/*
This file is part of GNUnet.
- (C) 2013 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2013 GNUnet e.V.
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
+ GNUnet is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Affero General Public License as published
+ by the Free Software Foundation, either version 3 of the License,
+ or (at your option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ Affero General Public License for more details.
*/
/**
#include <gcrypt.h>
+#define EXTRA_CHECKS 1
+
+
/**
* Info about a peer in a key generation session.
*/
struct GNUNET_PeerIdentity peer;
/**
- * g-component of the peer's paillier public key.
- */
- gcry_mpi_t paillier_g;
-
- /**
- * mu-component of the peer's paillier public key.
+ * The peer's paillier public key.
+ * Freshly generated for each keygen session.
*/
- gcry_mpi_t paillier_n;
+ struct GNUNET_CRYPTO_PaillierPublicKey paillier_public_key;
/**
* The peer's commitment to his presecret.
gcry_mpi_t presecret_commitment;
/**
- * The peer's preshare that we could decrypt
- * with out private key.
+ * Commitment to the preshare that is
+ * intended for our peer.
*/
- gcry_mpi_t decrypted_preshare;
+ gcry_mpi_t preshare_commitment;
/**
- * Multiplicative share of the public key.
+ * Sigma (exponentiated share) for this peer.
*/
- gcry_mpi_t public_key_share;
+ gcry_mpi_t sigma;
/**
* Did we successfully receive the round1 element
int round1_valid;
/**
- * Did we successfully receive the round1 element
+ * Did we successfully receive the round2 element
* of the peer?
*/
int round2_valid;
};
+/**
+ * Information about a peer in a decrypt session.
+ */
struct DecryptPeerInfo
{
/**
* Original index in the key generation round.
* Necessary for computing the lagrange coefficients.
*/
- unsigned int real_index;
+ unsigned int original_index;
/**
* Set to the partial decryption of
};
+/**
+ * State we keep per client.
+ */
+struct ClientState;
+
+
/**
* Session to establish a threshold-shared secret.
*/
struct KeygenSession
{
- /**
- * Keygen sessions are held in a linked list.
- */
- struct KeygenSession *next;
-
- /**
- * Keygen sessions are held in a linked list.
- */
- struct KeygenSession *prev;
/**
* Current consensus, used for both DKG rounds.
struct GNUNET_CONSENSUS_Handle *consensus;
/**
- * Client that is interested in the result
- * of this key generation session.
- */
- struct GNUNET_SERVER_Client *client;
-
- /**
- * Message queue for 'client'
+ * Which client is this for?
*/
- struct GNUNET_MQ_Handle *client_mq;
+ struct ClientState *cs;
/**
* Randomly generated coefficients of the polynomial for sharing our
struct GNUNET_HashCode session_id;
/**
- * g-component of our peer's paillier private key.
+ * Paillier private key of our peer.
*/
- gcry_mpi_t paillier_lambda;
-
- /**
- * g-component of our peer's paillier private key.
- */
- gcry_mpi_t paillier_mu;
+ struct GNUNET_CRYPTO_PaillierPrivateKey paillier_private_key;
/**
* When would we like the key to be established?
* of peers in the session.
*/
unsigned int local_peer_idx;
-};
-
-struct DecryptSession
-{
/**
- * Decrypt sessions are stored in a linked list.
+ * Share of our peer. Once preshares from other peers are received, they
+ * will be added to 'my'share.
*/
- struct DecryptSession *next;
+ gcry_mpi_t my_share;
/**
- * Decrypt sessions are stored in a linked list.
+ * Public key, will be updated when a round2 element arrives.
*/
- struct DecryptSession *prev;
+ gcry_mpi_t public_key;
+};
+
+
+/**
+ * Session to cooperatively decrypt a value.
+ */
+struct DecryptSession
+{
/**
* Handle to the consensus over partial decryptions.
struct GNUNET_CONSENSUS_Handle *consensus;
/**
- * Client connected to us.
+ * Which client is this for?
*/
- struct GNUNET_SERVER_Client *client;
+ struct ClientState *cs;
/**
- * Message queue for 'client'.
+ * When should we start communicating for decryption?
*/
- struct GNUNET_MQ_Handle *client_mq;
+ struct GNUNET_TIME_Absolute start;
/**
* When would we like the ciphertext to be
/**
* Share of the local peer.
+ * Containts other important information, such as
+ * the list of other peers.
*/
struct GNUNET_SECRETSHARING_Share *share;
/**
- * Decrypt sessions are held in a linked list.
+ * State we keep per client.
*/
-static struct DecryptSession *decrypt_sessions_head;
+struct ClientState
+{
+ /**
+ * Decrypt session of the client, if any.
+ */
+ struct DecryptSession *decrypt_session;
-/**
- * Decrypt sessions are held in a linked list.
- */
-static struct DecryptSession *decrypt_sessions_tail;
+ /**
+ * Keygen session of the client, if any.
+ */
+ struct KeygenSession *keygen_session;
-/**
- * Decrypt sessions are held in a linked list.
- */
-static struct KeygenSession *keygen_sessions_head;
+ /**
+ * Client this is about.
