GNUnet  0.19.2
gnunet-service-secretsharing.c
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1 /*
2  This file is part of GNUnet.
3  Copyright (C) 2013 GNUnet e.V.
4 
5  GNUnet is free software: you can redistribute it and/or modify it
6  under the terms of the GNU Affero General Public License as published
7  by the Free Software Foundation, either version 3 of the License,
8  or (at your option) any later version.
9 
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  Affero General Public License for more details.
14 
15  You should have received a copy of the GNU Affero General Public License
16  along with this program. If not, see <http://www.gnu.org/licenses/>.
17 
18  SPDX-License-Identifier: AGPL3.0-or-later
19  */
20 
26 #include "platform.h"
27 #include "gnunet_util_lib.h"
28 #include "gnunet_time_lib.h"
29 #include "gnunet_signatures.h"
31 #include "secretsharing.h"
32 #include "secretsharing_protocol.h"
33 #include <gcrypt.h>
34 
35 
36 #define EXTRA_CHECKS 1
37 
38 
43 {
48 
54 
59 
64  gcry_mpi_t preshare_commitment;
65 
69  gcry_mpi_t sigma;
70 
76 
82 };
83 
84 
89 {
94 
99  unsigned int original_index;
100 
107  gcry_mpi_t partial_decryption;
108 };
109 
110 
114 struct ClientState;
115 
116 
121 {
126 
130  struct ClientState *cs;
131 
141  gcry_mpi_t *presecret_polynomial;
142 
148  unsigned int threshold;
149 
153  unsigned int num_peers;
154 
158  unsigned int local_peer;
159 
165 
170 
175 
180 
185 
191 
196  unsigned int local_peer_idx;
197 
202  gcry_mpi_t my_share;
203 
207  gcry_mpi_t public_key;
208 };
209 
210 
215 {
220 
224  struct ClientState *cs;
225 
230 
236 
241 
248 
253 };
254 
255 
260 {
265 
270 
275 
280 };
281 
282 
287 static gcry_mpi_t elgamal_q;
288 
293 static gcry_mpi_t elgamal_p;
294 
299 static gcry_mpi_t elgamal_g;
300 
304 static struct GNUNET_PeerIdentity my_peer;
305 
310 
314 static const struct GNUNET_CONFIGURATION_Handle *cfg;
315 
316 
324 static struct KeygenPeerInfo *
326  const struct GNUNET_PeerIdentity *peer)
327 {
328  unsigned int i;
329 
330  for (i = 0; i < ks->num_peers; i++)
331  if (0 == GNUNET_memcmp (peer, &ks->info[i].peer))
332  return &ks->info[i];
333  return NULL;
334 }
335 
336 
344 static struct DecryptPeerInfo *
346  const struct GNUNET_PeerIdentity *peer)
347 {
348  unsigned int i;
349 
350  for (i = 0; i < ds->share->num_peers; i++)
351  if (0 == GNUNET_memcmp (peer, &ds->info[i].peer))
352  return &ds->info[i];
353  return NULL;
354 }
355 
356 
365 static struct GNUNET_TIME_Absolute
367  struct GNUNET_TIME_Absolute end,
368  int num, int denum)
369 {
371  uint64_t diff;
372 
373  GNUNET_assert (start.abs_value_us <= end.abs_value_us);
374  diff = end.abs_value_us - start.abs_value_us;
375  result.abs_value_us = start.abs_value_us + ((diff * num) / denum);
376 
377  return result;
378 }
379 
380 
388 static int
389 peer_id_cmp (const void *p1, const void *p2)
390 {
391  return memcmp (p1,
392  p2,
393  sizeof(struct GNUNET_PeerIdentity));
394 }
395 
396 
406 static int
407 peer_find (const struct GNUNET_PeerIdentity *haystack, unsigned int n,
408  const struct GNUNET_PeerIdentity *needle)
409 {
410  unsigned int i;
411 
412  for (i = 0; i < n; i++)
413  if (0 == GNUNET_memcmp (&haystack[i],
414  needle))
415  return i;
416  return -1;
417 }
418 
419 
430 static struct GNUNET_PeerIdentity *
432  unsigned int num_listed,
433  unsigned int *num_normalized,
434  unsigned int *my_peer_idx)
435 {
436  unsigned int local_peer_in_list;
437  /* number of peers in the normalized list */
438  unsigned int n;
439  struct GNUNET_PeerIdentity *normalized;
440 
441  local_peer_in_list = GNUNET_YES;
442  n = num_listed;
443  if (peer_find (listed, num_listed, &my_peer) < 0)
444  {
445  local_peer_in_list = GNUNET_NO;
446  n += 1;
447  }
448 
449  normalized = GNUNET_new_array (n,
450  struct GNUNET_PeerIdentity);
451 
452  if (GNUNET_NO == local_peer_in_list)
453  normalized[n - 1] = my_peer;
454 
455  GNUNET_memcpy (normalized,
456  listed,
457  num_listed * sizeof(struct GNUNET_PeerIdentity));
458  qsort (normalized,
459  n,
460  sizeof(struct GNUNET_PeerIdentity),
461  &peer_id_cmp);
462 
463  if (NULL != my_peer_idx)
464  *my_peer_idx = peer_find (normalized, n, &my_peer);
465  if (NULL != num_normalized)
466  *num_normalized = n;
467 
468  return normalized;
469 }
470 
471 
480 static void
481 compute_lagrange_coefficient (gcry_mpi_t coeff, unsigned int j,
482  unsigned int *indices,
483  unsigned int num)
484 {
485  unsigned int i;
486  /* numerator */
487  gcry_mpi_t n;
488  /* denominator */
489  gcry_mpi_t d;
490  /* temp value for l-j */
491  gcry_mpi_t tmp;
492 
493  GNUNET_assert (0 != coeff);
494 
495  GNUNET_assert (0 != (n = gcry_mpi_new (0)));
496  GNUNET_assert (0 != (d = gcry_mpi_new (0)));
497  GNUNET_assert (0 != (tmp = gcry_mpi_new (0)));
498 
499  gcry_mpi_set_ui (n, 1);
500  gcry_mpi_set_ui (d, 1);
501 
502  for (i = 0; i < num; i++)
503  {
504  unsigned int l = indices[i];
505  if (l == j)
506  continue;
507  gcry_mpi_mul_ui (n, n, l + 1);
508  // d <- d * (l-j)
509  gcry_mpi_set_ui (tmp, l + 1);
510  gcry_mpi_sub_ui (tmp, tmp, j + 1);
511  gcry_mpi_mul (d, d, tmp);
512  }
513 
514  // gcry_mpi_invm does not like negative numbers ...
515  gcry_mpi_mod (d, d, elgamal_q);
516 
517  GNUNET_assert (gcry_mpi_cmp_ui (d, 0) > 0);
518 
519  // now we do the actual division, with everything mod q, as we
520  // are not operating on elements from <g>, but on exponents
521  GNUNET_assert (0 != gcry_mpi_invm (d, d, elgamal_q));
522 
523  gcry_mpi_mulm (coeff, n, d, elgamal_q);
524 
525  gcry_mpi_release (n);
526  gcry_mpi_release (d);
527  gcry_mpi_release (tmp);
528 }
529 
530 
537 static void
539 {
541  "destroying decrypt session\n");
542  if (NULL != ds->cs)
543  {
544  ds->cs->decrypt_session = NULL;
545  ds->cs = NULL;
546  }
547  if (NULL != ds->consensus)
548  {
549  GNUNET_CONSENSUS_destroy (ds->consensus);
550  ds->consensus = NULL;
551  }
552 
553  if (NULL != ds->info)
554  {
555  for (unsigned int i = 0; i < ds->share->num_peers; i++)
556  {
557  if (NULL != ds->info[i].partial_decryption)
558  {
559  gcry_mpi_release (ds->info[i].partial_decryption);
560  ds->info[i].partial_decryption = NULL;
561  }
562  }
563  GNUNET_free (ds->info);
564  ds->info = NULL;
565  }
566  if (NULL != ds->share)
567  {
569  ds->share = NULL;
570  }
571 
572  GNUNET_free (ds);
573 }
574 
575 
576 static void
578 {
579  if (NULL != info->sigma)
580  {
581  gcry_mpi_release (info->sigma);
582  info->sigma = NULL;
583  }
584  if (NULL != info->presecret_commitment)
585  {
586  gcry_mpi_release (info->presecret_commitment);
587  info->presecret_commitment = NULL;
588  }
589  if (NULL != info->preshare_commitment)
590  {
591  gcry_mpi_release (info->preshare_commitment);
592  info->preshare_commitment = NULL;
593  }
594 }
595 
596 
597 static void
599 {
601  "destroying keygen session\n");
602 
603  if (NULL != ks->cs)
604  {
605  ks->cs->keygen_session = NULL;
606  ks->cs = NULL;
607  }
608  if (NULL != ks->info)
609  {
610  for (unsigned int i = 0; i < ks->num_peers; i++)
611  keygen_info_destroy (&ks->info[i]);
612  GNUNET_free (ks->info);
613  ks->info = NULL;
614  }
615 
616  if (NULL != ks->consensus)
617  {
619  ks->consensus = NULL;
620  }
621 
622  if (NULL != ks->presecret_polynomial)
623  {
624  for (unsigned int i = 0; i < ks->threshold; i++)
625  {
626  GNUNET_assert (NULL != ks->presecret_polynomial[i]);
627  gcry_mpi_release (ks->presecret_polynomial[i]);
628  ks->presecret_polynomial[i] = NULL;
629  }
631  ks->presecret_polynomial = NULL;
632  }
633  if (NULL != ks->my_share)
634  {
635  gcry_mpi_release (ks->my_share);
636  ks->my_share = NULL;
637  }
638  if (NULL != ks->public_key)
639  {
640  gcry_mpi_release (ks->public_key);
641  ks->public_key = NULL;
642  }
643  if (NULL != ks->peers)
644  {
645  GNUNET_free (ks->peers);
646  ks->peers = NULL;
647  }
648  GNUNET_free (ks);
649 }
650 
651 
657 static void
658 cleanup_task (void *cls)
659 {
660  /* Nothing to do! */
661 }
662 
663 
669 static void
671 {
672  int i;
673  gcry_mpi_t v;
674 
675  GNUNET_assert (NULL == ks->presecret_polynomial);
677  gcry_mpi_t);
678  for (i = 0; i < ks->threshold; i++)
679  {
680  v = ks->presecret_polynomial[i] = gcry_mpi_new (
682  GNUNET_assert (NULL != v);
683  // Randomize v such that 0 < v < elgamal_q.
