client that is interested in the result
133 * of this key generation session.
135 struct GNUNET_SERVER_Client *client;
138 * Message queue for 'client'
140 struct GNUNET_MQ_Handle *client_mq;
143 * Randomly generated coefficients of the polynomial for sharing our
144 * pre-secret, where 'preshares[0]' is our pre-secret. Contains 'threshold'
145 * elements, thus represents a polynomial of degree 'threshold-1', which can
146 * be interpolated with 'threshold' data points.
148 * The pre-secret-shares 'i=1,...,num_peers' are given by evaluating this
149 * polyomial at 'i' for share i.
151 gcry_mpi_t *presecret_polynomial;
154 * Minimum number of shares required to restore the secret.
155 * Also the number of coefficients for the polynomial representing
156 * the sharing. Obviously, the polynomial then has degree threshold-1.
158 unsigned int threshold;
161 * Total number of peers.
163 unsigned int num_peers;
166 * Index of the local peer.
168 unsigned int local_peer;
171 * Information about all participating peers.
172 * Array of size 'num_peers'.
174 struct KeygenPeerInfo *info;
177 * List of all peers involved in the secret sharing session.
179 struct GNUNET_PeerIdentity *peers;
182 * Identifier for this session.
184 struct GNUNET_HashCode session_id;
187 * Paillier private key of our peer.
189 struct GNUNET_CRYPTO_PaillierPrivateKey paillier_private_key;
192 * When would we like the key to be established?
194 struct GNUNET_TIME_Absolute deadline;
197 * When does the DKG start? Necessary to compute fractions of the
198 * operation's desired time interval.
200 struct GNUNET_TIME_Absolute start_time;
203 * Index of the local peer in the ordered list
204 * of peers in the session.
206 unsigned int local_peer_idx;
209 * Share of our peer. Once preshares from other peers are received, they
210 * will be added to 'my'share.
215 * Public key, will be updated when a round2 element arrives.
217 gcry_mpi_t public_key;
222 * Session to cooperatively decrypt a value.
224 struct DecryptSession
227 * Decrypt sessions are stored in a linked list.
229 struct DecryptSession *next;
232 * Decrypt sessions are stored in a linked list.
234 struct DecryptSession *prev;
237 * Handle to the consensus over partial decryptions.
239 struct GNUNET_CONSENSUS_Handle *consensus;
242 * Client connected to us.
244 struct GNUNET_SERVER_Client *client;
247 * Message queue for 'client'.
249 struct GNUNET_MQ_Handle *client_mq;
252 * When should we start communicating for decryption?
254 struct GNUNET_TIME_Absolute start;
257 * When would we like the ciphertext to be
260 struct GNUNET_TIME_Absolute deadline;
263 * Ciphertext we want to decrypt.
265 struct GNUNET_SECRETSHARING_Ciphertext ciphertext;
268 * Share of the local peer.
269 * Containts other important information, such as
270 * the list of other peers.
272 struct GNUNET_SECRETSHARING_Share *share;
275 * State information about other peers.
277 struct DecryptPeerInfo *info;
282 * Decrypt sessions are held in a linked list.
284 static struct DecryptSession *decrypt_sessions_head;
287 * Decrypt sessions are held in a linked list.
289 static struct DecryptSession *decrypt_sessions_tail;
292 * Decrypt sessions are held in a linked list.
294 static struct KeygenSession *keygen_sessions_head;
297 * Decrypt sessions are held in a linked list.
299 static struct KeygenSession *keygen_sessions_tail;
302 * The ElGamal prime field order as libgcrypt mpi.
303 * Initialized in #init_crypto_constants.
305 static gcry_mpi_t elgamal_q;
308 * Modulus of the prime field used for ElGamal.
309 * Initialized in #init_crypto_constants.
311 static gcry_mpi_t elgamal_p;
314 * Generator for prime field of order 'elgamal_q'.
315 * Initialized in #init_crypto_constants.
317 static gcry_mpi_t elgamal_g;
320 * Peer that runs this service.
322 static struct GNUNET_PeerIdentity my_peer;
325 * Peer that runs this service.
327 static struct GNUNET_CRYPTO_EddsaPrivateKey *my_peer_private_key;
330 * Configuration of this service.
332 static const struct GNUNET_CONFIGURATION_Handle *cfg;
335 * Server for this service.
337 static struct GNUNET_SERVER_Handle *srv;
341 * Get the peer info belonging to a peer identity in a keygen session.
343 * @param ks The keygen session.
344 * @param peer The peer identity.
345 * @return The Keygen peer info, or NULL if the peer could not be found.
347 static struct KeygenPeerInfo *
348 get_keygen_peer_info (const struct KeygenSession *ks,
349 const struct GNUNET_PeerIdentity *peer)
352 for (i = 0; i < ks->num_peers; i++)
353 if (0 == memcmp (peer, &ks->info[i].peer, sizeof (struct GNUNET_PeerIdentity)))
360 * Get the peer info belonging to a peer identity in a decrypt session.
362 * @param ds The decrypt session.
363 * @param peer The peer identity.
364 * @return The decrypt peer info, or NULL if the peer could not be found.
366 static struct DecryptPeerInfo *
367 get_decrypt_peer_info (const struct DecryptSession *ds,
368 const struct GNUNET_PeerIdentity *peer)
371 for (i = 0; i < ds->share->num_peers; i++)
372 if (0 == memcmp (peer, &ds->info[i].peer, sizeof (struct GNUNET_PeerIdentity)))
379 * Interpolate between two points in time.
381 * @param start start time
382 * @param end end time
383 * @param num numerator of the scale factor
384 * @param denum denumerator of the scale factor
386 static struct GNUNET_TIME_Absolute
387 time_between (struct GNUNET_TIME_Absolute start,
388 struct GNUNET_TIME_Absolute end,
391 struct GNUNET_TIME_Absolute result;
394 GNUNET_assert (start.abs_value_us <= end.abs_value_us);
395 diff = end.abs_value_us - start.abs_value_us;
396 result.abs_value_us = start.abs_value_us + ((diff * num) / denum);
403 * Compare two peer identities. Indended to be used with qsort or bsearch.
405 * @param p1 Some peer identity.
406 * @param p2 Some peer identity.
407 * @return 1 if p1 > p2, -1 if p1 < p2 and 0 if p1 == p2.
410 peer_id_cmp (const void *p1, const void *p2)
412 return memcmp (p1, p2, sizeof (struct GNUNET_PeerIdentity));
417 * Get the index of a peer in an array of peers
419 * @param haystack Array of peers.
420 * @param n Size of @a haystack.
421 * @param needle Peer to find
422 * @return Index of @a needle in @a haystack, or -1 if peer
423 * is not in the list.
426 peer_find (const struct GNUNET_PeerIdentity *haystack, unsigned int n,
427 const struct GNUNET_PeerIdentity *needle)
430 for (i = 0; i < n; i++)
431 if (0 == memcmp (&haystack[i], needle, sizeof (struct GNUNET_PeerIdentity)))
438 * Normalize the given list of peers, by including the local peer
439 * (if it is missing) and sorting the peers by their identity.
441 * @param listed Peers in the unnormalized list.
442 * @param num_listed Peers in the un-normalized list.
443 * @param[out] num_normalized Number of peers in the normalized list.
444 * @param[out] my_peer_idx Index of the local peer in the normalized list.
445 * @return Normalized list, must be free'd by the caller.
447 static struct GNUNET_PeerIdentity *
448 normalize_peers (struct GNUNET_PeerIdentity *listed,
449 unsigned int num_listed,
450 unsigned int *num_normalized,
451 unsigned int *my_peer_idx)
453 unsigned int local_peer_in_list;
454 /* number of peers in the normalized list */
456 struct GNUNET_PeerIdentity *normalized;
458 local_peer_in_list = GNUNET_YES;
460 if (peer_find (listed, num_listed, &my_peer) < 0)
462 local_peer_in_list = GNUNET_NO;
466 normalized = GNUNET_new_array (n, struct GNUNET_PeerIdentity);
468 if (GNUNET_NO == local_peer_in_list)
469 normalized[n - 1] = my_peer;
471 memcpy (normalized, listed, num_listed * sizeof (struct GNUNET_PeerIdentity));
472 qsort (normalized, n, sizeof (struct GNUNET_PeerIdentity), &peer_id_cmp);
474 if (NULL != my_peer_idx)
475 *my_peer_idx = peer_find (normalized, n, &my_peer);
476 if (NULL != num_normalized)
484 * Get a the j-th lagrange coefficient for a set of indices.