+ */
+ struct GNUNET_SERVICE_Client *client;
+
+ /**
+ * MQ to talk to @a client.
+ */
+ struct GNUNET_MQ_Handle *mq;
+
+};
-/**
- * Decrypt sessions are held in a linked list.
- */
-static struct KeygenSession *keygen_sessions_tail;
/**
* The ElGamal prime field order as libgcrypt mpi.
- * Will be initialized to 'ELGAMAL_Q_DATA'.
+ * Initialized in #init_crypto_constants.
*/
static gcry_mpi_t elgamal_q;
/**
* Modulus of the prime field used for ElGamal.
- * Will be initialized to 'ELGAMAL_P_DATA'.
+ * Initialized in #init_crypto_constants.
*/
static gcry_mpi_t elgamal_p;
/**
* Generator for prime field of order 'elgamal_q'.
- * Will be initialized to 'ELGAMAL_G_DATA'.
+ * Initialized in #init_crypto_constants.
*/
static gcry_mpi_t elgamal_g;
*/
static const struct GNUNET_CONFIGURATION_Handle *cfg;
-/**
- * Server for this service.
- */
-static struct GNUNET_SERVER_Handle *srv;
/**
- * Print a field element in a fixed-size buffer.
+ * Get the peer info belonging to a peer identity in a keygen session.
+ *
+ * @param ks The keygen session.
+ * @param peer The peer identity.
+ * @return The Keygen peer info, or NULL if the peer could not be found.
*/
-static void
-print_field_element (void *buf, gcry_mpi_t x)
-{
- GNUNET_assert (0);
-}
-
-
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 decrypt session.
+ *
+ * @param ds The decrypt session.
+ * @param peer The peer identity.
+ * @return The decrypt peer info, or NULL if the peer could not be found.
+ */
static struct DecryptPeerInfo *
get_decrypt_peer_info (const struct DecryptSession *ds,
- const struct GNUNET_PeerIdentity *peer)
+ const struct GNUNET_PeerIdentity *peer)
{
unsigned int i;
for (i = 0; i < ds->share->num_peers; i++)
}
+/**
+ * Interpolate between two points in time.
+ *
+ * @param start start time
+ * @param end end time
+ * @param num numerator of the scale factor
+ * @param denum denumerator of the scale factor
+ */
static struct GNUNET_TIME_Absolute
time_between (struct GNUNET_TIME_Absolute start,
struct GNUNET_TIME_Absolute end,
/**
* Compare two peer identities. Indended to be used with qsort or bsearch.
*
- * @param p1 some peer identity
- * @param p2 some peer identity
+ * @param p1 Some peer identity.
+ * @param p2 Some peer identity.
* @return 1 if p1 > p2, -1 if p1 < p2 and 0 if p1 == p2.
*/
static int
peer_id_cmp (const void *p1, const void *p2)
{
- return memcmp (p1, p2, sizeof (struct GNUNET_PeerIdentity));
+ return memcmp (p1,
+ p2,
+ sizeof (struct GNUNET_PeerIdentity));
}
-int
+/**
+ * Get the index of a peer in an array of peers
+ *
+ * @param haystack Array of peers.
+ * @param n Size of @a haystack.
+ * @param needle Peer to find
+ * @return Index of @a needle in @a haystack, or -1 if peer
+ * is not in the list.
+ */
+static int
peer_find (const struct GNUNET_PeerIdentity *haystack, unsigned int n,
const struct GNUNET_PeerIdentity *needle)
{
unsigned int i;
+
for (i = 0; i < n; i++)
- if (0 == memcmp (&haystack[i], needle, sizeof (struct GNUNET_PeerIdentity)))
+ if (0 == memcmp (&haystack[i],
+ needle,
+ sizeof (struct GNUNET_PeerIdentity)))
return i;
return -1;
}
* Normalize the given list of peers, by including the local peer
* (if it is missing) and sorting the peers by their identity.
*
- * @param listed peers in the unnormalized list
- * @param num_listed peers in the un-normalized list
- * @param[out] num_normalized number of peers in the normalized list
- * @param[out] my_peer_idx index of the local peer in the normalized list
- * @return normalized list, must be free'd by the caller
+ * @param listed Peers in the unnormalized list.
+ * @param num_listed Peers in the un-normalized list.
+ * @param[out] num_normalized Number of peers in the normalized list.
+ * @param[out] my_peer_idx Index of the local peer in the normalized list.
+ * @return Normalized list, must be free'd by the caller.
*/
static struct GNUNET_PeerIdentity *
normalize_peers (struct GNUNET_PeerIdentity *listed,
unsigned int *my_peer_idx)
{
unsigned int local_peer_in_list;
+ /* number of peers in the normalized list */
unsigned int n;
struct GNUNET_PeerIdentity *normalized;
n += 1;
}
- normalized = GNUNET_new_array (n, struct GNUNET_PeerIdentity);
+ normalized = GNUNET_new_array (n,
+ struct GNUNET_PeerIdentity);
if (GNUNET_NO == local_peer_in_list)
normalized[n - 1] = my_peer;
- memcpy (normalized, listed, num_listed * sizeof (struct GNUNET_PeerIdentity));
- qsort (normalized, n, sizeof (struct GNUNET_PeerIdentity), &peer_id_cmp);
+ GNUNET_memcpy (normalized,
+ listed,
+ num_listed * sizeof (struct GNUNET_PeerIdentity));
+ qsort (normalized,
+ n,
+ sizeof (struct GNUNET_PeerIdentity),
+ &peer_id_cmp);
if (NULL != my_peer_idx)
*my_peer_idx = peer_find (normalized, n, &my_peer);
/**
- * Get a the j-th lagrage coefficient for a set of indices.