684  // The '- 1' is necessary as bitlength(q) = bitlength(p) - 1.
685  do
686  {
687  gcry_mpi_randomize (v, GNUNET_SECRETSHARING_ELGAMAL_BITS - 1,
688  GCRY_WEAK_RANDOM);
689  }
690  while ((gcry_mpi_cmp_ui (v, 0) == 0) || (gcry_mpi_cmp (v, elgamal_q) >= 0));
691  }
692 }
693 
694 
703 static void
705  const struct GNUNET_SET_Element *element)
706 {
708  struct KeygenSession *ks = cls;
709  struct KeygenPeerInfo *info;
710 
711  if (NULL == element)
712  {
713  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "round1 consensus failed\n");
714  return;
715  }
716 
717  /* elements have fixed size */
718  if (element->size != sizeof(struct GNUNET_SECRETSHARING_KeygenCommitData))
719  {
721  "keygen commit data with wrong size (%u) in consensus, %u expected\n",
722  (unsigned int) element->size,
723  (unsigned int) sizeof(struct
725  return;
726  }
727 
728  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "got round1 element\n");
729 
730  d = element->data;
731  info = get_keygen_peer_info (ks, &d->peer);
732 
733  if (NULL == info)
734  {
736  "keygen commit data with wrong peer identity (%s) in consensus\n",
737  GNUNET_i2s (&d->peer));
738  return;
739  }
740 
741  /* Check that the right amount of data has been signed. */
742  if (d->purpose.size !=
743  htonl (element->size - offsetof (struct
745  purpose)))
746  {
748  "keygen commit data with wrong signature purpose size in consensus\n");
749  return;
750  }
751 
754  &d->purpose, &d->signature,
755  &d->peer.public_key))
756  {
758  "keygen commit data with invalid signature in consensus\n");
759  return;
760  }
761  info->paillier_public_key = d->pubkey;
762  GNUNET_CRYPTO_mpi_scan_unsigned (&info->presecret_commitment, &d->commitment,
763  512 / 8);
764  info->round1_valid = GNUNET_YES;
765 }
766 
767 
778 static void
779 horner_eval (gcry_mpi_t z, gcry_mpi_t *coeff, unsigned int num_coeff, gcry_mpi_t
780  x, gcry_mpi_t m)
781 {
782  unsigned int i;
783 
784  gcry_mpi_set_ui (z, 0);
785  for (i = 0; i < num_coeff; i++)
786  {
787  // z <- zx + c
788  gcry_mpi_mul (z, z, x);
789  gcry_mpi_addm (z, z, coeff[num_coeff - i - 1], m);
790  }
791 }
792 
793 
794 static void
796 {
797  struct KeygenSession *ks = cls;
799  struct GNUNET_MQ_Envelope *ev;
800  size_t share_size;
801  unsigned int i;
802  unsigned int j;
803  struct GNUNET_SECRETSHARING_Share *share;
804 
805  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "round2 conclude\n");
806 
808  ks->consensus = NULL;
809 
810  share = GNUNET_new (struct GNUNET_SECRETSHARING_Share);
811 
812  share->num_peers = 0;
813 
814  for (i = 0; i < ks->num_peers; i++)
815  if (GNUNET_YES == ks->info[i].round2_valid)
816  share->num_peers++;
817 
818  share->peers = GNUNET_new_array (share->num_peers,
819  struct GNUNET_PeerIdentity);
820  share->sigmas =
821  GNUNET_new_array (share->num_peers,
824  uint16_t);
825 
826  /* maybe we're not even in the list of peers? */
827  share->my_peer = share->num_peers;
828 
829  j = 0; /* running index of valid peers */
830  for (i = 0; i < ks->num_peers; i++)
831  {
832  if (GNUNET_YES == ks->info[i].round2_valid)
833  {
834  share->peers[j] = ks->info[i].peer;
837  ks->info[i].sigma);
838  share->original_indices[i] = j;
839  if (0 == GNUNET_memcmp (&share->peers[i], &my_peer))
840  share->my_peer = j;
841  j += 1;
842  }
843  }
844 
845  if (share->my_peer == share->num_peers)
846  {
847  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "P%u: peer identity not in share\n",
848  ks->local_peer_idx);
849  }
850 
853  ks->my_share);
856  ks->public_key);
857 
858  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "keygen completed with %u peers\n",
859  share->num_peers);
860 
861  /* Write the share. If 0 peers completed the dkg, an empty
862  * share will be sent. */
863 
865  &share_size));
866 
867  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "writing share of size %u\n",
868  (unsigned int) share_size);
869 
870  ev = GNUNET_MQ_msg_extra (m, share_size,
872 
874  share_size,
875  NULL));
876 
878  share = NULL;
879 
880  GNUNET_MQ_send (ks->cs->mq,
881  ev);
882 }
883 
884 
885 static void
887  const struct GNUNET_SECRETSHARING_FairEncryption *fe,
888  gcry_mpi_t x, gcry_mpi_t xres)
889 {
890  gcry_mpi_t a_1;
891  gcry_mpi_t a_2;
892  gcry_mpi_t b_1;
893  gcry_mpi_t b_2;
894  gcry_mpi_t big_a;
895  gcry_mpi_t big_b;
896  gcry_mpi_t big_t;
897  gcry_mpi_t n;
898  gcry_mpi_t t_1;
899  gcry_mpi_t t_2;
900  gcry_mpi_t t;
901  gcry_mpi_t r;
902  gcry_mpi_t v;
903 
904 
905  GNUNET_assert (NULL != (n = gcry_mpi_new (0)));
906  GNUNET_assert (NULL != (t = gcry_mpi_new (0)));
907  GNUNET_assert (NULL != (t_1 = gcry_mpi_new (0)));
908  GNUNET_assert (NULL != (t_2 = gcry_mpi_new (0)));
909  GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
910  GNUNET_assert (NULL != (big_t = gcry_mpi_new (0)));
911  GNUNET_assert (NULL != (v = gcry_mpi_new (0)));
912  GNUNET_assert (NULL != (big_a = gcry_mpi_new (0)));
913  GNUNET_assert (NULL != (big_b = gcry_mpi_new (0)));
914 
915  // a = (N,0)^T
917  ppub,
918  sizeof(struct
920  GNUNET_assert (NULL != (a_2 = gcry_mpi_new (0)));
921  gcry_mpi_set_ui (a_2, 0);
922  // b = (x,1)^T
923  GNUNET_assert (NULL != (b_1 = gcry_mpi_new (0)));
924  gcry_mpi_set (b_1, x);
925  GNUNET_assert (NULL != (b_2 = gcry_mpi_new (0)));
926  gcry_mpi_set_ui (b_2, 1);
927 
928  // A = a DOT a
929  gcry_mpi_mul (t, a_1, a_1);
930  gcry_mpi_mul (big_a, a_2, a_2);
931  gcry_mpi_add (big_a, big_a, t);
932 
933  // B = b DOT b
934  gcry_mpi_mul (t, b_1, b_1);
935  gcry_mpi_mul (big_b, b_2, b_2);
936  gcry_mpi_add (big_b, big_b, t);
937 
938  while (1)
939  {
940  // n = a DOT b
941  gcry_mpi_mul (t, a_1, b_1);
942  gcry_mpi_mul (n, a_2, b_2);
943  gcry_mpi_add (n, n, t);
944 
945  // r = nearest(n/B)
946  gcry_mpi_div (r, NULL, n, big_b, 0);
947 
948  // T := A - 2rn + rrB
949  gcry_mpi_mul (v, r, n);
950  gcry_mpi_mul_ui (v, v, 2);
951  gcry_mpi_sub (big_t, big_a, v);
952  gcry_mpi_mul (v, r, r);
953  gcry_mpi_mul (v, v, big_b);
954  gcry_mpi_add (big_t, big_t, v);
955 
956  if (gcry_mpi_cmp (big_t, big_b) >= 0)
957  {
958  break;
959  }
960 
961  // t = a - rb
962  gcry_mpi_mul (v, r, b_1);
963  gcry_mpi_sub (t_1, a_1, v);
964  gcry_mpi_mul (v, r, b_2);
965  gcry_mpi_sub (t_2, a_2, v);
966 
967  // a = b
968  gcry_mpi_set (a_1, b_1);
969  gcry_mpi_set (a_2, b_2);
970  // b = t
971  gcry_mpi_set (b_1, t_1);
972  gcry_mpi_set (b_2, t_2);
973 
974  gcry_mpi_set (big_a, big_b);
975  gcry_mpi_set (big_b, big_t);
976  }
977 
978  gcry_mpi_set (xres, b_2);
979  gcry_mpi_invm (xres, xres, elgamal_q);
980  gcry_mpi_mulm (xres, xres, b_1, elgamal_q);
981 
982  gcry_mpi_release (a_1);
983  gcry_mpi_release (a_2);
984  gcry_mpi_release (b_1);
985  gcry_mpi_release (b_2);
986  gcry_mpi_release (big_a);
987  gcry_mpi_release (big_b);
988  gcry_mpi_release (big_t);
989  gcry_mpi_release (n);
990  gcry_mpi_release (t_1);
991  gcry_mpi_release (t_2);
992  gcry_mpi_release (t);
993  gcry_mpi_release (r);
994  gcry_mpi_release (v);