486 * @param[out] coeff the lagrange coefficient
487 * @param j lagrange coefficient we want to compute
488 * @param indices indices
489 * @param num number of indices in @a indices
492 compute_lagrange_coefficient (gcry_mpi_t coeff, unsigned int j,
493 unsigned int *indices,
501 /* temp value for l-j */
504 GNUNET_assert (0 != coeff);
506 GNUNET_assert (0 != (n = gcry_mpi_new (0)));
507 GNUNET_assert (0 != (d = gcry_mpi_new (0)));
508 GNUNET_assert (0 != (tmp = gcry_mpi_new (0)));
510 gcry_mpi_set_ui (n, 1);
511 gcry_mpi_set_ui (d, 1);
513 for (i = 0; i < num; i++)
515 unsigned int l = indices[i];
518 gcry_mpi_mul_ui (n, n, l + 1);
520 gcry_mpi_set_ui (tmp, l + 1);
521 gcry_mpi_sub_ui (tmp, tmp, j + 1);
522 gcry_mpi_mul (d, d, tmp);
525 // gcry_mpi_invm does not like negative numbers ...
526 gcry_mpi_mod (d, d, elgamal_q);
528 GNUNET_assert (gcry_mpi_cmp_ui (d, 0) > 0);
530 // now we do the actual division, with everything mod q, as we
531 // are not operating on elements from <g>, but on exponents
532 GNUNET_assert (0 != gcry_mpi_invm (d, d, elgamal_q));
534 gcry_mpi_mulm (coeff, n, d, elgamal_q);
536 gcry_mpi_release (n);
537 gcry_mpi_release (d);
538 gcry_mpi_release (tmp);
543 * Destroy a decrypt session, removing it from
544 * the linked list of decrypt sessions.
546 * @param ds decrypt session to destroy
549 decrypt_session_destroy (struct DecryptSession *ds)
551 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying decrypt session\n");
553 GNUNET_CONTAINER_DLL_remove (decrypt_sessions_head, decrypt_sessions_tail, ds);
555 if (NULL != ds->consensus)
557 GNUNET_CONSENSUS_destroy (ds->consensus);
558 ds->consensus = NULL;
561 if (NULL != ds->info)
564 for (i = 0; i < ds->share->num_peers; i++)
566 if (NULL != ds->info[i].partial_decryption)
568 gcry_mpi_release (ds->info[i].partial_decryption);
569 ds->info[i].partial_decryption = NULL;
572 GNUNET_free (ds->info);
576 if (NULL != ds->share)
578 GNUNET_SECRETSHARING_share_destroy (ds->share);
582 if (NULL != ds->client_mq)
584 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying decrypt MQ\n");
585 GNUNET_MQ_destroy (ds->client_mq);
586 ds->client_mq = NULL;
589 if (NULL != ds->client)
591 GNUNET_SERVER_client_disconnect (ds->client);
599 keygen_info_destroy (struct KeygenPeerInfo *info)
601 if (NULL != info->sigma)
603 gcry_mpi_release (info->sigma);
606 if (NULL != info->presecret_commitment)
608 gcry_mpi_release (info->presecret_commitment);
609 info->presecret_commitment = NULL;
611 if (NULL != info->preshare_commitment)
613 gcry_mpi_release (info->preshare_commitment);
614 info->presecret_commitment = NULL;
620 keygen_session_destroy (struct KeygenSession *ks)
622 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying keygen session\n");
624 GNUNET_CONTAINER_DLL_remove (keygen_sessions_head, keygen_sessions_tail, ks);
626 if (NULL != ks->info)
629 for (i = 0; i < ks->num_peers; i++)
630 keygen_info_destroy (&ks->info[i]);
631 GNUNET_free (ks->info);
635 if (NULL != ks->consensus)
637 GNUNET_CONSENSUS_destroy (ks->consensus);
638 ks->consensus = NULL;
641 if (NULL != ks->presecret_polynomial)
644 for (i = 0; i < ks->threshold; i++)
646 GNUNET_assert (NULL != ks->presecret_polynomial[i]);
647 gcry_mpi_release (ks->presecret_polynomial[i]);
648 ks->presecret_polynomial[i] = NULL;
650 GNUNET_free (ks->presecret_polynomial);
651 ks->presecret_polynomial = NULL;
654 if (NULL != ks->client_mq)
656 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying keygen MQ\n");
657 GNUNET_MQ_destroy (ks->client_mq);
658 ks->client_mq = NULL;
661 if (NULL != ks->my_share)
663 gcry_mpi_release (ks->my_share);
667 if (NULL != ks->public_key)
669 gcry_mpi_release (ks->public_key);
670 ks->public_key = NULL;
673 if (NULL != ks->peers)
675 GNUNET_free (ks->peers);
679 if (NULL != ks->client)
681 GNUNET_SERVER_client_disconnect (ks->client);
690 * Task run during shutdown.
696 cleanup_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
698 while (NULL != decrypt_sessions_head)
699 decrypt_session_destroy (decrypt_sessions_head);
701 while (NULL != keygen_sessions_head)
702 keygen_session_destroy (keygen_sessions_head);
708 * Generate the random coefficients of our pre-secret polynomial
710 * @param ks the session
713 generate_presecret_polynomial (struct KeygenSession *ks)
718 GNUNET_assert (NULL == ks->presecret_polynomial);
719 ks->presecret_polynomial = GNUNET_new_array (ks->threshold, gcry_mpi_t);
720 for (i = 0; i < ks->threshold; i++)
722 v = ks->presecret_polynomial[i] = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS);
723 GNUNET_assert (NULL != v);
724 // Randomize v such that 0 < v < elgamal_q.
725 // The '- 1' is necessary as bitlength(q) = bitlength(p) - 1.
728 gcry_mpi_randomize (v, GNUNET_SECRETSHARING_ELGAMAL_BITS - 1, GCRY_WEAK_RANDOM);
729 } while ((gcry_mpi_cmp_ui (v, 0) == 0) || (gcry_mpi_cmp (v, elgamal_q) >= 0));
735 * Consensus element handler for round one.
736 * We should get one ephemeral key for each peer.
738 * @param cls Closure (keygen session).
739 * @param element The element from consensus, or
740 * NULL if consensus failed.
743 keygen_round1_new_element (void *cls,
744 const struct GNUNET_SET_Element *element)
746 const struct GNUNET_SECRETSHARING_KeygenCommitData *d;
747 struct KeygenSession *ks = cls;
748 struct KeygenPeerInfo *info;
752 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "round1 consensus failed\n");
756 /* elements have fixed size */
757 if (element->size != sizeof (struct GNUNET_SECRETSHARING_KeygenCommitData))
759 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
760 "keygen commit data with wrong size (%u) in consensus, "
762 element->size, sizeof (struct GNUNET_SECRETSHARING_KeygenCommitData));
766 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "got round1 element\n");
769 info = get_keygen_peer_info (ks, &d->peer);
773 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen commit data with wrong peer identity (%s) in consensus\n",
774 GNUNET_i2s (&d->peer));
778 /* Check that the right amount of data has been signed. */
779 if (d->purpose.size !=
780 htonl (element->size - offsetof (struct GNUNET_SECRETSHARING_KeygenCommitData, purpose)))
782 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen commit data with wrong signature purpose size in consensus\n");
786 if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG1,
787 &d->purpose, &d->signature, &d->peer.public_key))
789 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen commit data with invalid signature in consensus\n");
792 info->paillier_public_key = d->pubkey;
793 GNUNET_CRYPTO_mpi_scan_unsigned (&info->presecret_commitment, &d->commitment, 512 / 8);
794 info->round1_valid = GNUNET_YES;
799 * Evaluate the polynomial with coefficients @a coeff at @a x.