+ * Get a the j-th lagrange coefficient for a set of indices.
*
* @param[out] coeff the lagrange coefficient
- * @param j lagrage coefficient we want to compute
+ * @param j lagrange coefficient we want to compute
* @param indices indices
* @param num number of indices in @a indices
*/
unsigned int *indices,
unsigned int num)
{
- int i;
+ unsigned int i;
/* numerator */
gcry_mpi_t n;
/* denominator */
gcry_mpi_set_ui (n, 1);
gcry_mpi_set_ui (d, 1);
- gcry_mpi_set_ui (coeff, 0);
for (i = 0; i < num; i++)
{
- int l = indices[i];
+ unsigned int l = indices[i];
if (l == j)
continue;
- gcry_mpi_mul_ui (n, n, l);
+ gcry_mpi_mul_ui (n, n, l + 1);
// d <- d * (l-j)
- gcry_mpi_set_ui (tmp, l);
- gcry_mpi_sub_ui (tmp, tmp, j);
+ gcry_mpi_set_ui (tmp, l + 1);
+ gcry_mpi_sub_ui (tmp, tmp, j + 1);
gcry_mpi_mul (d, d, tmp);
}
+ // gcry_mpi_invm does not like negative numbers ...
+ gcry_mpi_mod (d, d, elgamal_q);
+
+ GNUNET_assert (gcry_mpi_cmp_ui (d, 0) > 0);
+
// now we do the actual division, with everything mod q, as we
- // are not operating on elemets from <g>, but on exponents
- GNUNET_assert (0 == gcry_mpi_invm (d, d, elgamal_q));
+ // are not operating on elements from <g>, but on exponents
+ GNUNET_assert (0 != gcry_mpi_invm (d, d, elgamal_q));
+
gcry_mpi_mulm (coeff, n, d, elgamal_q);
gcry_mpi_release (n);
/**
- * Create a key pair for the paillier crypto system.
+ * Destroy a decrypt session, removing it from
+ * the linked list of decrypt sessions.
*
- * Uses the simplified key generation of Jonathan Katz, Yehuda Lindell,
- * "Introduction to Modern Cryptography: Principles and Protocols".
- *
- * @param g g-component of public key
- * @param n n-component of public key
- * @param lambda lambda-component of private key
- * @param mu mu-componenent of private key
+ * @param ds decrypt session to destroy
*/
static void
-paillier_create (gcry_mpi_t g, gcry_mpi_t n, gcry_mpi_t lambda, gcry_mpi_t mu)
+decrypt_session_destroy (struct DecryptSession *ds)
{
- gcry_mpi_t p;
- gcry_mpi_t q;
- gcry_mpi_t phi;
- gcry_mpi_t tmp;
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "destroying decrypt session\n");
+ if (NULL != ds->cs)
+ {
+ ds->cs->decrypt_session = NULL;
+ ds->cs = NULL;
+ }
+ if (NULL != ds->consensus)
+ {
+ GNUNET_CONSENSUS_destroy (ds->consensus);
+ ds->consensus = NULL;
+ }
- GNUNET_assert (0 != (phi = gcry_mpi_new (PAILLIER_BITS)));
- GNUNET_assert (0 != (tmp = gcry_mpi_new (PAILLIER_BITS)));
-
- // generate rsa modulus
- GNUNET_assert (0 == gcry_prime_generate (&p, PAILLIER_BITS / 2, 0, NULL, NULL, NULL,
- GCRY_WEAK_RANDOM, 0));
- GNUNET_assert (0 == gcry_prime_generate (&q, PAILLIER_BITS / 2, 0, NULL, NULL, NULL,
- GCRY_WEAK_RANDOM, 0));
- gcry_mpi_mul (n, p, q);
- gcry_mpi_add_ui (g, n, 1);
- // compute phi(n) = (p-1)(q-1)
- gcry_mpi_sub_ui (phi, p, 1);
- gcry_mpi_sub_ui (tmp, q, 1);
- gcry_mpi_mul (phi, phi, tmp);
- gcry_mpi_set (lambda, phi);
- // compute mu
- GNUNET_assert (0 != gcry_mpi_invm (mu, phi, n));
-
- gcry_mpi_release (p);
- gcry_mpi_release (q);
- gcry_mpi_release (phi);
- gcry_mpi_release (tmp);
+ if (NULL != ds->info)
+ {
+ for (unsigned int i = 0; i < ds->share->num_peers; i++)
+ {
+ if (NULL != ds->info[i].partial_decryption)
+ {
+ gcry_mpi_release (ds->info[i].partial_decryption);
+ ds->info[i].partial_decryption = NULL;
+ }
+ }
+ GNUNET_free (ds->info);
+ ds->info = NULL;
+ }
+ if (NULL != ds->share)
+ {
+ GNUNET_SECRETSHARING_share_destroy (ds->share);
+ ds->share = NULL;
+ }
+
+ GNUNET_free (ds);
}
-/**
- * Encrypt a value using Paillier's scheme.