995 }
996 
997 
998 static void
1001  gcry_mpi_t *e)
1002 {
1003  struct
1004  {
1007  char t1[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
1008  char t2[GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8];
1009  } hash_data;
1010  struct GNUNET_HashCode e_hash;
1011 
1012  memset (&hash_data,
1013  0,
1014  sizeof(hash_data));
1015  GNUNET_memcpy (&hash_data.c, &fe->c, sizeof(struct
1017  GNUNET_memcpy (&hash_data.h, &fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1018  GNUNET_memcpy (&hash_data.t1, &fe->t1, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
1019  GNUNET_memcpy (&hash_data.t2, &fe->t2, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
1020  GNUNET_CRYPTO_hash (&hash_data,
1021  sizeof(hash_data),
1022  &e_hash);
1023  /* This allocates "e" */
1025  &e_hash,
1026  sizeof(struct GNUNET_HashCode));
1027  gcry_mpi_mod (*e, *e, elgamal_q);
1028 }
1029 
1030 
1031 static int
1033  const struct GNUNET_SECRETSHARING_FairEncryption *fe)
1034 {
1035  gcry_mpi_t n;
1036  gcry_mpi_t n_sq;
1037  gcry_mpi_t z;
1038  gcry_mpi_t t1;
1039  gcry_mpi_t t2;
1040  gcry_mpi_t e;
1041  gcry_mpi_t w;
1042  gcry_mpi_t tmp1;
1043  gcry_mpi_t tmp2;
1044  gcry_mpi_t y;
1045  gcry_mpi_t big_y;
1046  int res;
1047 
1048  GNUNET_assert (NULL != (n_sq = gcry_mpi_new (0)));
1049  GNUNET_assert (NULL != (tmp1 = gcry_mpi_new (0)));
1050  GNUNET_assert (NULL != (tmp2 = gcry_mpi_new (0)));
1051 
1053  &e /* this allocates e */);
1054 
1056  ppub,
1057  sizeof(struct
1060  / 8);
1066  GNUNET_CRYPTO_mpi_scan_unsigned (&big_y, fe->c.bits,
1067  GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
1069  * 2 / 8);
1070  gcry_mpi_mul (n_sq, n, n);
1071 
1072  // tmp1 = g^z
1073  gcry_mpi_powm (tmp1, elgamal_g, z, elgamal_p);
1074  // tmp2 = y^{-e}
1075  gcry_mpi_powm (tmp1, y, e, elgamal_p);
1076  gcry_mpi_invm (tmp1, tmp1, elgamal_p);
1077  // tmp1 = tmp1 * tmp2
1078  gcry_mpi_mulm (tmp1, tmp1, tmp2, elgamal_p);
1079 
1080  if (0 == gcry_mpi_cmp (t1, tmp1))
1081  {
1082  GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "fair encryption invalid (t1)\n");
1083  res = GNUNET_NO;
1084  goto cleanup;
1085  }
1086 
1087  gcry_mpi_powm (big_y, big_y, e, n_sq);
1088  gcry_mpi_invm (big_y, big_y, n_sq);
1089 
1090  gcry_mpi_add_ui (tmp1, n, 1);
1091  gcry_mpi_powm (tmp1, tmp1, z, n_sq);
1092 
1093  gcry_mpi_powm (tmp2, w, n, n_sq);
1094 
1095  gcry_mpi_mulm (tmp1, tmp1, tmp2, n_sq);
1096  gcry_mpi_mulm (tmp1, tmp1, big_y, n_sq);
1097 
1098 
1099  if (0 == gcry_mpi_cmp (t2, tmp1))
1100  {
1101  GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "fair encryption invalid (t2)\n");
1102  res = GNUNET_NO;
1103  goto cleanup;
1104  }
1105 
1106  res = GNUNET_YES;
1107 
1108 cleanup:
1109 
1110  gcry_mpi_release (n);
1111  gcry_mpi_release (n_sq);
1112  gcry_mpi_release (z);
1113  gcry_mpi_release (t1);
1114  gcry_mpi_release (t2);
1115  gcry_mpi_release (e);
1116  gcry_mpi_release (w);
1117  gcry_mpi_release (tmp1);
1118  gcry_mpi_release (tmp2);
1119  gcry_mpi_release (y);
1120  gcry_mpi_release (big_y);
1121  return res;
1122 }
1123 
1124 
1131 static void
1132 encrypt_fair (gcry_mpi_t v,
1133  const struct GNUNET_CRYPTO_PaillierPublicKey *ppub,
1135 {
1136  gcry_mpi_t r;
1137  gcry_mpi_t s;
1138  gcry_mpi_t t1;
1139  gcry_mpi_t t2;
1140  gcry_mpi_t z;
1141  gcry_mpi_t w;
1142  gcry_mpi_t n;
1143  gcry_mpi_t e;
1144  gcry_mpi_t n_sq;
1145  gcry_mpi_t u;
1146  gcry_mpi_t Y;
1147  gcry_mpi_t G;
1148  gcry_mpi_t h;
1149 
1150  GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
1151  GNUNET_assert (NULL != (s = gcry_mpi_new (0)));
1152  GNUNET_assert (NULL != (t1 = gcry_mpi_new (0)));
1153  GNUNET_assert (NULL != (t2 = gcry_mpi_new (0)));
1154  GNUNET_assert (NULL != (z = gcry_mpi_new (0)));
1155  GNUNET_assert (NULL != (w = gcry_mpi_new (0)));
1156  GNUNET_assert (NULL != (n_sq = gcry_mpi_new (0)));
1157  GNUNET_assert (NULL != (u = gcry_mpi_new (0)));
1158  GNUNET_assert (NULL != (Y = gcry_mpi_new (0)));
1159  GNUNET_assert (NULL != (G = gcry_mpi_new (0)));
1160  GNUNET_assert (NULL != (h = gcry_mpi_new (0)));
1161 
1163  ppub,
1164  sizeof(struct
1166  gcry_mpi_mul (n_sq, n, n);
1167  gcry_mpi_add_ui (G, n, 1);
1168 
1169  do
1170  {
1171  gcry_mpi_randomize (u, GNUNET_CRYPTO_PAILLIER_BITS, GCRY_WEAK_RANDOM);
1172  }
1173  while (gcry_mpi_cmp (u, n) >= 0);
1174 
1175  gcry_mpi_powm (t1, G, v, n_sq);
1176  gcry_mpi_powm (t2, u, n, n_sq);
1177  gcry_mpi_mulm (Y, t1, t2, n_sq);
1178 
1180  sizeof fe->c.bits,
1181  Y);
1182 
1183 
1184  gcry_mpi_randomize (r, 2048, GCRY_WEAK_RANDOM);
1185  do
1186  {
1187  gcry_mpi_randomize (s, GNUNET_CRYPTO_PAILLIER_BITS, GCRY_WEAK_RANDOM);
1188  }
1189  while (gcry_mpi_cmp (s, n) >= 0);
1190 
1191  // compute t1
1192  gcry_mpi_mulm (t1, elgamal_g, r, elgamal_p);
1193  // compute t2 (use z and w as temp)
1194  gcry_mpi_powm (z, G, r, n_sq);
1195  gcry_mpi_powm (w, s, n, n_sq);
1196  gcry_mpi_mulm (t2, z, w, n_sq);
1197 
1198 
1199  gcry_mpi_powm (h, elgamal_g, v, elgamal_p);
1200 
1203  h);
1204 
1207  t1);
1208 
1211  t2);
1212 
1214  &e /* This allocates "e" */);
1215 
1216  // compute z
1217  gcry_mpi_mul (z, e, v);
1218  gcry_mpi_addm (z, z, r, elgamal_q);
1219  // compute w
1220  gcry_mpi_powm (w, u, e, n);
1221  gcry_mpi_mulm (w, w, s, n);
1222 
1225  z);
1226 
1229  w);
1230 
1231  gcry_mpi_release (n);
1232  gcry_mpi_release (r);
1233  gcry_mpi_release (s);
1234  gcry_mpi_release (t1);
1235  gcry_mpi_release (t2);
1236  gcry_mpi_release (z);
1237  gcry_mpi_release (w);
1238  gcry_mpi_release (e);
1239  gcry_mpi_release (n_sq);
1240  gcry_mpi_release (u);
1241  gcry_mpi_release (Y);
1242  gcry_mpi_release (G);
1243  gcry_mpi_release (h);
1244 }
1245 
1246 
1257 static void
1259 {
1260  struct GNUNET_SET_Element *element;
1262  unsigned char *pos;
1263  unsigned char *last_pos;
1264  size_t element_size;
1265  unsigned int i;
1266  gcry_mpi_t idx;
1267  gcry_mpi_t v;
1268 
1269  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting round2 element\n",
1270  ks->local_peer_idx);
1271 
1272  GNUNET_assert (NULL != (v = gcry_mpi_new (
1274  GNUNET_assert (NULL != (idx = gcry_mpi_new (
1276 
1278  + sizeof(struct GNUNET_SECRETSHARING_FairEncryption)
1279  * ks->num_peers
1281 
1282  element = GNUNET_malloc (sizeof(struct GNUNET_SET_Element) + element_size);
1283  element->size = element_size;
1284  element->data = (void *) &element[1];
1285 
1286  d = (void *) element->data;
1287  d->peer = my_peer;
1288 
1289  // start inserting vector elements
1290  // after the fixed part of the element's data
1291  pos = (void *) &d[1];
1292  last_pos = pos + element_size;
1293 
1294  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed exp preshares\n",
1295  ks->local_peer_idx);
1296 
1297  // encrypted pre-shares
1298  // and fair encryption proof
1299  {
1300  for (i = 0; i < ks->num_peers; i++)
1301  {
1302  ptrdiff_t remaining = last_pos - pos;
1303  struct GNUNET_SECRETSHARING_FairEncryption *fe = (void *) pos;
1304 