800 * The i-th element in @a coeff corresponds to the coefficient of x^i.
802 * @param[out] z result of the evaluation
803 * @param coeff array of coefficients
804 * @param num_coeff number of coefficients
805 * @param x where to evaluate the polynomial
806 * @param m what group are we operating in?
809 horner_eval (gcry_mpi_t z, gcry_mpi_t *coeff, unsigned int num_coeff, gcry_mpi_t x, gcry_mpi_t m)
813 gcry_mpi_set_ui (z, 0);
814 for (i = 0; i < num_coeff; i++)
817 gcry_mpi_mul (z, z, x);
818 gcry_mpi_addm (z, z, coeff[num_coeff - i - 1], m);
824 keygen_round2_conclude (void *cls)
826 struct KeygenSession *ks = cls;
827 struct GNUNET_SECRETSHARING_SecretReadyMessage *m;
828 struct GNUNET_MQ_Envelope *ev;
832 struct GNUNET_SECRETSHARING_Share *share;
834 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "round2 conclude\n");
836 GNUNET_CONSENSUS_destroy (ks->consensus);
837 ks->consensus = NULL;
839 share = GNUNET_new (struct GNUNET_SECRETSHARING_Share);
841 share->num_peers = 0;
843 for (i = 0; i < ks->num_peers; i++)
844 if (GNUNET_YES == ks->info[i].round2_valid)
847 share->peers = GNUNET_new_array (share->num_peers, struct GNUNET_PeerIdentity);
849 GNUNET_new_array (share->num_peers, struct GNUNET_SECRETSHARING_FieldElement);
850 share->original_indices = GNUNET_new_array (share->num_peers, uint16_t);
852 /* maybe we're not even in the list of peers? */
853 share->my_peer = share->num_peers;
855 j = 0; /* running index of valid peers */
856 for (i = 0; i < ks->num_peers; i++)
858 if (GNUNET_YES == ks->info[i].round2_valid)
860 share->peers[j] = ks->info[i].peer;
861 GNUNET_CRYPTO_mpi_print_unsigned (&share->sigmas[j],
862 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
864 share->original_indices[i] = j;
865 if (0 == memcmp (&share->peers[i], &my_peer, sizeof (struct GNUNET_PeerIdentity)))
871 if (share->my_peer == share->num_peers)
873 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "P%u: peer identity not in share\n", ks->local_peer_idx);
876 GNUNET_CRYPTO_mpi_print_unsigned (&share->my_share, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
878 GNUNET_CRYPTO_mpi_print_unsigned (&share->public_key, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
881 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "keygen completed with %u peers\n", share->num_peers);
883 /* Write the share. If 0 peers completed the dkg, an empty
884 * share will be sent. */
886 GNUNET_assert (GNUNET_OK == GNUNET_SECRETSHARING_share_write (share, NULL, 0, &share_size));
888 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "writing share of size %u\n",
889 (unsigned int) share_size);
891 ev = GNUNET_MQ_msg_extra (m, share_size,
892 GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_SECRET_READY);
894 GNUNET_assert (GNUNET_OK == GNUNET_SECRETSHARING_share_write (share, &m[1], share_size, NULL));
896 GNUNET_SECRETSHARING_share_destroy (share);
899 GNUNET_MQ_send (ks->client_mq, ev);
905 restore_fair (const struct GNUNET_CRYPTO_PaillierPublicKey *ppub,
906 const struct GNUNET_SECRETSHARING_FairEncryption *fe,
907 gcry_mpi_t x, gcry_mpi_t xres)
924 GNUNET_assert (NULL != (n = gcry_mpi_new (0)));
925 GNUNET_assert (NULL != (t = gcry_mpi_new (0)));
926 GNUNET_assert (NULL != (t_1 = gcry_mpi_new (0)));
927 GNUNET_assert (NULL != (t_2 = gcry_mpi_new (0)));
928 GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
929 GNUNET_assert (NULL != (big_t = gcry_mpi_new (0)));
930 GNUNET_assert (NULL != (v = gcry_mpi_new (0)));
931 GNUNET_assert (NULL != (big_a = gcry_mpi_new (0)));
932 GNUNET_assert (NULL != (big_b = gcry_mpi_new (0)));
935 GNUNET_CRYPTO_mpi_scan_unsigned (&a_1, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
936 GNUNET_assert (NULL != (a_2 = gcry_mpi_new (0)));
937 gcry_mpi_set_ui (a_2, 0);
939 GNUNET_assert (NULL != (b_1 = gcry_mpi_new (0)));
940 gcry_mpi_set (b_1, x);
941 GNUNET_assert (NULL != (b_2 = gcry_mpi_new (0)));
942 gcry_mpi_set_ui (b_2, 1);
945 gcry_mpi_mul (t, a_1, a_1);
946 gcry_mpi_mul (big_a, a_2, a_2);
947 gcry_mpi_add (big_a, big_a, t);
950 gcry_mpi_mul (t, b_1, b_1);
951 gcry_mpi_mul (big_b, b_2, b_2);
952 gcry_mpi_add (big_b, big_b, t);
957 gcry_mpi_mul (t, a_1, b_1);
958 gcry_mpi_mul (n, a_2, b_2);
959 gcry_mpi_add (n, n, t);
962 gcry_mpi_div (r, NULL, n, big_b, 0);
964 // T := A - 2rn + rrB
965 gcry_mpi_mul (v, r, n);
966 gcry_mpi_mul_ui (v, v, 2);
967 gcry_mpi_sub (big_t, big_a, v);
968 gcry_mpi_mul (v, r, r);
969 gcry_mpi_mul (v, v, big_b);
970 gcry_mpi_add (big_t, big_t, v);
972 if (gcry_mpi_cmp (big_t, big_b) >= 0)
978 gcry_mpi_mul (v, r, b_1);
979 gcry_mpi_sub (t_1, a_1, v);
980 gcry_mpi_mul (v, r, b_2);
981 gcry_mpi_sub (t_2, a_2, v);
984 gcry_mpi_set (a_1, b_1);
985 gcry_mpi_set (a_2, b_2);
987 gcry_mpi_set (b_1, t_1);
988 gcry_mpi_set (b_2, t_2);
990 gcry_mpi_set (big_a, big_b);
991 gcry_mpi_set (big_b, big_t);
995 gcry_mpi_t paillier_n;
997 GNUNET_CRYPTO_mpi_scan_unsigned (&paillier_n, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
999 gcry_mpi_set (xres, b_2);
1000 gcry_mpi_invm (xres, xres, elgamal_q);
1001 gcry_mpi_mulm (xres, xres, b_1, elgamal_q);
1009 get_fair_encryption_challenge (const struct GNUNET_SECRETSHARING_FairEncryption *fe, gcry_mpi_t e)
1012 struct GNUNET_CRYPTO_PaillierCiphertext c;
1013 char h[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
1014 char t1[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
1015 char t2[GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8];
1017 struct GNUNET_HashCode e_hash;
1019 memcpy (&hash_data.c, &fe->c, sizeof (struct GNUNET_CRYPTO_PaillierCiphertext));
1020 memcpy (&hash_data.h, &fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1021 memcpy (&hash_data.t1, &fe->t1, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1022 memcpy (&hash_data.t2, &fe->t2, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
1024 GNUNET_CRYPTO_mpi_scan_unsigned (&e, &e_hash, sizeof (struct GNUNET_HashCode));
1025 gcry_mpi_mod (e, e, elgamal_q);
1030 verify_fair (const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, const struct GNUNET_SECRETSHARING_FairEncryption *fe)
1044 GNUNET_assert (NULL != (n_sq = gcry_mpi_new (0)));
1045 GNUNET_assert (NULL != (tmp1 = gcry_mpi_new (0)));
1046 GNUNET_assert (NULL != (tmp2 = gcry_mpi_new (0)));
1047 GNUNET_assert (NULL != (e = gcry_mpi_new (0)));
1049 get_fair_encryption_challenge (fe, e);
1051 GNUNET_CRYPTO_mpi_scan_unsigned (&n, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
1052 GNUNET_CRYPTO_mpi_scan_unsigned (&t1, fe->t1, GNUNET_CRYPTO_PAILLIER_BITS / 8);
1053 GNUNET_CRYPTO_mpi_scan_unsigned (&z, fe->z, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1054 GNUNET_CRYPTO_mpi_scan_unsigned (&y, fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1055 GNUNET_CRYPTO_mpi_scan_unsigned (&w, fe->w, GNUNET_CRYPTO_PAILLIER_BITS / 8);
1056 GNUNET_CRYPTO_mpi_scan_unsigned (&big_y, fe->c.bits, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
1057 GNUNET_CRYPTO_mpi_scan_unsigned (&t2, fe->t2, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
1058 gcry_mpi_mul (n_sq, n, n);
1061 gcry_mpi_powm (tmp1, elgamal_g, z, elgamal_p);
1063 gcry_mpi_powm (tmp1, y, e, elgamal_p);
1064 gcry_mpi_invm (tmp1, tmp1, elgamal_p);
1065 // tmp1 = tmp1 * tmp2
1066 gcry_mpi_mulm (tmp1, tmp1, tmp2, elgamal_p);
1068 if (0 == gcry_mpi_cmp (t1, tmp1))
1070 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "fair encryption invalid (t1)\n");
1074 gcry_mpi_powm (big_y, big_y, e, n_sq);
1075 gcry_mpi_invm (big_y, big_y, n_sq);
1077 gcry_mpi_add_ui (tmp1, n, 1);
1078 gcry_mpi_powm (tmp1, tmp1, z, n_sq);
1080 gcry_mpi_powm (tmp2, w, n, n_sq);
1082 gcry_mpi_mulm (tmp1, tmp1, tmp2, n_sq);
1083 gcry_mpi_mulm (tmp1, tmp1, big_y, n_sq);
1086 if (0 == gcry_mpi_cmp (t2, tmp1))
1088 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "fair encryption invalid (t2)\n");
1097 * Create a fair Paillier encryption of then given ciphertext.