- *
- * @param c resulting ciphertext
- * @param m plaintext to encrypt
- * @param g g-component of public key
- * @param n n-component of public key
- */
static void
-paillier_encrypt (gcry_mpi_t c, gcry_mpi_t m, gcry_mpi_t g, gcry_mpi_t n)
+keygen_info_destroy (struct KeygenPeerInfo *info)
{
- gcry_mpi_t n_square;
- gcry_mpi_t r;
-
- GNUNET_assert (0 != (n_square = gcry_mpi_new (0)));
- GNUNET_assert (0 != (r = gcry_mpi_new (0)));
-
- gcry_mpi_mul (n_square, n, n);
-
- // generate r < n
- do
+ if (NULL != info->sigma)
{
- gcry_mpi_randomize (r, PAILLIER_BITS, GCRY_WEAK_RANDOM);
+ gcry_mpi_release (info->sigma);
+ info->sigma = NULL;
+ }
+ if (NULL != info->presecret_commitment)
+ {
+ gcry_mpi_release (info->presecret_commitment);
+ info->presecret_commitment = NULL;
+ }
+ if (NULL != info->preshare_commitment)
+ {
+ gcry_mpi_release (info->preshare_commitment);
+ info->preshare_commitment = NULL;
}
- while (gcry_mpi_cmp (r, n) > 0);
-
- gcry_mpi_powm (c, g, m, n_square);
- gcry_mpi_powm (r, r, n, n_square);
- gcry_mpi_mulm (c, r, c, n_square);
-
- gcry_mpi_release (n_square);
- gcry_mpi_release (r);
}
-/**
- * Decrypt a ciphertext using Paillier's scheme.
- *
- * @param[out] m resulting plaintext
- * @param c ciphertext to decrypt
- * @param lambda lambda-component of private key
- * @param mu mu-component of private key
- * @param n n-component of public key
- */
static void
-paillier_decrypt (gcry_mpi_t m, gcry_mpi_t c, gcry_mpi_t mu, gcry_mpi_t lambda, gcry_mpi_t n)
+keygen_session_destroy (struct KeygenSession *ks)
{
- gcry_mpi_t n_square;
- GNUNET_assert (0 != (n_square = gcry_mpi_new (0)));
- gcry_mpi_mul (n_square, n, n);
- gcry_mpi_powm (m, c, lambda, n_square);
- gcry_mpi_sub_ui (m, m, 1);
- // m = m/n
- gcry_mpi_div (m, NULL, m, n, 0);
- gcry_mpi_mulm (m, m, mu, n);
- gcry_mpi_release (n_square);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "destroying keygen session\n");
+
+ if (NULL != ks->cs)
+ {
+ ks->cs->keygen_session = NULL;
+ ks->cs = NULL;
+ }
+ if (NULL != ks->info)
+ {
+ for (unsigned int i = 0; i < ks->num_peers; i++)
+ keygen_info_destroy (&ks->info[i]);
+ GNUNET_free (ks->info);
+ ks->info = NULL;
+ }
+
+ if (NULL != ks->consensus)
+ {
+ GNUNET_CONSENSUS_destroy (ks->consensus);
+ ks->consensus = NULL;
+ }
+
+ if (NULL != ks->presecret_polynomial)
+ {
+ for (unsigned int i = 0; i < ks->threshold; i++)
+ {
+ GNUNET_assert (NULL != ks->presecret_polynomial[i]);
+ gcry_mpi_release (ks->presecret_polynomial[i]);
+ ks->presecret_polynomial[i] = NULL;
+ }
+ GNUNET_free (ks->presecret_polynomial);
+ ks->presecret_polynomial = NULL;
+ }
+ if (NULL != ks->my_share)
+ {
+ gcry_mpi_release (ks->my_share);
+ ks->my_share = NULL;
+ }
+ if (NULL != ks->public_key)
+ {
+ gcry_mpi_release (ks->public_key);
+ ks->public_key = NULL;
+ }
+ if (NULL != ks->peers)
+ {
+ GNUNET_free (ks->peers);
+ ks->peers = NULL;
+ }
+ GNUNET_free (ks);
}
* @param tc unused
*/
static void
-cleanup_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+cleanup_task (void *cls)
{
- /* FIXME: do clean up here */
+ /* Nothing to do! */
}
+
+/**
+ * Generate the random coefficients of our pre-secret polynomial
+ *
+ * @param ks the session
+ */
static void
generate_presecret_polynomial (struct KeygenSession *ks)
{
int i;
+ gcry_mpi_t v;
+
GNUNET_assert (NULL == ks->presecret_polynomial);
- ks->presecret_polynomial = GNUNET_malloc (ks->threshold * sizeof (gcry_mpi_t));
+ ks->presecret_polynomial = GNUNET_new_array (ks->threshold,
+ gcry_mpi_t);
for (i = 0; i < ks->threshold; i++)
{
- ks->presecret_polynomial[i] = gcry_mpi_new (PAILLIER_BITS);
- GNUNET_assert (0 != ks->presecret_polynomial[i]);
- gcry_mpi_randomize (ks->presecret_polynomial[i], PAILLIER_BITS,
- GCRY_WEAK_RANDOM);
+ v = ks->presecret_polynomial[i] = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS);
+ GNUNET_assert (NULL != v);
+ // Randomize v such that 0 < v < elgamal_q.