1305  GNUNET_assert (remaining > 0);
1306  memset (fe, 0, sizeof *fe);
1307  if (GNUNET_YES == ks->info[i].round1_valid)
1308  {
1309  gcry_mpi_set_ui (idx, i + 1);
1310  // evaluate the polynomial
1311  horner_eval (v, ks->presecret_polynomial, ks->threshold, idx,
1312  elgamal_q);
1313  // encrypt the result
1314  encrypt_fair (v, &ks->info[i].paillier_public_key, fe);
1315  }
1316  pos += sizeof *fe;
1317  }
1318  }
1319 
1320  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed enc preshares\n",
1321  ks->local_peer_idx);
1322 
1323  // exponentiated coefficients
1324  for (i = 0; i < ks->threshold; i++)
1325  {
1326  ptrdiff_t remaining = last_pos - pos;
1327  GNUNET_assert (remaining > 0);
1328  gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[i], elgamal_p);
1330  / 8, v);
1332  }
1333 
1334  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed exp coefficients\n",
1335  ks->local_peer_idx);
1336 
1337 
1338  d->purpose.size = htonl (element_size - offsetof (struct
1340  purpose));
1344  &d->purpose,
1345  &d->signature));
1346 
1347  GNUNET_CONSENSUS_insert (ks->consensus, element, NULL, NULL);
1348  GNUNET_free (element); /* FIXME: maybe stack-allocate instead? */
1349 
1350  gcry_mpi_release (v);
1351  gcry_mpi_release (idx);
1352 }
1353 
1354 
1355 static gcry_mpi_t
1357  const struct
1359  unsigned int idx)
1360 {
1361  unsigned char *pos;
1362  gcry_mpi_t exp_coeff;
1363 
1364  GNUNET_assert (idx < ks->threshold);
1365 
1366  pos = (void *) &d[1];
1367  // skip encrypted pre-shares
1368  pos += sizeof(struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers;
1369  // skip exp. coeffs we are not interested in
1370  pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * idx;
1371  // the first exponentiated coefficient is the public key share
1372  GNUNET_CRYPTO_mpi_scan_unsigned (&exp_coeff, pos,
1374  return exp_coeff;
1375 }
1376 
1377 
1380  const struct
1382  unsigned int idx)
1383 {
1384  unsigned char *pos;
1385 
1386  GNUNET_assert (idx < ks->num_peers);
1387 
1388  pos = (void *) &d[1];
1389  // skip encrypted pre-shares we're not interested in
1390  pos += sizeof(struct GNUNET_SECRETSHARING_FairEncryption) * idx;
1391  return (struct GNUNET_SECRETSHARING_FairEncryption *) pos;
1392 }
1393 
1394 
1395 static gcry_mpi_t
1397  const struct
1399  unsigned int idx)
1400 {
1401  gcry_mpi_t exp_preshare;
1403 
1404  GNUNET_assert (idx < ks->num_peers);
1405  fe = keygen_reveal_get_enc_preshare (ks, d, idx);
1406  GNUNET_CRYPTO_mpi_scan_unsigned (&exp_preshare, fe->h,
1408  return exp_preshare;
1409 }
1410 
1411 
1412 static void
1414  const struct GNUNET_SET_Element *element)
1415 {
1416  struct KeygenSession *ks = cls;
1417  const struct GNUNET_SECRETSHARING_KeygenRevealData *d;
1418  struct KeygenPeerInfo *info;
1419  size_t expected_element_size;
1420  unsigned int j;
1421  int cmp_result;
1422  gcry_mpi_t tmp;
1423  gcry_mpi_t public_key_share;
1424  gcry_mpi_t preshare;
1425 
1426  if (NULL == element)
1427  {
1428  GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "round2 consensus failed\n");
1429  return;
1430  }
1431 
1432  expected_element_size = (sizeof(struct GNUNET_SECRETSHARING_KeygenRevealData)
1433  + sizeof(struct
1435  * ks->num_peers
1437  * ks->threshold);
1438 
1439  if (element->size != expected_element_size)
1440  {
1442  "keygen round2 data with wrong size (%u) in consensus, %u expected\n",
1443  (unsigned int) element->size,
1444  (unsigned int) expected_element_size);
1445  return;
1446  }
1447 
1448  d = (const void *) element->data;
1449 
1450  info = get_keygen_peer_info (ks, &d->peer);
1451 
1452  if (NULL == info)
1453  {
1455  "keygen commit data with wrong peer identity (%s) in consensus\n",
1456  GNUNET_i2s (&d->peer));
1457  return;
1458  }
1459 
1460  if (GNUNET_NO == info->round1_valid)
1461  {
1463  "ignoring round2 element from peer with invalid round1 element (%s)\n",
1464  GNUNET_i2s (&d->peer));
1465  return;
1466  }
1467 
1468  if (GNUNET_YES == info->round2_valid)
1469  {
1471  "ignoring duplicate round2 element (%s)\n",
1472  GNUNET_i2s (&d->peer));
1473  return;
1474  }
1475 
1476  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "got round2 element\n");
1477 
1478  if (ntohl (d->purpose.size) !=
1479  element->size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData,
1480  purpose))
1481  {
1483  "keygen reveal data with wrong signature purpose size in consensus\n");
1484  return;
1485  }
1486 
1489  &d->purpose, &d->signature,
1490  &d->peer.public_key))
1491  {
1493  "keygen reveal data with invalid signature in consensus\n");
1494  return;
1495  }
1496 
1497  public_key_share = keygen_reveal_get_exp_coeff (ks, d, 0);
1498  info->preshare_commitment = keygen_reveal_get_exp_preshare (ks, d,
1499  ks->local_peer_idx);
1500 
1501  if (NULL == ks->public_key)
1502  {
1503  GNUNET_assert (NULL != (ks->public_key = gcry_mpi_new (0)));
1504  gcry_mpi_set_ui (ks->public_key, 1);
1505  }
1506  gcry_mpi_mulm (ks->public_key, ks->public_key, public_key_share, elgamal_p);
1507 
1508  gcry_mpi_release (public_key_share);
1509  public_key_share = NULL;
1510 
1511  {
1514  GNUNET_assert (NULL != (preshare = gcry_mpi_new (0)));
1516  &ks->info[ks->local_peer_idx].
1517  paillier_public_key,
1518  &fe->c,
1519  preshare);
1520 
1521  // FIXME: not doing the restoration is less expensive
1523  fe,
1524  preshare,
1525  preshare);
1526  }
1527 
1528  GNUNET_assert (NULL != (tmp = gcry_mpi_new (0)));
1529  gcry_mpi_powm (tmp, elgamal_g, preshare, elgamal_p);
1530 
1531  cmp_result = gcry_mpi_cmp (tmp, info->preshare_commitment);
1532  gcry_mpi_release (tmp);
1533  tmp = NULL;
1534  if (0 != cmp_result)
1535  {
1537  "P%u: Got invalid presecret from P%u\n",
1538  (unsigned int) ks->local_peer_idx, (unsigned int) (info
1539  - ks->info));
1540  return;
1541  }
1542 
1543  if (NULL == ks->my_share)
1544  {
1545  GNUNET_assert (NULL != (ks->my_share = gcry_mpi_new (0)));
1546  }
1547  gcry_mpi_addm (ks->my_share, ks->my_share, preshare, elgamal_q);
1548 
1549  for (j = 0; j < ks->num_peers; j++)
1550  {
1551  gcry_mpi_t presigma;
1552  if (NULL == ks->info[j].sigma)
1553  {
1554  GNUNET_assert (NULL != (ks->info[j].sigma = gcry_mpi_new (0)));
1555  gcry_mpi_set_ui (ks->info[j].sigma, 1);
1556  }
1557  presigma = keygen_reveal_get_exp_preshare (ks, d, j);
1558  gcry_mpi_mulm (ks->info[j].sigma, ks->info[j].sigma, presigma, elgamal_p);
1559  gcry_mpi_release (presigma);
1560  }
1561 
1562  gcry_mpi_t prod;
1563  GNUNET_assert (NULL != (prod = gcry_mpi_new (0)));
1564  gcry_mpi_t j_to_k;
1565  GNUNET_assert (NULL != (j_to_k = gcry_mpi_new (0)));
1566  // validate that the polynomial sharing matches the additive sharing
1567  for (j = 0; j < ks->num_peers; j++)
1568  {
1569  unsigned int k;
1570  int cmp_result;
1571  gcry_mpi_t exp_preshare;
1572  gcry_mpi_set_ui (prod, 1);
1573  for (k = 0; k < ks->threshold; k++)
1574  {
1575  // Using pow(double,double) is a bit sketchy.
1576  // We count players from 1, but shares from 0.