1099 * @param v the ciphertext
1100 * @param[out] fe the fair encryption
1103 encrypt_fair (gcry_mpi_t v, const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, struct GNUNET_SECRETSHARING_FairEncryption *fe)
1118 GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
1119 GNUNET_assert (NULL != (s = gcry_mpi_new (0)));
1120 GNUNET_assert (NULL != (t1 = gcry_mpi_new (0)));
1121 GNUNET_assert (NULL != (t2 = gcry_mpi_new (0)));
1122 GNUNET_assert (NULL != (z = gcry_mpi_new (0)));
1123 GNUNET_assert (NULL != (w = gcry_mpi_new (0)));
1124 GNUNET_assert (NULL != (n_sq = gcry_mpi_new (0)));
1125 GNUNET_assert (NULL != (e = gcry_mpi_new (0)));
1126 GNUNET_assert (NULL != (u = gcry_mpi_new (0)));
1127 GNUNET_assert (NULL != (Y = gcry_mpi_new (0)));
1128 GNUNET_assert (NULL != (G = gcry_mpi_new (0)));
1129 GNUNET_assert (NULL != (h = gcry_mpi_new (0)));
1131 GNUNET_CRYPTO_mpi_scan_unsigned (&n, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
1132 gcry_mpi_mul (n_sq, n, n);
1133 gcry_mpi_add_ui (G, n, 1);
1136 gcry_mpi_randomize (u, GNUNET_CRYPTO_PAILLIER_BITS, GCRY_WEAK_RANDOM);
1138 while (gcry_mpi_cmp (u, n) >= 0);
1140 gcry_mpi_powm (t1, G, v, n_sq);
1141 gcry_mpi_powm (t2, u, n, n_sq);
1142 gcry_mpi_mulm (Y, t1, t2, n_sq);
1144 GNUNET_CRYPTO_mpi_print_unsigned (fe->c.bits,
1149 gcry_mpi_randomize (r, 2048, GCRY_WEAK_RANDOM);
1151 gcry_mpi_randomize (s, GNUNET_CRYPTO_PAILLIER_BITS, GCRY_WEAK_RANDOM);
1153 while (gcry_mpi_cmp (s, n) >= 0);
1156 gcry_mpi_mulm (t1, elgamal_g, r, elgamal_p);
1157 // compute t2 (use z and w as temp)
1158 gcry_mpi_powm (z, G, r, n_sq);
1159 gcry_mpi_powm (w, s, n, n_sq);
1160 gcry_mpi_mulm (t2, z, w, n_sq);
1163 gcry_mpi_powm (h, elgamal_g, v, elgamal_p);
1165 GNUNET_CRYPTO_mpi_print_unsigned (fe->h,
1166 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
1169 GNUNET_CRYPTO_mpi_print_unsigned (fe->t1,
1170 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
1173 GNUNET_CRYPTO_mpi_print_unsigned (fe->t2,
1174 GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8,
1178 get_fair_encryption_challenge (fe, e);
1181 gcry_mpi_mul (z, e, v);
1182 gcry_mpi_addm (z, z, r, elgamal_q);
1184 gcry_mpi_powm (w, u, e, n);
1185 gcry_mpi_mulm (w, w, s, n);
1187 GNUNET_CRYPTO_mpi_print_unsigned (fe->z,
1188 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
1191 GNUNET_CRYPTO_mpi_print_unsigned (fe->w,
1192 GNUNET_CRYPTO_PAILLIER_BITS / 8,
1195 gcry_mpi_release (n);
1196 gcry_mpi_release (r);
1197 gcry_mpi_release (s);
1198 gcry_mpi_release (t1);
1199 gcry_mpi_release (t2);
1200 gcry_mpi_release (z);
1201 gcry_mpi_release (w);
1202 gcry_mpi_release (e);
1203 gcry_mpi_release (n_sq);
1204 gcry_mpi_release (u);
1205 gcry_mpi_release (Y);
1206 gcry_mpi_release (G);
1207 gcry_mpi_release (h);
1212 * Insert round 2 element in the consensus, consisting of
1213 * (1) The exponentiated pre-share polynomial coefficients A_{i,l}=g^{a_{i,l}}
1214 * (2) The exponentiated pre-shares y_{i,j}=g^{s_{i,j}}
1215 * (3) The encrypted pre-shares Y_{i,j}
1216 * (4) The zero knowledge proof for fairness of
1219 * @param ks session to use
1222 insert_round2_element (struct KeygenSession *ks)
1224 struct GNUNET_SET_Element *element;
1225 struct GNUNET_SECRETSHARING_KeygenRevealData *d;
1227 unsigned char *last_pos;
1228 size_t element_size;
1233 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting round2 element\n",
1234 ks->local_peer_idx);
1236 GNUNET_assert (NULL != (v = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
1237 GNUNET_assert (NULL != (idx = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
1239 element_size = (sizeof (struct GNUNET_SECRETSHARING_KeygenRevealData) +
1240 sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers +
1241 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->threshold);
1243 element = GNUNET_malloc (sizeof (struct GNUNET_SET_Element) + element_size);
1244 element->size = element_size;
1245 element->data = (void *) &element[1];
1247 d = (void *) element->data;
1250 // start inserting vector elements
1251 // after the fixed part of the element's data
1252 pos = (void *) &d[1];
1253 last_pos = pos + element_size;
1255 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed exp preshares\n",
1256 ks->local_peer_idx);
1258 // encrypted pre-shares
1259 // and fair encryption proof
1261 for (i = 0; i < ks->num_peers; i++)
1263 ptrdiff_t remaining = last_pos - pos;
1264 struct GNUNET_SECRETSHARING_FairEncryption *fe = (void *) pos;
1266 GNUNET_assert (remaining > 0);
1267 memset (fe, 0, sizeof *fe);
1268 if (GNUNET_YES == ks->info[i].round1_valid)
1270 gcry_mpi_set_ui (idx, i + 1);
1271 // evaluate the polynomial
1272 horner_eval (v, ks->presecret_polynomial, ks->threshold, idx, elgamal_q);
1273 // encrypt the result
1274 encrypt_fair (v, &ks->info[i].paillier_public_key, fe);
1280 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed enc preshares\n",
1281 ks->local_peer_idx);
1283 // exponentiated coefficients
1284 for (i = 0; i < ks->threshold; i++)
1286 ptrdiff_t remaining = last_pos - pos;
1287 GNUNET_assert (remaining > 0);
1288 gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[i], elgamal_p);
1289 GNUNET_CRYPTO_mpi_print_unsigned (pos, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, v);
1290 pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8;
1293 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed exp coefficients\n",
1294 ks->local_peer_idx);
1297 d->purpose.size = htonl (element_size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData, purpose));
1298 d->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG2);
1299 GNUNET_CRYPTO_eddsa_sign (my_peer_private_key, &d->purpose, &d->signature);
1301 GNUNET_CONSENSUS_insert (ks->consensus, element, NULL, NULL);
1302 GNUNET_free (element); /* FIXME: maybe stack-allocate instead? */
1304 gcry_mpi_release (v);
1305 gcry_mpi_release (idx);
1310 keygen_reveal_get_exp_coeff (struct KeygenSession *ks,
1311 const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