+ // The '- 1' is necessary as bitlength(q) = bitlength(p) - 1.
+ do
+ {
+ gcry_mpi_randomize (v, GNUNET_SECRETSHARING_ELGAMAL_BITS - 1, GCRY_WEAK_RANDOM);
+ } while ((gcry_mpi_cmp_ui (v, 0) == 0) || (gcry_mpi_cmp (v, elgamal_q) >= 0));
}
}
/**
* Consensus element handler for round one.
+ * We should get one ephemeral key for each peer.
*
- * @param cls closure (keygen session)
- * @param element the element from consensus
+ * @param cls Closure (keygen session).
+ * @param element The element from consensus, or
+ * NULL if consensus failed.
*/
static void
keygen_round1_new_element (void *cls,
return;
}
+ /* elements have fixed size */
if (element->size != sizeof (struct GNUNET_SECRETSHARING_KeygenCommitData))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "keygen commit data with wrong size (%u) in consensus, "
- " %u expected\n",
- element->size, sizeof (struct GNUNET_SECRETSHARING_KeygenCommitData));
+ "keygen commit data with wrong size (%u) in consensus, %u expected\n",
+ (unsigned int) element->size,
+ (unsigned int) sizeof (struct GNUNET_SECRETSHARING_KeygenCommitData));
return;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO, "got round1 element\n");
d = element->data;
-
info = get_keygen_peer_info (ks, &d->peer);
if (NULL == info)
return;
}
+ /* Check that the right amount of data has been signed. */
if (d->purpose.size !=
htonl (element->size - offsetof (struct GNUNET_SECRETSHARING_KeygenCommitData, purpose)))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen commit data with invalid signature in consensus\n");
return;
}
-
- GNUNET_assert (0 == gcry_mpi_scan (&info->paillier_g, GCRYMPI_FMT_USG,
- &d->pubkey.g, sizeof d->pubkey.g, NULL));
- GNUNET_assert (0 == gcry_mpi_scan (&info->paillier_n, GCRYMPI_FMT_USG,
- &d->pubkey.n, sizeof d->pubkey.n, NULL));
- GNUNET_assert (0 == gcry_mpi_scan (&info->presecret_commitment, GCRYMPI_FMT_USG,
- &d->commitment, sizeof d->commitment, NULL));
+ info->paillier_public_key = d->pubkey;
+ GNUNET_CRYPTO_mpi_scan_unsigned (&info->presecret_commitment, &d->commitment, 512 / 8);
info->round1_valid = GNUNET_YES;
}
unsigned int i;
unsigned int j;
struct GNUNET_SECRETSHARING_Share *share;
- gcry_mpi_t s;
- gcry_mpi_t h;
GNUNET_log (GNUNET_ERROR_TYPE_INFO, "round2 conclude\n");
- GNUNET_assert (0 != (s = gcry_mpi_new (PAILLIER_BITS)));
- GNUNET_assert (0 != (h = gcry_mpi_new (PAILLIER_BITS)));
-
- // multiplicative identity
- gcry_mpi_set_ui (s, 1);
+ GNUNET_CONSENSUS_destroy (ks->consensus);
+ ks->consensus = NULL;
share = GNUNET_new (struct GNUNET_SECRETSHARING_Share);
if (GNUNET_YES == ks->info[i].round2_valid)
share->num_peers++;
- share->peers = GNUNET_new_array (share->num_peers, struct GNUNET_PeerIdentity);
- share->hom_share_commitments =
- GNUNET_new_array (share->num_peers, struct GNUNET_SECRETSHARING_FieldElement);
- share->original_indices = GNUNET_new_array (share->num_peers, uint16_t);
+ share->peers = GNUNET_new_array (share->num_peers,
+ struct GNUNET_PeerIdentity);
+ share->sigmas =
+ GNUNET_new_array (share->num_peers,
+ struct GNUNET_SECRETSHARING_FieldElement);
+ share->original_indices = GNUNET_new_array (share->num_peers,
+ uint16_t);
- j = 0;
+ /* maybe we're not even in the list of peers? */
+ share->my_peer = share->num_peers;
+
+ j = 0; /* running index of valid peers */
for (i = 0; i < ks->num_peers; i++)
{
if (GNUNET_YES == ks->info[i].round2_valid)
{
- gcry_mpi_addm (s, s, ks->info[i].decrypted_preshare, elgamal_p);
- gcry_mpi_mulm (h, h, ks->info[i].public_key_share, elgamal_p);
- share->peers[i] = ks->info[i].peer;
- share->original_indices[i] = j++;
+ share->peers[j] = ks->info[i].peer;
+ GNUNET_CRYPTO_mpi_print_unsigned (&share->sigmas[j],
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
+ ks->info[i].sigma);
+ share->original_indices[i] = j;
+ if (0 == memcmp (&share->peers[i], &my_peer, sizeof (struct GNUNET_PeerIdentity)))
+ share->my_peer = j;
+ j += 1;