1577  gcry_mpi_t tmp;
1578  gcry_mpi_set_ui (j_to_k, (unsigned int) pow (j + 1, k));
1579  tmp = keygen_reveal_get_exp_coeff (ks, d, k);
1580  gcry_mpi_powm (tmp, tmp, j_to_k, elgamal_p);
1581  gcry_mpi_mulm (prod, prod, tmp, elgamal_p);
1582  gcry_mpi_release (tmp);
1583  }
1584  exp_preshare = keygen_reveal_get_exp_preshare (ks, d, j);
1585  gcry_mpi_mod (exp_preshare, exp_preshare, elgamal_p);
1586  cmp_result = gcry_mpi_cmp (prod, exp_preshare);
1587  gcry_mpi_release (exp_preshare);
1588  exp_preshare = NULL;
1589  if (0 != cmp_result)
1590  {
1592  "P%u: reveal data from P%u incorrect\n",
1593  ks->local_peer_idx, j);
1594  /* no need for further verification, round2 stays invalid ... */
1595  return;
1596  }
1597  }
1598 
1599  // TODO: verify proof of fair encryption (once implemented)
1600  for (j = 0; j < ks->num_peers; j++)
1601  {
1603  keygen_reveal_get_enc_preshare (ks, d, j);
1604  if (GNUNET_YES != verify_fair (&ks->info[j].paillier_public_key, fe))
1605  {
1607  "P%u: reveal data from P%u incorrect (fair encryption)\n",
1608  ks->local_peer_idx, j);
1609  return;
1610  }
1611  }
1612 
1613  info->round2_valid = GNUNET_YES;
1614 
1615  gcry_mpi_release (preshare);
1616  gcry_mpi_release (prod);
1617  gcry_mpi_release (j_to_k);
1618 }
1619 
1620 
1627 static void
1629 {
1630  struct KeygenSession *ks = cls;
1631 
1633 
1635  &ks->session_id,
1636  time_between (ks->start_time,
1637  ks->deadline, 1, 2),
1638  ks->deadline,
1640 
1641  insert_round2_element (ks);
1642 
1645  ks);
1646 }
1647 
1648 
1655 static void
1657 {
1658  struct GNUNET_SET_Element *element;
1660  // g^a_{i,0}
1661  gcry_mpi_t v;
1662  // big-endian representation of 'v'
1663  unsigned char v_data[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
1664 
1665  element = GNUNET_malloc (sizeof *element + sizeof *d);
1666  d = (void *) &element[1];
1667  element->data = d;
1668  element->size = sizeof *d;
1669 
1670  d->peer = my_peer;
1671 
1672  GNUNET_assert (0 != (v = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
1673 
1674  gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[0], elgamal_p);
1675 
1677  / 8, v);
1678 
1680  &d->commitment);
1681 
1683 
1684  d->purpose.size = htonl ((sizeof *d) - offsetof (struct
1686  purpose));
1690  &d->purpose,
1691  &d->signature));
1692 
1693  GNUNET_CONSENSUS_insert (ks->consensus, element, NULL, NULL);
1694 
1695  gcry_mpi_release (v);
1696  GNUNET_free (element);
1697 }
1698 
1699 
1707 static int
1710 {
1711  unsigned int num_peers = ntohs (msg->num_peers);
1712 
1713  if (ntohs (msg->header.size) - sizeof(*msg) !=
1714  num_peers * sizeof(struct GNUNET_PeerIdentity))
1715  {
1716  GNUNET_break (0);
1717  return GNUNET_SYSERR;
1718  }
1719  return GNUNET_OK;
1720 }
1721 
1722 
1730 static void
1733 {
1734  struct ClientState *cs = cls;
1735  struct KeygenSession *ks;
1736 
1738  "client requested key generation\n");
1739  if (NULL != cs->keygen_session)
1740  {
1741  GNUNET_break (0);
1743  return;
1744  }
1745  ks = GNUNET_new (struct KeygenSession);
1746  ks->cs = cs;
1747  cs->keygen_session = ks;
1748  ks->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
1749  ks->threshold = ntohs (msg->threshold);
1750  ks->num_peers = ntohs (msg->num_peers);
1751 
1752  ks->peers = normalize_peers ((struct GNUNET_PeerIdentity *) &msg[1],
1753  ks->num_peers,
1754  &ks->num_peers,
1755  &ks->local_peer_idx);
1756 
1757 
1759  "first round of consensus with %u peers\n",
1760  ks->num_peers);
1762  ks->num_peers,
1763  ks->peers,
1764  &msg->session_id,
1766  msg->start),
1768  msg->deadline),
1770  ks);
1771 
1772  ks->info = GNUNET_new_array (ks->num_peers,
1773  struct KeygenPeerInfo);
1774 
1775  for (unsigned int i = 0; i < ks->num_peers; i++)
1776  ks->info[i].peer = ks->peers[i];
1777 
1780  &ks->paillier_private_key);
1781 
1783  "P%u: Generated paillier key pair\n",
1784  ks->local_peer_idx);
1787  "P%u: Generated presecret polynomial\n",
1788  ks->local_peer_idx);
1789  insert_round1_element (ks);
1791  "P%u: Concluding for round 1\n",
1792  ks->local_peer_idx);
1795  ks);
1798  "P%u: Waiting for round 1 elements ...\n",
1799  ks->local_peer_idx);
1800 }
1801 
1802 
1806 static void
1807 decrypt_conclude (void *cls)
1808 {
1809  struct DecryptSession *ds = cls;
1811  struct GNUNET_MQ_Envelope *ev;
1812  gcry_mpi_t lagrange;
1813  gcry_mpi_t m;
1814  gcry_mpi_t tmp;
1815  gcry_mpi_t c_2;
1816  gcry_mpi_t prod;
1817  unsigned int *indices;
1818  unsigned int num;
1819  unsigned int i;
1820  unsigned int j;
1821 
1822  GNUNET_CONSENSUS_destroy (ds->consensus);
1823  ds->consensus = NULL;
1824 
1825  GNUNET_assert (0 != (lagrange = gcry_mpi_new (0)));
1826  GNUNET_assert (0 != (m = gcry_mpi_new (0)));
1827  GNUNET_assert (0 != (tmp = gcry_mpi_new (0)));
1828  GNUNET_assert (0 != (prod = gcry_mpi_new (0)));
1829 
1830  num = 0;
1831  for (i = 0; i < ds->share->num_peers; i++)
1832  if (NULL != ds->info[i].partial_decryption)
1833  num++;
1834 
1835  indices = GNUNET_new_array (num,
1836  unsigned int);
1837  j = 0;
1838  for (i = 0; i < ds->share->num_peers; i++)
1839  if (NULL != ds->info[i].partial_decryption)
1840  indices[j++] = ds->info[i].original_index;
1841 
1843  "P%u: decrypt conclude, with %u peers\n",
1844  ds->share->my_peer,
1845  num);
1846 
1847  gcry_mpi_set_ui (prod, 1);
1848  for (i = 0; i < num; i++)
1849  {
1851  "P%u: index of %u: %u\n",
1852  ds->share->my_peer, i, indices[i]);
1853  compute_lagrange_coefficient (lagrange, indices[i], indices, num);
1854  // w_i^{\lambda_i}
1855  gcry_mpi_powm (tmp, ds->info[indices[i]].partial_decryption, lagrange,
1856  elgamal_p);
1857 
1858  // product of all exponentiated partiel decryptions ...
1859  gcry_mpi_mulm (prod, prod, tmp, elgamal_p);
1860  }
1861 
1862  GNUNET_CRYPTO_mpi_scan_unsigned (&c_2, ds->ciphertext.c2_bits,
1864 
1865  GNUNET_assert (0 != gcry_mpi_invm (prod, prod, elgamal_p));
1866  gcry_mpi_mulm (m, c_2, prod, elgamal_p);
1867  ev = GNUNET_MQ_msg (msg,
1871  msg->success = htonl (1);
1872  GNUNET_MQ_send (ds->cs->mq,
1873  ev);
1874 
1875  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "sent decrypt done to client\n");
1876 
1877  GNUNET_free (indices);
1878 
1879  gcry_mpi_release (lagrange);
1880  gcry_mpi_release (m);
1881  gcry_mpi_release (tmp);
1882  gcry_mpi_release (prod);
1883  gcry_mpi_release (c_2);
1884 
1885  // FIXME: what if not enough peers participated?
1886 }
1887 
1888 
1896 static char *
1897 mpi_to_str (gcry_mpi_t mpi)
1898 {
1899  unsigned char *buf;
1900 
1901  GNUNET_assert (0 == gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buf, NULL, mpi));
1902  return (char *) buf;
1903 }
1904 
1905 
1909 static void
1911  const struct GNUNET_SET_Element *element)
1912 {
1913  struct DecryptSession *session = cls;
1914  const struct GNUNET_SECRETSHARING_DecryptData *d;
1915  struct DecryptPeerInfo *info;
1916  struct GNUNET_HashCode challenge_hash;
1917 
1918  /* nizk response */
1919  gcry_mpi_t r;
1920  /* nizk challenge */
1921  gcry_mpi_t challenge;
1922  /* nizk commit1, g^\beta */
1923  gcry_mpi_t commit1;
1924  /* nizk commit2, c_1^\beta */
1925  gcry_mpi_t commit2;
1926  /* homomorphic commitment to the peer's share,
1927  * public key share */
1928  gcry_mpi_t sigma;
1929  /* partial decryption we received */
1930  gcry_mpi_t w;
1931  /* ciphertext component #1 */
1932  gcry_mpi_t c1;
1933  /* temporary variable (for comparison) #1 */
1934  gcry_mpi_t tmp1;
1935  /* temporary variable (for comparison) #2 */
1936  gcry_mpi_t tmp2;
1937 
1938  if (NULL == element)
1939  {
1940  GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decryption failed\n");
1941  /* FIXME: destroy */
1942  return;
1943  }
1944 
1945  if (element->size != sizeof *d)
1946  {
1948  "element of wrong size in decrypt consensus\n");
1949  return;
1950  }
1951 
1952  d = element->data;
1953 
1954  info = get_decrypt_peer_info (session, &d->peer);
1955 
1956  if (NULL == info)
1957  {
1959  "decrypt element from invalid peer (%s)\n",
1960  GNUNET_i2s (&d->peer));
1961  return;
1962  }
1963 
1964  if (NULL != info->partial_decryption)
1965  {
1966  GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decrypt element duplicate\n");
1967  return;
1968  }
1969 
1970  if (0 != GNUNET_memcmp (&d->ciphertext, &session->ciphertext))
1971  {
1973  "P%u: got decrypt element with non-matching ciphertext from P%u\n",
1974  (unsigned int) session->share->my_peer, (unsigned int) (info
1975  -
1976  session
1977  ->info));
1978 
1979  return;
1980  }
1981 
1982 
1984  ciphertext) + (char *) d,
1985  offsetof (struct GNUNET_SECRETSHARING_DecryptData,
1986  nizk_response)
1987  - offsetof (struct GNUNET_SECRETSHARING_DecryptData,
1988  ciphertext),
1989  &challenge_hash);
1990 
1991  GNUNET_CRYPTO_mpi_scan_unsigned (&challenge, &challenge_hash,
1992  sizeof(struct GNUNET_HashCode));
1993 
1994  GNUNET_CRYPTO_mpi_scan_unsigned (&sigma, &session->share->sigmas[info
1995  - session->
1996  info],
1997  sizeof(struct
1999 
2001  sizeof(struct
2003 
2005  sizeof(struct
2007 
2009  sizeof(struct
2011 
2013  sizeof(struct
2015 
2017  sizeof(struct
2019 
2020  GNUNET_assert (NULL != (tmp1 = gcry_mpi_new (0)));
2021  GNUNET_assert (NULL != (tmp2 = gcry_mpi_new (0)));
2022 