1315 gcry_mpi_t exp_coeff;
1317 GNUNET_assert (idx < ks->threshold);
1319 pos = (void *) &d[1];
1320 // skip encrypted pre-shares
1321 pos += sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers;
1322 // skip exp. coeffs we are not interested in
1323 pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * idx;
1324 // the first exponentiated coefficient is the public key share
1325 GNUNET_CRYPTO_mpi_scan_unsigned (&exp_coeff, pos, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1330 static struct GNUNET_SECRETSHARING_FairEncryption *
1331 keygen_reveal_get_enc_preshare (struct KeygenSession *ks,
1332 const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
1337 GNUNET_assert (idx < ks->num_peers);
1339 pos = (void *) &d[1];
1340 // skip encrypted pre-shares we're not interested in
1341 pos += sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * idx;
1342 return (struct GNUNET_SECRETSHARING_FairEncryption *) pos;
1347 keygen_reveal_get_exp_preshare (struct KeygenSession *ks,
1348 const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
1352 gcry_mpi_t exp_preshare;
1353 struct GNUNET_SECRETSHARING_FairEncryption *fe;
1355 GNUNET_assert (idx < ks->num_peers);
1357 fe = keygen_reveal_get_enc_preshare (ks, d, idx);
1358 pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * idx;
1359 GNUNET_CRYPTO_mpi_scan_unsigned (&exp_preshare, fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1360 return exp_preshare;
1366 keygen_round2_new_element (void *cls,
1367 const struct GNUNET_SET_Element *element)
1369 struct KeygenSession *ks = cls;
1370 const struct GNUNET_SECRETSHARING_KeygenRevealData *d;
1371 struct KeygenPeerInfo *info;
1372 size_t expected_element_size;
1376 gcry_mpi_t public_key_share;
1377 gcry_mpi_t preshare;
1379 if (NULL == element)
1381 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "round2 consensus failed\n");
1385 expected_element_size = (sizeof (struct GNUNET_SECRETSHARING_KeygenRevealData) +
1386 sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers +
1387 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->threshold);
1389 if (element->size != expected_element_size)
1391 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1392 "keygen round2 data with wrong size (%u) in consensus, "
1394 element->size, expected_element_size);
1398 d = (const void *) element->data;
1400 info = get_keygen_peer_info (ks, &d->peer);
1404 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen commit data with wrong peer identity (%s) in consensus\n",
1405 GNUNET_i2s (&d->peer));
1409 if (GNUNET_NO == info->round1_valid)
1411 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1412 "ignoring round2 element from peer with invalid round1 element (%s)\n",
1413 GNUNET_i2s (&d->peer));
1417 if (GNUNET_YES == info->round2_valid)
1419 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1420 "ignoring duplicate round2 element (%s)\n",
1421 GNUNET_i2s (&d->peer));
1425 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "got round2 element\n");
1427 if (ntohl (d->purpose.size) !=
1428 element->size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData, purpose))
1430 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen reveal data with wrong signature purpose size in consensus\n");
1434 if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG2,
1435 &d->purpose, &d->signature, &d->peer.public_key))
1437 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen reveal data with invalid signature in consensus\n");
1441 public_key_share = keygen_reveal_get_exp_coeff (ks, d, 0);
1442 info->preshare_commitment = keygen_reveal_get_exp_preshare (ks, d, ks->local_peer_idx);
1444 if (NULL == ks->public_key)
1446 GNUNET_assert (NULL != (ks->public_key = gcry_mpi_new (0)));
1447 gcry_mpi_set_ui (ks->public_key, 1);
1449 gcry_mpi_mulm (ks->public_key, ks->public_key, public_key_share, elgamal_p);
1451 gcry_mpi_release (public_key_share);
1452 public_key_share = NULL;
1455 struct GNUNET_SECRETSHARING_FairEncryption *fe = keygen_reveal_get_enc_preshare (ks, d, ks->local_peer_idx);
1457 GNUNET_assert (NULL != (preshare = gcry_mpi_new (0)));
1458 GNUNET_CRYPTO_paillier_decrypt (&ks->paillier_private_key,
1459 &ks->info[ks->local_peer_idx].paillier_public_key,
1463 GNUNET_assert (NULL != (resx = gcry_mpi_new (0)));
1465 // FIXME: not doing the restoration is less expensive
1467 restore_fair (&ks->info[ks->local_peer_idx].paillier_public_key, fe, preshare, preshare);
1469 //if (gcry_mpi_cmp (resx, preshare) != 0)
1471 // GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "fair encryption restore failed\n");
1476 GNUNET_assert (NULL != (tmp = gcry_mpi_new (0)));
1477 gcry_mpi_powm (tmp, elgamal_g, preshare, elgamal_p);
1479 cmp_result = gcry_mpi_cmp (tmp, info->preshare_commitment);
1480 gcry_mpi_release (tmp);
1482 if (0 != cmp_result)
1484 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: Got invalid presecret from P%u\n",
1485 (unsigned int) ks->local_peer_idx, (unsigned int) (info - ks->info));
1489 if (NULL == ks->my_share)
1491 GNUNET_assert (NULL != (ks->my_share = gcry_mpi_new (0)));
1493 gcry_mpi_addm (ks->my_share, ks->my_share, preshare, elgamal_q);
1495 for (j = 0; j < ks->num_peers; j++)
1497 gcry_mpi_t presigma;
1498 if (NULL == ks->info[j].sigma)
1500 GNUNET_assert (NULL != (ks->info[j].sigma = gcry_mpi_new (0)));
1501 gcry_mpi_set_ui (ks->info[j].sigma, 1);
1503 presigma = keygen_reveal_get_exp_preshare (ks, d, j);
1504 gcry_mpi_mulm (ks->info[j].sigma, ks->info[j].sigma, presigma, elgamal_p);
1505 gcry_mpi_release (presigma);
1509 GNUNET_assert (NULL != (prod = gcry_mpi_new (0)));
1511 GNUNET_assert (NULL != (j_to_k = gcry_mpi_new (0)));
1512 // validate that the polynomial sharing matches the additive sharing
1513 for (j = 0; j < ks->num_peers; j++)
1517 gcry_mpi_t exp_preshare;
1518 gcry_mpi_set_ui (prod, 1);
1519 for (k = 0; k < ks->threshold; k++)
1521 // Using pow(double,double) is a bit sketchy.
1522 // We count players from 1, but shares from 0.