}
}
- gcry_mpi_print (GCRYMPI_FMT_USG, (void *) &share->my_share, PAILLIER_BITS / 8, NULL, s);
- gcry_mpi_print (GCRYMPI_FMT_USG, (void *) &share->public_key, PAILLIER_BITS / 8, NULL, s);
+ if (share->my_peer == share->num_peers)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO, "P%u: peer identity not in share\n", ks->local_peer_idx);
+ }
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "keygen successful with %u peers\n", share->num_peers);
+ GNUNET_CRYPTO_mpi_print_unsigned (&share->my_share, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
+ ks->my_share);
+ GNUNET_CRYPTO_mpi_print_unsigned (&share->public_key, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
+ ks->public_key);
- m = GNUNET_malloc (sizeof (struct GNUNET_SECRETSHARING_SecretReadyMessage) +
- ks->num_peers * sizeof (struct GNUNET_PeerIdentity));
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO, "keygen completed with %u peers\n", share->num_peers);
+
+ /* Write the share. If 0 peers completed the dkg, an empty
+ * share will be sent. */
GNUNET_assert (GNUNET_OK == GNUNET_SECRETSHARING_share_write (share, NULL, 0, &share_size));
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "writing share of size %u\n",
+ (unsigned int) share_size);
+
ev = GNUNET_MQ_msg_extra (m, share_size,
GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_SECRET_READY);
GNUNET_assert (GNUNET_OK == GNUNET_SECRETSHARING_share_write (share, &m[1], share_size, NULL));
- GNUNET_MQ_send (ks->client_mq, ev);
+ GNUNET_SECRETSHARING_share_destroy (share);
+ share = NULL;
+
+ GNUNET_MQ_send (ks->cs->mq,
+ ev);
+}
+
+
+
+static void
+restore_fair (const struct GNUNET_CRYPTO_PaillierPublicKey *ppub,
+ const struct GNUNET_SECRETSHARING_FairEncryption *fe,
+ gcry_mpi_t x, gcry_mpi_t xres)
+{
+ gcry_mpi_t a_1;
+ gcry_mpi_t a_2;
+ gcry_mpi_t b_1;
+ gcry_mpi_t b_2;
+ gcry_mpi_t big_a;
+ gcry_mpi_t big_b;
+ gcry_mpi_t big_t;
+ gcry_mpi_t n;
+ gcry_mpi_t t_1;
+ gcry_mpi_t t_2;
+ gcry_mpi_t t;
+ gcry_mpi_t r;
+ gcry_mpi_t v;
+
+
+ GNUNET_assert (NULL != (n = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (t = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (t_1 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (t_2 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (big_t = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (v = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (big_a = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (big_b = gcry_mpi_new (0)));
+
+ // a = (N,0)^T
+ GNUNET_CRYPTO_mpi_scan_unsigned (&a_1, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
+ GNUNET_assert (NULL != (a_2 = gcry_mpi_new (0)));
+ gcry_mpi_set_ui (a_2, 0);
+ // b = (x,1)^T
+ GNUNET_assert (NULL != (b_1 = gcry_mpi_new (0)));
+ gcry_mpi_set (b_1, x);
+ GNUNET_assert (NULL != (b_2 = gcry_mpi_new (0)));
+ gcry_mpi_set_ui (b_2, 1);
+
+ // A = a DOT a
+ gcry_mpi_mul (t, a_1, a_1);
+ gcry_mpi_mul (big_a, a_2, a_2);
+ gcry_mpi_add (big_a, big_a, t);
+
+ // B = b DOT b
+ gcry_mpi_mul (t, b_1, b_1);
+ gcry_mpi_mul (big_b, b_2, b_2);
+ gcry_mpi_add (big_b, big_b, t);
+
+ while (1)
+ {
+ // n = a DOT b
+ gcry_mpi_mul (t, a_1, b_1);
+ gcry_mpi_mul (n, a_2, b_2);
+ gcry_mpi_add (n, n, t);
+
+ // r = nearest(n/B)
+ gcry_mpi_div (r, NULL, n, big_b, 0);
+
+ // T := A - 2rn + rrB
+ gcry_mpi_mul (v, r, n);
+ gcry_mpi_mul_ui (v, v, 2);
+ gcry_mpi_sub (big_t, big_a, v);
+ gcry_mpi_mul (v, r, r);
+ gcry_mpi_mul (v, v, big_b);
+ gcry_mpi_add (big_t, big_t, v);
+
+ if (gcry_mpi_cmp (big_t, big_b) >= 0)
+ {
+ break;
+ }
+
+ // t = a - rb
+ gcry_mpi_mul (v, r, b_1);
+ gcry_mpi_sub (t_1, a_1, v);
+ gcry_mpi_mul (v, r, b_2);
+ gcry_mpi_sub (t_2, a_2, v);
+
+ // a = b
+ gcry_mpi_set (a_1, b_1);
+ gcry_mpi_set (a_2, b_2);
+ // b = t
+ gcry_mpi_set (b_1, t_1);
+ gcry_mpi_set (b_2, t_2);
+
+ gcry_mpi_set (big_a, big_b);
+ gcry_mpi_set (big_b, big_t);
+ }
+
+ {
+ gcry_mpi_t paillier_n;