2023  // tmp1 = g^r
2024  gcry_mpi_powm (tmp1, elgamal_g, r, elgamal_p);
2025 
2026  // tmp2 = g^\beta * \sigma^challenge
2027  gcry_mpi_powm (tmp2, sigma, challenge, elgamal_p);
2028  gcry_mpi_mulm (tmp2, tmp2, commit1, elgamal_p);
2029 
2030  if (0 != gcry_mpi_cmp (tmp1, tmp2))
2031  {
2032  char *tmp1_str;
2033  char *tmp2_str;
2034 
2035  tmp1_str = mpi_to_str (tmp1);
2036  tmp2_str = mpi_to_str (tmp2);
2038  "P%u: Received invalid partial decryption from P%u (eqn 1), expected %s got %s\n",
2039  session->share->my_peer,
2040  (unsigned int) (info - session->info),
2041  tmp1_str,
2042  tmp2_str);
2043  GNUNET_free (tmp1_str);
2044  GNUNET_free (tmp2_str);
2045  goto cleanup;
2046  }
2047 
2048 
2049  gcry_mpi_powm (tmp1, c1, r, elgamal_p);
2050 
2051  gcry_mpi_powm (tmp2, w, challenge, elgamal_p);
2052  gcry_mpi_mulm (tmp2, tmp2, commit2, elgamal_p);
2053 
2054 
2055  if (0 != gcry_mpi_cmp (tmp1, tmp2))
2056  {
2058  "P%u: Received invalid partial decryption from P%u (eqn 2)\n",
2059  session->share->my_peer,
2060  (unsigned int) (info - session->info));
2061  goto cleanup;
2062  }
2063 
2064 
2065  GNUNET_CRYPTO_mpi_scan_unsigned (&info->partial_decryption,
2066  &d->partial_decryption,
2068 cleanup:
2069  gcry_mpi_release (tmp1);
2070  gcry_mpi_release (tmp2);
2071  gcry_mpi_release (sigma);
2072  gcry_mpi_release (commit1);
2073  gcry_mpi_release (commit2);
2074  gcry_mpi_release (r);
2075  gcry_mpi_release (w);
2076  gcry_mpi_release (challenge);
2077  gcry_mpi_release (c1);
2078 }
2079 
2080 
2081 static void
2083 {
2085  struct GNUNET_SET_Element element;
2086  /* our share */
2087  gcry_mpi_t s;
2088  /* partial decryption with our share */
2089  gcry_mpi_t w;
2090  /* first component of the elgamal ciphertext */
2091  gcry_mpi_t c1;
2092  /* nonce for dlog zkp */
2093  gcry_mpi_t beta;
2094  gcry_mpi_t tmp;
2095  gcry_mpi_t challenge;
2096  gcry_mpi_t sigma;
2097  struct GNUNET_HashCode challenge_hash;
2098 
2099  /* make vagrind happy until we implement the real deal ... */
2100  memset (&d, 0, sizeof d);
2101 
2102  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting decrypt element\n",
2103  ds->share->my_peer);
2104 
2105  GNUNET_assert (ds->share->my_peer < ds->share->num_peers);
2106 
2107  GNUNET_CRYPTO_mpi_scan_unsigned (&c1, &ds->ciphertext.c1_bits,
2109  GNUNET_CRYPTO_mpi_scan_unsigned (&s, &ds->share->my_share,
2112  &ds->share->sigmas[ds->share->my_peer],
2114 
2115  GNUNET_assert (NULL != (w = gcry_mpi_new (0)));
2116  GNUNET_assert (NULL != (beta = gcry_mpi_new (0)));
2117  GNUNET_assert (NULL != (tmp = gcry_mpi_new (0)));
2118 
2119  // FIXME: unnecessary, remove once crypto works
2120  gcry_mpi_powm (tmp, elgamal_g, s, elgamal_p);
2121  if (0 != gcry_mpi_cmp (tmp, sigma))
2122  {
2123  char *sigma_str = mpi_to_str (sigma);
2124  char *tmp_str = mpi_to_str (tmp);
2125  char *s_str = mpi_to_str (s);
2127  "Share of P%u is invalid, ref sigma %s, "
2128  "computed sigma %s, s %s\n",
2129  ds->share->my_peer,
2130  sigma_str, tmp_str, s_str);
2131  GNUNET_free (sigma_str);
2132  GNUNET_free (tmp_str);
2133  GNUNET_free (s_str);
2134  }
2135 
2136  gcry_mpi_powm (w, c1, s, elgamal_p);
2137 
2138  element.data = (void *) &d;
2139  element.size = sizeof(struct GNUNET_SECRETSHARING_DecryptData);
2140  element.element_type = 0;
2141 
2142  d.ciphertext = ds->ciphertext;
2143  d.peer = my_peer;
2146 
2147  // create the zero knowledge proof
2148  // randomly choose beta such that 0 < beta < q
2149  do
2150  {
2151  gcry_mpi_randomize (beta, GNUNET_SECRETSHARING_ELGAMAL_BITS - 1,
2152  GCRY_WEAK_RANDOM);
2153  }
2154  while ((gcry_mpi_cmp_ui (beta, 0) == 0) || (gcry_mpi_cmp (beta, elgamal_q) >=
2155  0));
2156  // tmp = g^beta
2157  gcry_mpi_powm (tmp, elgamal_g, beta, elgamal_p);
2160  // tmp = (c_1)^beta
2161  gcry_mpi_powm (tmp, c1, beta, elgamal_p);
2164 
2165  // the challenge is the hash of everything up to the response
2167  ciphertext) + (char *) &d,
2168  offsetof (struct GNUNET_SECRETSHARING_DecryptData,
2169  nizk_response)
2170  - offsetof (struct GNUNET_SECRETSHARING_DecryptData,
2171  ciphertext),
2172  &challenge_hash);
2173 
2174  GNUNET_CRYPTO_mpi_scan_unsigned (&challenge, &challenge_hash,
2175  sizeof(struct GNUNET_HashCode));
2176 
2177  // compute the response in tmp,
2178  // tmp = (c * s + beta) mod q
2179  gcry_mpi_mulm (tmp, challenge, s, elgamal_q);
2180  gcry_mpi_addm (tmp, tmp, beta, elgamal_q);
2181 
2184 
2185  d.purpose.size = htonl (element.size - offsetof (struct
2187  purpose));
2189 
2192  &d.purpose,
2193  &d.signature));
2194 
2195  GNUNET_CONSENSUS_insert (ds->consensus, &element, NULL, NULL);
2197  "P%u: Inserting decrypt element done!\n",
2198  ds->share->my_peer);
2199 
2200  gcry_mpi_release (s);
2201  gcry_mpi_release (w);
2202  gcry_mpi_release (c1);
2203  gcry_mpi_release (beta);
2204  gcry_mpi_release (tmp);
2205  gcry_mpi_release (challenge);
2206  gcry_mpi_release (sigma);
2207 }
2208 
2209 
2217 static int
2219  const struct
2221 {
2222  /* we check later, it's complicated */
2223  return GNUNET_OK;
2224 }
2225 
2226 
2234 static void
2236  const struct
2238 {
2239  struct ClientState *cs = cls;
2240  struct DecryptSession *ds;
2241  struct GNUNET_HashCode session_id;
2242 
2243  if (NULL != cs->decrypt_session)
2244  {
2245  GNUNET_break (0);
2247  return;
2248  }
2249  ds = GNUNET_new (struct DecryptSession);
2250  cs->decrypt_session = ds;
2251  ds->cs = cs;
2252  ds->start = GNUNET_TIME_absolute_ntoh (msg->start);
2253  ds->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
2254  ds->ciphertext = msg->ciphertext;
2255 
2256  ds->share = GNUNET_SECRETSHARING_share_read (&msg[1],
2257  ntohs (msg->header.size)
2258  - sizeof(*msg),
2259  NULL);
2260  if (NULL == ds->share)
2261  {
2262  GNUNET_break (0);
2264  return;
2265  }
2266 
2267  /* FIXME: this is probably sufficient, but kdf/hash with all values would be nicer ... */
2268  GNUNET_CRYPTO_hash (&msg->ciphertext,
2269  sizeof(struct GNUNET_SECRETSHARING_Ciphertext),
2270  &session_id);
2271  ds->consensus = GNUNET_CONSENSUS_create (cfg,
2272  ds->share->num_peers,
2273  ds->share->peers,
2274  &session_id,
2275  ds->start,
2276  ds->deadline,
2278  ds);
2279 
2280 
2281  ds->info = GNUNET_new_array (ds->share->num_peers,
2282  struct DecryptPeerInfo);
2283  for (unsigned int i = 0; i < ds->share->num_peers; i++)
2284  {
2285  ds->info[i].peer = ds->share->peers[i];
2286  ds->info[i].original_index = ds->share->original_indices[i];
2287  }
2289  GNUNET_CONSENSUS_conclude (ds->consensus,
2291  ds);
2294  "decrypting with %u peers\n",
2295  ds->share->num_peers);
2296 }
2297 
2298 
2299 static void
2301 {
2302  GNUNET_assert (0 == gcry_mpi_scan (&elgamal_q, GCRYMPI_FMT_HEX,
2304  NULL));
2305  GNUNET_assert (0 == gcry_mpi_scan (&elgamal_p, GCRYMPI_FMT_HEX,
2307  NULL));
2308  GNUNET_assert (0 == gcry_mpi_scan (&elgamal_g, GCRYMPI_FMT_HEX,
2310  NULL));
2311 }
2312 
2313 
2321 static void
2322 run (void *cls,
2323  const struct GNUNET_CONFIGURATION_Handle *c,
2325 {
2326  cfg = c;
2328  if (NULL == my_peer_private_key)
2329  {
2331  "could not access host private key\n");
2332  GNUNET_break (0);
2334  return;
2335  }
2337  if (GNUNET_OK !=
2339  &my_peer))
2340  {
2342  "could not retrieve host identity\n");
2343  GNUNET_break (0);
2345  return;
2346  }
2348  NULL);
2349 }
2350 
2351 
2360 static void *
2362  struct GNUNET_SERVICE_Client *c,
2363  struct GNUNET_MQ_Handle *mq)
2364 {
2365  struct ClientState *cs = GNUNET_new (struct ClientState);;
2366 
2367  cs->client = c;
2368  cs->mq = mq;
2369  return cs;
2370 }
2371 
2372 
2380 static void
2382  struct GNUNET_SERVICE_Client *c,
2383  void *internal_cls)
2384 {
2385  struct ClientState *cs = internal_cls;
2386 
2387  if (NULL != cs->keygen_session)
2389 
2390  if (NULL != cs->decrypt_session)
2392  GNUNET_free (cs);
2393 }
2394 
2395 
2400  ("secretsharing",
2402  &run,
2405  NULL,
2406  GNUNET_MQ_hd_var_size (client_keygen,
2409  NULL),
2410  GNUNET_MQ_hd_var_size (client_decrypt,
2413  NULL),
struct GNUNET_MQ_Handle * mq
Definition: 003.c:5
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
#define GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG2
Signature for the second round of distributed key generation.
#define GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG1
Signature for the first round of distributed key generation.
#define GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DECRYPTION
Signature for the cooperative decryption.
static struct GNUNET_ARM_MonitorHandle * m
Monitor connection with ARM.
Definition: gnunet-arm.c:104
static struct GNUNET_ARM_Handle * h
Connection with ARM.
Definition: gnunet-arm.c:99
static int start
Set if we are to start default services (including ARM).
Definition: gnunet-arm.c:39
static int end
Set if we are to shutdown all services (including ARM).
Definition: gnunet-arm.c:34
static struct Experiment * e
static struct LoggingHandle * l
static int res
static struct GNUNET_HashCode session_id
static unsigned int num_peers
static void cleanup(void *cls)
Function scheduled as very last function, cleans up after us.
static struct GNUNET_FS_DirScanner * ds
Handle to the directory scanner (for recursive insertions).
static int result
Global testing status.