1524 gcry_mpi_set_ui (j_to_k, (unsigned int) pow(j+1, k));
1525 tmp = keygen_reveal_get_exp_coeff (ks, d, k);
1526 gcry_mpi_powm (tmp, tmp, j_to_k, elgamal_p);
1527 gcry_mpi_mulm (prod, prod, tmp, elgamal_p);
1528 gcry_mpi_release (tmp);
1530 exp_preshare = keygen_reveal_get_exp_preshare (ks, d, j);
1531 gcry_mpi_mod (exp_preshare, exp_preshare, elgamal_p);
1532 cmp_result = gcry_mpi_cmp (prod, exp_preshare);
1533 gcry_mpi_release (exp_preshare);
1534 exp_preshare = NULL;
1535 if (0 != cmp_result)
1537 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: reveal data from P%u incorrect\n",
1538 ks->local_peer_idx, j);
1539 /* no need for further verification, round2 stays invalid ... */
1544 // TODO: verify proof of fair encryption (once implemented)
1545 for (j = 0; j < ks->num_peers; j++)
1547 struct GNUNET_SECRETSHARING_FairEncryption *fe = keygen_reveal_get_enc_preshare (ks, d, j);
1548 if (GNUNET_YES != verify_fair (&ks->info[j].paillier_public_key, fe))
1550 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: reveal data from P%u incorrect (fair encryption)\n",
1551 ks->local_peer_idx, j);
1557 info->round2_valid = GNUNET_YES;
1559 gcry_mpi_release (preshare);
1560 gcry_mpi_release (prod);
1561 gcry_mpi_release (j_to_k);
1566 * Called when the first consensus round has concluded.
1567 * Will initiate the second round.
1569 * @param cls closure
1572 keygen_round1_conclude (void *cls)
1574 struct KeygenSession *ks = cls;
1576 GNUNET_CONSENSUS_destroy (ks->consensus);
1578 ks->consensus = GNUNET_CONSENSUS_create (cfg, ks->num_peers, ks->peers, &ks->session_id,
1579 time_between (ks->start_time, ks->deadline, 1, 2),
1581 keygen_round2_new_element, ks);
1583 insert_round2_element (ks);
1585 GNUNET_CONSENSUS_conclude (ks->consensus,
1586 keygen_round2_conclude,
1592 * Insert the ephemeral key and the presecret commitment
1593 * of this peer in the consensus of the given session.
1595 * @param ks session to use
1598 insert_round1_element (struct KeygenSession *ks)
1600 struct GNUNET_SET_Element *element;
1601 struct GNUNET_SECRETSHARING_KeygenCommitData *d;
1604 // big-endian representation of 'v'
1605 unsigned char v_data[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
1607 element = GNUNET_malloc (sizeof *element + sizeof *d);
1608 d = (void *) &element[1];
1610 element->size = sizeof *d;
1614 GNUNET_assert (0 != (v = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
1616 gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[0], elgamal_p);
1618 GNUNET_CRYPTO_mpi_print_unsigned (v_data, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, v);
1620 GNUNET_CRYPTO_hash (v_data, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, &d->commitment);
1622 d->pubkey = ks->info[ks->local_peer_idx].paillier_public_key;
1624 d->purpose.size = htonl ((sizeof *d) - offsetof (struct GNUNET_SECRETSHARING_KeygenCommitData, purpose));
1625 d->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG1);
1626 GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_eddsa_sign (my_peer_private_key, &d->purpose, &d->signature));
1628 GNUNET_CONSENSUS_insert (ks->consensus, element, NULL, NULL);
1630 gcry_mpi_release (v);
1631 GNUNET_free (element);
1636 * Functions with this signature are called whenever a message is
1639 * @param cls closure
1640 * @param client identification of the client
1641 * @param message the actual message
1643 static void handle_client_keygen (void *cls,
1644 struct GNUNET_SERVER_Client *client,
1645 const struct GNUNET_MessageHeader
1648 const struct GNUNET_SECRETSHARING_CreateMessage *msg =
1649 (const struct GNUNET_SECRETSHARING_CreateMessage *) message;
1650 struct KeygenSession *ks;
1653 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "client requested key generation\n");
1655 ks = GNUNET_new (struct KeygenSession);
1657 /* FIXME: check if client already has some session */
1659 GNUNET_CONTAINER_DLL_insert (keygen_sessions_head, keygen_sessions_tail, ks);
1661 ks->client = client;
1662 ks->client_mq = GNUNET_MQ_queue_for_server_client (client);
1664 ks->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
1665 ks->threshold = ntohs (msg->threshold);
1666 ks->num_peers = ntohs (msg->num_peers);
1668 ks->peers = normalize_peers ((struct GNUNET_PeerIdentity *) &msg[1], ks->num_peers,
1669 &ks->num_peers, &ks->local_peer_idx);
1672 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "first round of consensus with %u peers\n", ks->num_peers);
1673 ks->consensus = GNUNET_CONSENSUS_create (cfg, ks->num_peers, ks->peers, &msg->session_id,
1674 GNUNET_TIME_absolute_ntoh (msg->start),
1675 GNUNET_TIME_absolute_ntoh (msg->deadline),
1676 keygen_round1_new_element, ks);
1678 ks->info = GNUNET_new_array (ks->num_peers, struct KeygenPeerInfo);
1680 for (i = 0; i < ks->num_peers; i++)
1681 ks->info[i].peer = ks->peers[i];
1683 GNUNET_CRYPTO_paillier_create (&ks->info[ks->local_peer_idx].paillier_public_key,
1684 &ks->paillier_private_key);
1686 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Generated paillier key pair\n", ks->local_peer_idx);
1688 generate_presecret_polynomial (ks);
1690 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Generated presecret polynomial\n", ks->local_peer_idx);
1692 insert_round1_element (ks);
1694 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Concluding for round 1\n", ks->local_peer_idx);
1696 GNUNET_CONSENSUS_conclude (ks->consensus,
1697 keygen_round1_conclude,
1700 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1702 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Waiting for round 1 elements ...\n", ks->local_peer_idx);
1707 * Called when the partial decryption consensus concludes.
1710 decrypt_conclude (void *cls)
1712 struct DecryptSession *ds = cls;
1713 struct GNUNET_SECRETSHARING_DecryptResponseMessage *msg;
1714 struct GNUNET_MQ_Envelope *ev;
1715 gcry_mpi_t lagrange;
1720 unsigned int *indices;
1725 GNUNET_CONSENSUS_destroy (ds->consensus);
1726 ds->consensus = NULL;
1728 GNUNET_assert (0 != (lagrange = gcry_mpi_new (0)));
1729 GNUNET_assert (0 != (m = gcry_mpi_new (0)));
1730 GNUNET_assert (0 != (tmp = gcry_mpi_new (0)));
1731 GNUNET_assert (0 != (prod = gcry_mpi_new (0)));
1734 for (i = 0; i < ds->share->num_peers; i++)
1735 if (NULL != ds->info[i].partial_decryption)
1738 indices = GNUNET_malloc (num * sizeof (unsigned int));
1740 for (i = 0; i < ds->share->num_peers; i++)
1741 if (NULL != ds->info[i].partial_decryption)
1742 indices[j++] = ds->info[i].original_index;
1744 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "P%u: decrypt conclude, with %u peers\n",
1745 ds->share->my_peer, num);
1747 gcry_mpi_set_ui (prod, 1);
1748 for (i = 0; i < num; i++)
1751 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "P%u: index of %u: %u\n",
1752 ds->share->my_peer, i, indices[i]);
1753 compute_lagrange_coefficient (lagrange, indices[i], indices, num);
1755 gcry_mpi_powm (tmp, ds->info[indices[i]].partial_decryption, lagrange, elgamal_p);
1757 // product of all exponentiated partiel decryptions ...