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&paillier_n, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
+
+ gcry_mpi_set (xres, b_2);
+ gcry_mpi_invm (xres, xres, elgamal_q);
+ gcry_mpi_mulm (xres, xres, b_1, elgamal_q);
+ }
+
+ gcry_mpi_release (a_1);
+ gcry_mpi_release (a_2);
+ gcry_mpi_release (b_1);
+ gcry_mpi_release (b_2);
+ gcry_mpi_release (big_a);
+ gcry_mpi_release (big_b);
+ gcry_mpi_release (big_t);
+ gcry_mpi_release (n);
+ gcry_mpi_release (t_1);
+ gcry_mpi_release (t_2);
+ gcry_mpi_release (t);
+ gcry_mpi_release (r);
+ gcry_mpi_release (v);
+}
+
+
+static void
+get_fair_encryption_challenge (const struct GNUNET_SECRETSHARING_FairEncryption *fe, gcry_mpi_t e)
+{
+ struct {
+ struct GNUNET_CRYPTO_PaillierCiphertext c;
+ char h[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
+ char t1[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
+ char t2[GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8];
+ } hash_data;
+ struct GNUNET_HashCode e_hash;
+
+ GNUNET_memcpy (&hash_data.c, &fe->c, sizeof (struct GNUNET_CRYPTO_PaillierCiphertext));
+ GNUNET_memcpy (&hash_data.h, &fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_memcpy (&hash_data.t1, &fe->t1, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_memcpy (&hash_data.t2, &fe->t2, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&e, &e_hash, sizeof (struct GNUNET_HashCode));
+ gcry_mpi_mod (e, e, elgamal_q);
+}
+
+
+static int
+verify_fair (const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, const struct GNUNET_SECRETSHARING_FairEncryption *fe)
+{
+ gcry_mpi_t n;
+ gcry_mpi_t n_sq;
+ gcry_mpi_t z;
+ gcry_mpi_t t1;
+ gcry_mpi_t t2;
+ gcry_mpi_t e;
+ gcry_mpi_t w;
+ gcry_mpi_t tmp1;
+ gcry_mpi_t tmp2;
+ gcry_mpi_t y;
+ gcry_mpi_t big_y;
+ int res;
+
+ GNUNET_assert (NULL != (n_sq = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (tmp1 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (tmp2 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (e = gcry_mpi_new (0)));
+
+ get_fair_encryption_challenge (fe, e);
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&n, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
+ GNUNET_CRYPTO_mpi_scan_unsigned (&t1, fe->t1, GNUNET_CRYPTO_PAILLIER_BITS / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&z, fe->z, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&y, fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&w, fe->w, GNUNET_CRYPTO_PAILLIER_BITS / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&big_y, fe->c.bits, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&t2, fe->t2, GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8);
+ gcry_mpi_mul (n_sq, n, n);
+
+ // tmp1 = g^z
+ gcry_mpi_powm (tmp1, elgamal_g, z, elgamal_p);
+ // tmp2 = y^{-e}
+ gcry_mpi_powm (tmp1, y, e, elgamal_p);
+ gcry_mpi_invm (tmp1, tmp1, elgamal_p);
+ // tmp1 = tmp1 * tmp2
+ gcry_mpi_mulm (tmp1, tmp1, tmp2, elgamal_p);
+
+ if (0 == gcry_mpi_cmp (t1, tmp1))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "fair encryption invalid (t1)\n");
+ res = GNUNET_NO;
+ goto cleanup;
+ }
+
+ gcry_mpi_powm (big_y, big_y, e, n_sq);
+ gcry_mpi_invm (big_y, big_y, n_sq);
+
+ gcry_mpi_add_ui (tmp1, n, 1);
+ gcry_mpi_powm (tmp1, tmp1, z, n_sq);
+
+ gcry_mpi_powm (tmp2, w, n, n_sq);
+
+ gcry_mpi_mulm (tmp1, tmp1, tmp2, n_sq);
+ gcry_mpi_mulm (tmp1, tmp1, big_y, n_sq);
+
+
+ if (0 == gcry_mpi_cmp (t2, tmp1))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "fair encryption invalid (t2)\n");
+ res = GNUNET_NO;
+ goto cleanup;
+ }
+
+ res = GNUNET_YES;
+
+cleanup:
+
+ gcry_mpi_release (n);
+ gcry_mpi_release (n_sq);
+ gcry_mpi_release (z);
+ gcry_mpi_release (t1);
+ gcry_mpi_release (t2);
+ gcry_mpi_release (e);
+ gcry_mpi_release (w);
+ gcry_mpi_release (tmp1);
+ gcry_mpi_release (tmp2);
+ gcry_mpi_release (y);
+ gcry_mpi_release (big_y);
+ return res;
+}
+
+
+/**
+ * Create a fair Paillier encryption of then given ciphertext.