#define info
static unsigned int threshold
What should the threshold for then key be?
static struct GNUNET_SECRETSHARING_Ciphertext ciphertext
static struct GNUNET_SERVICE_Handle * service
Handle to our service instance.
static float beta
Percentage of total peer number in the view to send random PULLs to.
static int check_client_decrypt(void *cls, const struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg)
Check that msg is well-formed.
static void keygen_round2_new_element(void *cls, const struct GNUNET_SET_Element *element)
static struct GNUNET_SECRETSHARING_FairEncryption * keygen_reveal_get_enc_preshare(struct KeygenSession *ks, const struct GNUNET_SECRETSHARING_KeygenRevealData *d, unsigned int idx)
static void keygen_session_destroy(struct KeygenSession *ks)
static void restore_fair(const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, const struct GNUNET_SECRETSHARING_FairEncryption *fe, gcry_mpi_t x, gcry_mpi_t xres)
static void horner_eval(gcry_mpi_t z, gcry_mpi_t *coeff, unsigned int num_coeff, gcry_mpi_t x, gcry_mpi_t m)
Evaluate the polynomial with coefficients coeff at x.
static void insert_decrypt_element(struct DecryptSession *ds)
static void keygen_round1_conclude(void *cls)
Called when the first consensus round has concluded.
static void decrypt_conclude(void *cls)
Called when the partial decryption consensus concludes.
static void handle_client_keygen(void *cls, const struct GNUNET_SECRETSHARING_CreateMessage *msg)
Functions with this signature are called whenever a message is received.
static int check_client_keygen(void *cls, const struct GNUNET_SECRETSHARING_CreateMessage *msg)
Check that msg is well-formed.
static void insert_round2_element(struct KeygenSession *ks)
Insert round 2 element in the consensus, consisting of (1) The exponentiated pre-share polynomial coe...
static struct GNUNET_CRYPTO_EddsaPrivateKey * my_peer_private_key
Peer that runs this service.
static struct KeygenPeerInfo * get_keygen_peer_info(const struct KeygenSession *ks, const struct GNUNET_PeerIdentity *peer)
Get the peer info belonging to a peer identity in a keygen session.
static gcry_mpi_t elgamal_q
The ElGamal prime field order as libgcrypt mpi.
GNUNET_SERVICE_MAIN("secretsharing", GNUNET_SERVICE_OPTION_NONE, &run, &client_connect_cb, &client_disconnect_cb, NULL, GNUNET_MQ_hd_var_size(client_keygen, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_GENERATE, struct GNUNET_SECRETSHARING_CreateMessage, NULL), GNUNET_MQ_hd_var_size(client_decrypt, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT, struct GNUNET_SECRETSHARING_DecryptRequestMessage, NULL), GNUNET_MQ_handler_end())
Define "main" method using service macro.
static void handle_client_decrypt(void *cls, const struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg)
Functions with this signature are called whenever a message is received.
static void keygen_info_destroy(struct KeygenPeerInfo *info)
static const struct GNUNET_CONFIGURATION_Handle * cfg
Configuration of this service.
static int peer_id_cmp(const void *p1, const void *p2)
Compare two peer identities.
static void * client_connect_cb(void *cls, struct GNUNET_SERVICE_Client *c, struct GNUNET_MQ_Handle *mq)
Callback called when a client connects to the service.
static struct GNUNET_TIME_Absolute time_between(struct GNUNET_TIME_Absolute start, struct GNUNET_TIME_Absolute end, int num, int denum)
Interpolate between two points in time.
static void cleanup_task(void *cls)
Task run during shutdown.
static char * mpi_to_str(gcry_mpi_t mpi)
Get a string representation of an MPI.
static int peer_find(const struct GNUNET_PeerIdentity *haystack, unsigned int n, const struct GNUNET_PeerIdentity *needle)
Get the index of a peer in an array of peers.
static struct DecryptPeerInfo * get_decrypt_peer_info(const struct DecryptSession *ds, const struct GNUNET_PeerIdentity *peer)
Get the peer info belonging to a peer identity in a decrypt session.
static void generate_presecret_polynomial(struct KeygenSession *ks)
Generate the random coefficients of our pre-secret polynomial.
static gcry_mpi_t keygen_reveal_get_exp_coeff(struct KeygenSession *ks, const struct GNUNET_SECRETSHARING_KeygenRevealData *d, unsigned int idx)
static struct GNUNET_PeerIdentity * normalize_peers(struct GNUNET_PeerIdentity *listed, unsigned int num_listed, unsigned int *num_normalized, unsigned int *my_peer_idx)
Normalize the given list of peers, by including the local peer (if it is missing) and sorting the pee...
static void decrypt_new_element(void *cls, const struct GNUNET_SET_Element *element)
Called when a new partial decryption arrives.
static void run(void *cls, const struct GNUNET_CONFIGURATION_Handle *c, struct GNUNET_SERVICE_Handle *service)
Initialize secretsharing service.
static gcry_mpi_t elgamal_g
Generator for prime field of order 'elgamal_q'.
static gcry_mpi_t elgamal_p
Modulus of the prime field used for ElGamal.
static void insert_round1_element(struct KeygenSession *ks)
Insert the ephemeral key and the presecret commitment of this peer in the consensus of the given sess...
static gcry_mpi_t keygen_reveal_get_exp_preshare(struct KeygenSession *ks, const struct GNUNET_SECRETSHARING_KeygenRevealData *d, unsigned int idx)
static void compute_lagrange_coefficient(gcry_mpi_t coeff, unsigned int j, unsigned int *indices, unsigned int num)
Get a the j-th lagrange coefficient for a set of indices.
static void decrypt_session_destroy(struct DecryptSession *ds)
Destroy a decrypt session, removing it from the linked list of decrypt sessions.
static void client_disconnect_cb(void *cls, struct GNUNET_SERVICE_Client *c, void *internal_cls)
Callback called when a client disconnected from the service.
static void init_crypto_constants(void)
static void keygen_round1_new_element(void *cls, const struct GNUNET_SET_Element *element)
Consensus element handler for round one.
static void encrypt_fair(gcry_mpi_t v, const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, struct GNUNET_SECRETSHARING_FairEncryption *fe)
Create a fair Paillier encryption of then given ciphertext.
static void keygen_round2_conclude(void *cls)
static struct GNUNET_PeerIdentity my_peer
Peer that runs this service.
static int verify_fair(const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, const struct GNUNET_SECRETSHARING_FairEncryption *fe)
static void get_fair_encryption_challenge(const struct GNUNET_SECRETSHARING_FairEncryption *fe, gcry_mpi_t *e)
static char buf[2048]
static unsigned int element_size
static struct GNUNET_SCHEDULER_Task * t
Main task.
Multi-peer set reconciliation.
Functions related to time.
void GNUNET_CONSENSUS_destroy(struct GNUNET_CONSENSUS_Handle *consensus)
Destroy a consensus handle (free all state associated with it, no longer call any of the callbacks).
void GNUNET_CONSENSUS_insert(struct GNUNET_CONSENSUS_Handle *consensus, const struct GNUNET_SET_Element *element, GNUNET_CONSENSUS_InsertDoneCallback idc, void *idc_cls)
Insert an element in the set being reconsiled.
struct GNUNET_CONSENSUS_Handle * GNUNET_CONSENSUS_create(const struct GNUNET_CONFIGURATION_Handle *cfg, unsigned int num_peers, const struct GNUNET_PeerIdentity *peers, const struct GNUNET_HashCode *session_id, struct GNUNET_TIME_Absolute start, struct GNUNET_TIME_Absolute deadline, GNUNET_CONSENSUS_ElementCallback new_element_cb, void *new_element_cls)
Create a consensus session.
void GNUNET_CONSENSUS_conclude(struct GNUNET_CONSENSUS_Handle *consensus, GNUNET_CONSENSUS_ConcludeCallback conclude, void *conclude_cls)
We are done with inserting new elements into the consensus; try to conclude the consensus within a gi...
struct GNUNET_CRYPTO_EddsaPrivateKey * GNUNET_CRYPTO_eddsa_key_create_from_configuration(const struct GNUNET_CONFIGURATION_Handle *cfg)
Create a new private key by reading our peer's key from the file specified in the configuration.
enum GNUNET_GenericReturnValue GNUNET_CRYPTO_eddsa_sign_(const struct GNUNET_CRYPTO_EddsaPrivateKey *priv, const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose, struct GNUNET_CRYPTO_EddsaSignature *sig)
EdDSA sign a given block.
Definition: crypto_ecc.c:619
enum GNUNET_GenericReturnValue GNUNET_CRYPTO_eddsa_verify_(uint32_t purpose, const struct GNUNET_CRYPTO_EccSignaturePurpose *validate, const struct GNUNET_CRYPTO_EddsaSignature *sig, const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
Verify EdDSA signature.
Definition: crypto_ecc.c:702
enum GNUNET_GenericReturnValue GNUNET_CRYPTO_get_peer_identity(const struct GNUNET_CONFIGURATION_Handle *cfg, struct GNUNET_PeerIdentity *dst)
Retrieve the identity of the host's peer.
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:41
void GNUNET_CRYPTO_mpi_scan_unsigned(gcry_mpi_t *result, const void *data, size_t size)
Convert data buffer into MPI value.
Definition: crypto_mpi.c:132
#define GNUNET_log(kind,...)
#define GNUNET_CRYPTO_PAILLIER_BITS
Size of paillier plain texts and public keys.
void GNUNET_CRYPTO_mpi_print_unsigned(void *buf, size_t size, gcry_mpi_t val)
Output the given MPI value to the given buffer in network byte order.
Definition: crypto_mpi.c:79
void GNUNET_CRYPTO_paillier_create(struct GNUNET_CRYPTO_PaillierPublicKey *public_key, struct GNUNET_CRYPTO_PaillierPrivateKey *private_key)
Create a freshly generated paillier public key.
#define GNUNET_memcmp(a, b)
Compare memory in a and b, where both must be of the same pointer type.
#define GNUNET_memcpy(dst, src, n)
Call memcpy() but check for n being 0 first.
void GNUNET_CRYPTO_paillier_decrypt(const struct GNUNET_CRYPTO_PaillierPrivateKey *private_key, const struct GNUNET_CRYPTO_PaillierPublicKey *public_key, const struct GNUNET_CRYPTO_PaillierCiphertext *ciphertext, gcry_mpi_t m)
Decrypt a paillier ciphertext with a private key.