1758 gcry_mpi_mulm (prod, prod, tmp, elgamal_p);
1761 GNUNET_CRYPTO_mpi_scan_unsigned (&c_2, ds->ciphertext.c2_bits, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1763 GNUNET_assert (0 != gcry_mpi_invm (prod, prod, elgamal_p));
1764 gcry_mpi_mulm (m, c_2, prod, elgamal_p);
1765 ev = GNUNET_MQ_msg (msg, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT_DONE);
1766 GNUNET_CRYPTO_mpi_print_unsigned (&msg->plaintext, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, m);
1767 msg->success = htonl (1);
1768 GNUNET_MQ_send (ds->client_mq, ev);
1770 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "sent decrypt done to client\n");
1772 GNUNET_free (indices);
1774 gcry_mpi_release(lagrange);
1775 gcry_mpi_release(m);
1776 gcry_mpi_release(tmp);
1777 gcry_mpi_release(prod);
1778 gcry_mpi_release(c_2);
1780 // FIXME: what if not enough peers participated?
1785 * Get a string representation of an MPI.
1786 * The caller must free the returned string.
1788 * @param mpi mpi to convert to a string
1789 * @return string representation of @a mpi, must be free'd by the caller
1792 mpi_to_str (gcry_mpi_t mpi)
1796 GNUNET_assert (0 == gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buf, NULL, mpi));
1797 return (char *) buf;
1802 * Called when a new partial decryption arrives.
1805 decrypt_new_element (void *cls,
1806 const struct GNUNET_SET_Element *element)
1808 struct DecryptSession *session = cls;
1809 const struct GNUNET_SECRETSHARING_DecryptData *d;
1810 struct DecryptPeerInfo *info;
1811 struct GNUNET_HashCode challenge_hash;
1815 /* nizk challenge */
1816 gcry_mpi_t challenge;
1817 /* nizk commit1, g^\beta */
1819 /* nizk commit2, c_1^\beta */
1821 /* homomorphic commitment to the peer's share,
1822 * public key share */
1824 /* partial decryption we received */
1826 /* ciphertext component #1 */
1828 /* temporary variable (for comparision) #1 */
1830 /* temporary variable (for comparision) #2 */
1833 if (NULL == element)
1835 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decryption failed\n");
1836 /* FIXME: destroy */
1840 if (element->size != sizeof *d)
1842 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "element of wrong size in decrypt consensus\n");
1848 info = get_decrypt_peer_info (session, &d->peer);
1852 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decrypt element from invalid peer (%s)\n",
1853 GNUNET_i2s (&d->peer));
1857 if (NULL != info->partial_decryption)
1859 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decrypt element duplicate\n",
1860 GNUNET_i2s (&d->peer));
1864 if (0 != memcmp (&d->ciphertext, &session->ciphertext, sizeof (struct GNUNET_SECRETSHARING_Ciphertext)))
1866 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: got decrypt element with non-matching ciphertext from P%u\n",
1867 (unsigned int) session->share->my_peer, (unsigned int) (info - session->info));
1873 GNUNET_CRYPTO_hash (offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext) + (char *) d,
1874 offsetof (struct GNUNET_SECRETSHARING_DecryptData, nizk_response) -
1875 offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext),
1878 GNUNET_CRYPTO_mpi_scan_unsigned (&challenge, &challenge_hash,
1879 sizeof (struct GNUNET_HashCode));
1881 GNUNET_CRYPTO_mpi_scan_unsigned (&sigma, &session->share->sigmas[info - session->info],
1882 sizeof (struct GNUNET_SECRETSHARING_FieldElement));
1884 GNUNET_CRYPTO_mpi_scan_unsigned (&c1, session->ciphertext.c1_bits,
1885 sizeof (struct GNUNET_SECRETSHARING_FieldElement));
1887 GNUNET_CRYPTO_mpi_scan_unsigned (&commit1, &d->nizk_commit1,
1888 sizeof (struct GNUNET_SECRETSHARING_FieldElement));
1890 GNUNET_CRYPTO_mpi_scan_unsigned (&commit2, &d->nizk_commit2,
1891 sizeof (struct GNUNET_SECRETSHARING_FieldElement));
1893 GNUNET_CRYPTO_mpi_scan_unsigned (&r, &d->nizk_response,
1894 sizeof (struct GNUNET_SECRETSHARING_FieldElement));
1896 GNUNET_CRYPTO_mpi_scan_unsigned (&w, &d->partial_decryption,
1897 sizeof (struct GNUNET_SECRETSHARING_FieldElement));
1899 GNUNET_assert (NULL != (tmp1 = gcry_mpi_new (0)));
1900 GNUNET_assert (NULL != (tmp2 = gcry_mpi_new (0)));
1903 gcry_mpi_powm (tmp1, elgamal_g, r, elgamal_p);
1905 // tmp2 = g^\beta * \sigma^challenge
1906 gcry_mpi_powm (tmp2, sigma, challenge, elgamal_p);
1907 gcry_mpi_mulm (tmp2, tmp2, commit1, elgamal_p);
1909 if (0 != gcry_mpi_cmp (tmp1, tmp2))
1913 tmp1_str = mpi_to_str (tmp1);
1914 tmp2_str = mpi_to_str (tmp2);
1915 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: Received invalid partial decryption from P%u (eqn 1), expected %s got %s\n",
1916 session->share->my_peer, info - session->info, tmp1_str, tmp2_str);
1917 GNUNET_free (tmp1_str);
1918 GNUNET_free (tmp2_str);
1923 gcry_mpi_powm (tmp1, c1, r, elgamal_p);
1925 gcry_mpi_powm (tmp2, w, challenge, elgamal_p);
1926 gcry_mpi_mulm (tmp2, tmp2, commit2, elgamal_p);
1929 if (0 != gcry_mpi_cmp (tmp1, tmp2))
1931 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: Received invalid partial decryption from P%u (eqn 2)\n",
1932 session->share->my_peer, info - session->info);
1937 GNUNET_CRYPTO_mpi_scan_unsigned (&info->partial_decryption, &d->partial_decryption,
1938 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1940 gcry_mpi_release (tmp1);
1941 gcry_mpi_release (tmp2);
1942 gcry_mpi_release (sigma);
1943 gcry_mpi_release (commit1);
1944 gcry_mpi_release (commit2);
1945 gcry_mpi_release (r);
1946 gcry_mpi_release (w);
1947 gcry_mpi_release (challenge);
1948 gcry_mpi_release (c1);
1953 insert_decrypt_element (struct DecryptSession *ds)
1955 struct GNUNET_SECRETSHARING_DecryptData d;
1956 struct GNUNET_SET_Element element;
1959 /* partial decryption with our share */
1961 /* first component of the elgamal ciphertext */
1963 /* nonce for dlog zkp */
1966 gcry_mpi_t challenge;
1968 struct GNUNET_HashCode challenge_hash;
1970 /* make vagrind happy until we implement the real deal ... */
1971 memset (&d, 0, sizeof d);
1973 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting decrypt element\n",
1974 ds->share->my_peer);
1976 GNUNET_assert (ds->share->my_peer < ds->share->num_peers);
1978 GNUNET_CRYPTO_mpi_scan_unsigned (&c1, &ds->ciphertext.c1_bits,
1979 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1980 GNUNET_CRYPTO_mpi_scan_unsigned (&s, &ds->share->my_share,
1981 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1982 GNUNET_CRYPTO_mpi_scan_unsigned (&sigma, &ds->share->sigmas[ds->share->my_peer],
1983 GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1985 GNUNET_assert (NULL != (w = gcry_mpi_new (0)));
1986 GNUNET_assert (NULL != (beta = gcry_mpi_new (0)));
1987 GNUNET_assert (NULL != (tmp = gcry_mpi_new (0)));
1989 // FIXME: unnecessary, remove once crypto works
1990 gcry_mpi_powm (tmp, elgamal_g, s, elgamal_p);
1991 if (0 != gcry_mpi_cmp (tmp, sigma))
1993 char *sigma_str = mpi_to_str (sigma);
1994 char *tmp_str = mpi_to_str (tmp);
1995 char *s_str = mpi_to_str (s);
1996 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Share of P%u is invalid, ref sigma %s, "
1997 "computed sigma %s, s %s\n",
1999 sigma_str, tmp_str, s_str);
2000 GNUNET_free (sigma_str);
2001 GNUNET_free (tmp_str);