@ GNUNET_OK
@ GNUNET_YES
@ GNUNET_NO
@ GNUNET_SYSERR
const char * GNUNET_i2s(const struct GNUNET_PeerIdentity *pid)
Convert a peer identity to a string (for printing debug messages).
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur.
@ GNUNET_ERROR_TYPE_WARNING
@ GNUNET_ERROR_TYPE_ERROR
@ GNUNET_ERROR_TYPE_DEBUG
@ GNUNET_ERROR_TYPE_INFO
#define GNUNET_new(type)
Allocate a struct or union of the given type.
#define GNUNET_malloc(size)
Wrapper around malloc.
#define GNUNET_new_array(n, type)
Allocate a size n array with structs or unions of the given type.
#define GNUNET_free(ptr)
Wrapper around free.
void GNUNET_MQ_send(struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev)
Send a message with the given message queue.
Definition: mq.c:304
#define GNUNET_MQ_handler_end()
End-marker for the handlers array.
#define GNUNET_MQ_msg_extra(mvar, esize, type)
Allocate an envelope, with extra space allocated after the space needed by the message struct.
Definition: gnunet_mq_lib.h:62
#define GNUNET_MQ_msg(mvar, type)
Allocate a GNUNET_MQ_Envelope.
Definition: gnunet_mq_lib.h:77
#define GNUNET_MQ_hd_var_size(name, code, str, ctx)
#define GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_SECRET_READY
The cryptosystem has been established.
#define GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT
Request the decryption of a ciphertext.
#define GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT_DONE
The service succeeded in decrypting a ciphertext.
#define GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_GENERATE
Establish a new session.
void GNUNET_SCHEDULER_shutdown(void)
Request the shutdown of a scheduler.
Definition: scheduler.c:534
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_shutdown(GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run on shutdown, that is when a CTRL-C signal is received,...
Definition: scheduler.c:1303
#define GNUNET_SECRETSHARING_ELGAMAL_BITS
Number of bits for secretsharing elements.
void GNUNET_SECRETSHARING_share_destroy(struct GNUNET_SECRETSHARING_Share *share)
#define GNUNET_SECRETSHARING_ELGAMAL_P_HEX
The q-parameter for ElGamal encryption, a 1024-bit safe prime.
#define GNUNET_SECRETSHARING_ELGAMAL_Q_HEX
The q-parameter for ElGamal encryption, a 1023-bit Sophie Germain prime, q = (p-1)/2.
struct GNUNET_SECRETSHARING_Share * GNUNET_SECRETSHARING_share_read(const void *data, size_t len, size_t *readlen)
Read a share from its binary representation.
#define GNUNET_SECRETSHARING_ELGAMAL_G_HEX
The g-parameter for ElGamal encryption, a generator of the unique size q subgroup of Z_p^*.
int GNUNET_SECRETSHARING_share_write(const struct GNUNET_SECRETSHARING_Share *share, void *buf, size_t buflen, size_t *writelen)
Convert a share to its binary representation.
void GNUNET_SERVICE_client_drop(struct GNUNET_SERVICE_Client *c)
Ask the server to disconnect from the given client.
Definition: service.c:2330
void GNUNET_SERVICE_client_continue(struct GNUNET_SERVICE_Client *c)
Continue receiving further messages from the given client.
Definition: service.c:2249
@ GNUNET_SERVICE_OPTION_NONE
Use defaults.
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh(struct GNUNET_TIME_AbsoluteNBO a)
Convert absolute time from network byte order.
Definition: time.c:737
messages used for the secretsharing api
p2p message definitions for secretsharing
State we keep per client.
struct GNUNET_MQ_Handle * mq
MQ to talk to client.
struct KeygenSession * keygen_session
Keygen session of the client, if any.
struct GNUNET_SERVICE_Client * client
Client this is about.
struct DecryptSession * decrypt_session
Decrypt session of the client, if any.
Information about a peer in a decrypt session.
unsigned int original_index
Original index in the key generation round.
struct GNUNET_PeerIdentity peer
Identity of the peer.
gcry_mpi_t partial_decryption
Set to the partial decryption of this peer, or NULL if we did not receive a partial decryption from t...
Session to cooperatively decrypt a value.
struct GNUNET_TIME_Absolute start
When should we start communicating for decryption?
struct DecryptPeerInfo * info
State information about other peers.
struct GNUNET_SECRETSHARING_Share * share
Share of the local peer.
struct ClientState * cs
Which client is this for?
struct GNUNET_TIME_Absolute deadline
When would we like the ciphertext to be decrypted?
struct GNUNET_CONSENSUS_Handle * consensus
Handle to the consensus over partial decryptions.
struct GNUNET_SECRETSHARING_Ciphertext ciphertext
Ciphertext we want to decrypt.
Handle for the service.
Definition: consensus_api.c:40
uint32_t size
How many bytes does this signature sign? (including this purpose header); in network byte order (!...
uint32_t purpose
What does this signature vouch for? This must contain a GNUNET_SIGNATURE_PURPOSE_XXX constant (from g...
Private ECC key encoded for transmission.
unsigned char bits[2048 *2/8]
The bits of the ciphertext.
A 512-bit hashcode.
Handle to a message queue.
Definition: mq.c:87
uint16_t size
The length of the struct (in bytes, including the length field itself), in big-endian format.
The identity of the host (wraps the signing key of the peer).
struct GNUNET_CRYPTO_EddsaPublicKey public_key
uint32_t c1_bits[1024/8/sizeof(uint32_t)]
Data of then element put in consensus for decrypting a value.
struct GNUNET_CRYPTO_EddsaSignature signature
struct GNUNET_SECRETSHARING_FieldElement nizk_commit1
Commitment for the non-interactive zero knowledge proof.
struct GNUNET_CRYPTO_EccSignaturePurpose purpose
struct GNUNET_SECRETSHARING_FieldElement partial_decryption
Partial decryption, computed as .
struct GNUNET_PeerIdentity peer
Peer that inserts this element.
struct GNUNET_SECRETSHARING_Ciphertext ciphertext
Ciphertext we want to decrypt.
struct GNUNET_SECRETSHARING_FieldElement nizk_commit2
Commitment for the non-interactive zero knowledge proof.
struct GNUNET_SECRETSHARING_FieldElement nizk_response
Response to the challenge computed from the protocol transcript.
char t1[GNUNET_SECRETSHARING_ELGAMAL_BITS/8]
char z[GNUNET_SECRETSHARING_ELGAMAL_BITS/8]
char w[GNUNET_CRYPTO_PAILLIER_BITS/8]
struct GNUNET_CRYPTO_PaillierCiphertext c
char h[GNUNET_SECRETSHARING_ELGAMAL_BITS/8]
h = g^x, where x is the fairly encrypted secret.
char t2[GNUNET_CRYPTO_PAILLIER_BITS *2/8]
Consensus element data used in the first round of key generation.
struct GNUNET_PeerIdentity peer
Peer that inserts this element.
struct GNUNET_HashCode commitment
Commitment of 'peer' to its presecret.
struct GNUNET_CRYPTO_PaillierPublicKey pubkey
Ephemeral paillier public key used by 'peer' for this session.
struct GNUNET_CRYPTO_EddsaSignature signature
Signature over the rest of the message.
struct GNUNET_CRYPTO_EccSignaturePurpose purpose
Signature purpose for signing the keygen commit data.
struct GNUNET_CRYPTO_EccSignaturePurpose purpose
struct GNUNET_CRYPTO_EddsaSignature signature
Signature over rest of the message.
struct GNUNET_PeerIdentity peer
Peer that inserts this element.
Notify the client that then threshold secret has been established.
A share, with all values in in host byte order.
uint16_t num_peers
Peers that have the share.
struct GNUNET_SECRETSHARING_FieldElement my_share
Share of 'my_peer'.
struct GNUNET_SECRETSHARING_PublicKey public_key
Public key.
struct GNUNET_PeerIdentity * peers
Peer identities (includes 'my_peer')
uint16_t my_peer
Index of our peer in the list.
struct GNUNET_SECRETSHARING_FieldElement * sigmas
Handle to a client that is connected to a service.
Definition: service.c:252
Handle to a service.
Definition: service.c:118
Element stored in a set.
uint16_t size
Number of bytes in the buffer pointed to by data.
const void * data
Actual data of the element.
uint16_t element_type
Application-specific element type.
Time for absolute times used by GNUnet, in microseconds.
Info about a peer in a key generation session.
int round1_valid
Did we successfully receive the round1 element of the peer?
int round2_valid
Did we successfully receive the round2 element of the peer?
struct GNUNET_CRYPTO_PaillierPublicKey paillier_public_key
The peer's paillier public key.
gcry_mpi_t sigma
Sigma (exponentiated share) for this peer.
gcry_mpi_t preshare_commitment
Commitment to the preshare that is intended for our peer.
gcry_mpi_t presecret_commitment
The peer's commitment to its presecret.
struct GNUNET_PeerIdentity peer
Peer identity of the peer.
Session to establish a threshold-shared secret.
struct GNUNET_TIME_Absolute deadline
When would we like the key to be established?
struct ClientState * cs
Which client is this for?
gcry_mpi_t my_share
Share of our peer.
gcry_mpi_t public_key
Public key, will be updated when a round2 element arrives.
unsigned int local_peer
Index of the local peer.
struct GNUNET_TIME_Absolute start_time
When does the DKG start? Necessary to compute fractions of the operation's desired time interval.
struct GNUNET_CONSENSUS_Handle * consensus
Current consensus, used for both DKG rounds.
gcry_mpi_t * presecret_polynomial
Randomly generated coefficients of the polynomial for sharing our pre-secret, where 'preshares[0]' is...
struct GNUNET_PeerIdentity * peers
List of all peers involved in the secret sharing session.
struct GNUNET_CRYPTO_PaillierPrivateKey paillier_private_key
Paillier private key of our peer.
unsigned int num_peers
Total number of peers.
struct KeygenPeerInfo * info
Information about all participating peers.
unsigned int local_peer_idx
Index of the local peer in the ordered list of peers in the session.
unsigned int threshold
Minimum number of shares required to restore the secret.
struct GNUNET_HashCode session_id
Identifier for this session.
struct GNUNET_TESTBED_Peer * peer
The peer associated with this model.