2002 GNUNET_free (s_str);
2005 gcry_mpi_powm (w, c1, s, elgamal_p);
2007 element.data = (void *) &d;
2008 element.size = sizeof (struct GNUNET_SECRETSHARING_DecryptData);
2011 d.ciphertext = ds->ciphertext;
2013 GNUNET_CRYPTO_mpi_print_unsigned (&d.partial_decryption, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, w);
2015 // create the zero knowledge proof
2016 // randomly choose beta such that 0 < beta < q
2019 gcry_mpi_randomize (beta, GNUNET_SECRETSHARING_ELGAMAL_BITS - 1, GCRY_WEAK_RANDOM);
2020 } while ((gcry_mpi_cmp_ui (beta, 0) == 0) || (gcry_mpi_cmp (beta, elgamal_q) >= 0));
2022 gcry_mpi_powm (tmp, elgamal_g, beta, elgamal_p);
2023 GNUNET_CRYPTO_mpi_print_unsigned (&d.nizk_commit1, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, tmp);
2025 gcry_mpi_powm (tmp, c1, beta, elgamal_p);
2026 GNUNET_CRYPTO_mpi_print_unsigned (&d.nizk_commit2, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, tmp);
2028 // the challenge is the hash of everything up to the response
2029 GNUNET_CRYPTO_hash (offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext) + (char *) &d,
2030 offsetof (struct GNUNET_SECRETSHARING_DecryptData, nizk_response) -
2031 offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext),
2034 GNUNET_CRYPTO_mpi_scan_unsigned (&challenge, &challenge_hash,
2035 sizeof (struct GNUNET_HashCode));
2037 // compute the response in tmp,
2038 // tmp = (c * s + beta) mod q
2039 gcry_mpi_mulm (tmp, challenge, s, elgamal_q);
2040 gcry_mpi_addm (tmp, tmp, beta, elgamal_q);
2042 GNUNET_CRYPTO_mpi_print_unsigned (&d.nizk_response, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, tmp);
2044 d.purpose.size = htonl (element.size - offsetof (struct GNUNET_SECRETSHARING_DecryptData, purpose));
2045 d.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DECRYPTION);
2047 GNUNET_CRYPTO_eddsa_sign (my_peer_private_key, &d.purpose, &d.signature);
2049 GNUNET_CONSENSUS_insert (ds->consensus, &element, NULL, NULL);
2050 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting decrypt element done!\n",
2051 ds->share->my_peer);
2053 gcry_mpi_release (s);
2054 gcry_mpi_release (w);
2055 gcry_mpi_release (c1);
2056 gcry_mpi_release (beta);
2057 gcry_mpi_release (tmp);
2058 gcry_mpi_release (challenge);
2059 gcry_mpi_release (sigma);
2064 * Functions with this signature are called whenever a message is
2067 * @param cls closure
2068 * @param client identification of the client
2069 * @param message the actual message
2071 static void handle_client_decrypt (void *cls,
2072 struct GNUNET_SERVER_Client *client,
2073 const struct GNUNET_MessageHeader
2076 const struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg =
2077 (const void *) message;
2078 struct DecryptSession *ds;
2079 struct GNUNET_HashCode session_id;
2082 ds = GNUNET_new (struct DecryptSession);
2083 // FIXME: check if session already exists
2084 GNUNET_CONTAINER_DLL_insert (decrypt_sessions_head, decrypt_sessions_tail, ds);
2085 ds->client = client;
2086 ds->client_mq = GNUNET_MQ_queue_for_server_client (client);
2087 ds->start = GNUNET_TIME_absolute_ntoh (msg->start);
2088 ds->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
2089 ds->ciphertext = msg->ciphertext;
2091 ds->share = GNUNET_SECRETSHARING_share_read (&msg[1], ntohs (msg->header.size) - sizeof *msg, NULL);
2092 // FIXME: probably should be break rather than assert
2093 GNUNET_assert (NULL != ds->share);
2095 // FIXME: this is probably sufficient, but kdf/hash with all values would be nicer ...
2096 GNUNET_CRYPTO_hash (&msg->ciphertext, sizeof (struct GNUNET_SECRETSHARING_Ciphertext), &session_id);
2098 ds->consensus = GNUNET_CONSENSUS_create (cfg,
2099 ds->share->num_peers,
2104 &decrypt_new_element,
2108 ds->info = GNUNET_new_array (ds->share->num_peers, struct DecryptPeerInfo);
2109 for (i = 0; i < ds->share->num_peers; i++)
2111 ds->info[i].peer = ds->share->peers[i];
2112 ds->info[i].original_index = ds->share->original_indices[i];
2115 insert_decrypt_element (ds);
2117 GNUNET_CONSENSUS_conclude (ds->consensus, decrypt_conclude, ds);
2119 GNUNET_SERVER_receive_done (client, GNUNET_OK);
2121 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "decrypting with %u peers\n",
2122 ds->share->num_peers);
2127 init_crypto_constants (void)
2129 GNUNET_assert (0 == gcry_mpi_scan (&elgamal_q, GCRYMPI_FMT_HEX,
2130 GNUNET_SECRETSHARING_ELGAMAL_Q_HEX, 0, NULL));
2131 GNUNET_assert (0 == gcry_mpi_scan (&elgamal_p, GCRYMPI_FMT_HEX,
2132 GNUNET_SECRETSHARING_ELGAMAL_P_HEX, 0, NULL));
2133 GNUNET_assert (0 == gcry_mpi_scan (&elgamal_g, GCRYMPI_FMT_HEX,
2134 GNUNET_SECRETSHARING_ELGAMAL_G_HEX, 0, NULL));
2138 static struct KeygenSession *
2139 keygen_session_get (struct GNUNET_SERVER_Client *client)
2141 struct KeygenSession *ks;
2142 for (ks = keygen_sessions_head; NULL != ks; ks = ks->next)
2143 if (ks->client == client)
2148 static struct DecryptSession *
2149 decrypt_session_get (struct GNUNET_SERVER_Client *client)
2151 struct DecryptSession *ds;
2152 for (ds = decrypt_sessions_head; NULL != ds; ds = ds->next)
2153 if (ds->client == client)
2160 * Clean up after a client has disconnected
2162 * @param cls closure, unused
2163 * @param client the client to clean up after
2166 handle_client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
2168 struct KeygenSession *ks;
2169 struct DecryptSession *ds;
2171 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "handling client disconnect\n");
2173 ks = keygen_session_get (client);
2175 keygen_session_destroy (ks);
2177 ds = decrypt_session_get (client);
2179 decrypt_session_destroy (ds);
2184 * Process template requests.
2186 * @param cls closure
2187 * @param server the initialized server
2188 * @param c configuration to use
2191 run (void *cls, struct GNUNET_SERVER_Handle *server,
2192 const struct GNUNET_CONFIGURATION_Handle *c)
2194 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
2195 {handle_client_keygen, NULL, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_GENERATE, 0},
2196 {handle_client_decrypt, NULL, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT, 0},
2201 my_peer_private_key = GNUNET_CRYPTO_eddsa_key_create_from_configuration (c);
2202 if (NULL == my_peer_private_key)
2204 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not access host private key\n");
2206 GNUNET_SCHEDULER_shutdown ();
2209 init_crypto_constants ();
2210 if (GNUNET_OK != GNUNET_CRYPTO_get_peer_identity (cfg, &my_peer))
2212 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not retrieve host identity\n");
2214 GNUNET_SCHEDULER_shutdown ();
2217 GNUNET_SERVER_add_handlers (server, handlers);
2218 GNUNET_SERVER_disconnect_notify (server, &handle_client_disconnect, NULL);
2219 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleanup_task,
2225 * The main function for the template service.
2227 * @param argc number of arguments from the command line
2228 * @param argv command line arguments
2229 * @return 0 ok, 1 on error
2232 main (int argc, char *const *argv)
2234 return (GNUNET_OK ==
2235 GNUNET_SERVICE_run (argc, argv, "secretsharing",
2236 GNUNET_SERVICE_OPTION_NONE, &run, NULL)) ? 0 : 1;