+ *
+ * @param v the ciphertext
+ * @param[out] fe the fair encryption
+ */
+static void
+encrypt_fair (gcry_mpi_t v, const struct GNUNET_CRYPTO_PaillierPublicKey *ppub, struct GNUNET_SECRETSHARING_FairEncryption *fe)
+{
+ gcry_mpi_t r;
+ gcry_mpi_t s;
+ gcry_mpi_t t1;
+ gcry_mpi_t t2;
+ gcry_mpi_t z;
+ gcry_mpi_t w;
+ gcry_mpi_t n;
+ gcry_mpi_t e;
+ gcry_mpi_t n_sq;
+ gcry_mpi_t u;
+ gcry_mpi_t Y;
+ gcry_mpi_t G;
+ gcry_mpi_t h;
+ GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (s = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (t1 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (t2 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (z = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (w = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (n_sq = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (e = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (u = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (Y = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (G = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (h = gcry_mpi_new (0)));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&n, ppub, sizeof (struct GNUNET_CRYPTO_PaillierPublicKey));
+ gcry_mpi_mul (n_sq, n, n);
+ gcry_mpi_add_ui (G, n, 1);
+
+ do {
+ gcry_mpi_randomize (u, GNUNET_CRYPTO_PAILLIER_BITS, GCRY_WEAK_RANDOM);
+ }
+ while (gcry_mpi_cmp (u, n) >= 0);
+
+ gcry_mpi_powm (t1, G, v, n_sq);
+ gcry_mpi_powm (t2, u, n, n_sq);
+ gcry_mpi_mulm (Y, t1, t2, n_sq);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (fe->c.bits,
+ sizeof fe->c.bits,
+ Y);
+
+
+ gcry_mpi_randomize (r, 2048, GCRY_WEAK_RANDOM);
+ do {
+ gcry_mpi_randomize (s, GNUNET_CRYPTO_PAILLIER_BITS, GCRY_WEAK_RANDOM);
+ }
+ while (gcry_mpi_cmp (s, n) >= 0);
+
+ // compute t1
+ gcry_mpi_mulm (t1, elgamal_g, r, elgamal_p);
+ // compute t2 (use z and w as temp)
+ gcry_mpi_powm (z, G, r, n_sq);
+ gcry_mpi_powm (w, s, n, n_sq);
+ gcry_mpi_mulm (t2, z, w, n_sq);
+
+
+ gcry_mpi_powm (h, elgamal_g, v, elgamal_p);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (fe->h,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
+ h);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (fe->t1,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
+ t1);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (fe->t2,
+ GNUNET_CRYPTO_PAILLIER_BITS * 2 / 8,
+ t2);
+
+
+ get_fair_encryption_challenge (fe, e);
+
+ // compute z
+ gcry_mpi_mul (z, e, v);
+ gcry_mpi_addm (z, z, r, elgamal_q);
+ // compute w
+ gcry_mpi_powm (w, u, e, n);
+ gcry_mpi_mulm (w, w, s, n);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (fe->z,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8,
+ z);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (fe->w,
+ GNUNET_CRYPTO_PAILLIER_BITS / 8,
+ w);
+
+ gcry_mpi_release (n);
+ gcry_mpi_release (r);
+ gcry_mpi_release (s);
+ gcry_mpi_release (t1);
+ gcry_mpi_release (t2);
+ gcry_mpi_release (z);
+ gcry_mpi_release (w);
+ gcry_mpi_release (e);
+ gcry_mpi_release (n_sq);
+ gcry_mpi_release (u);
+ gcry_mpi_release (Y);
+ gcry_mpi_release (G);
+ gcry_mpi_release (h);
}
* (1) The exponentiated pre-share polynomial coefficients A_{i,l}=g^{a_{i,l}}
* (2) The exponentiated pre-shares y_{i,j}=g^{s_{i,j}}
* (3) The encrypted pre-shares Y_{i,j}
- * (4) The zero knowledge proof for correctness of
- * the encryption
+ * (4) The zero knowledge proof for fairness of
+ * the encryption
*
* @param ks session to use
*/
gcry_mpi_t idx;
gcry_mpi_t v;
- GNUNET_assert (0 != (v = gcry_mpi_new (PAILLIER_BITS)));
- GNUNET_assert (0 != (idx = gcry_mpi_new (PAILLIER_BITS)));
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting round2 element\n",
+ ks->local_peer_idx);
+
+ GNUNET_assert (NULL != (v = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
+ GNUNET_assert (NULL != (idx = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
element_size = (sizeof (struct GNUNET_SECRETSHARING_KeygenRevealData) +
- 2 * PAILLIER_BITS / 8 * ks->num_peers +
- 1 * PAILLIER_BITS / 8 * ks->threshold);
+ sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers +
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->threshold);
element = GNUNET_malloc (sizeof (struct GNUNET_SET_Element) + element_size);
element->size = element_size;
d = (void *) element->data;
d->peer = my_peer;
+ // start inserting vector elements
+ // after the fixed part of the element's data
pos = (void *) &d[1];
last_pos = pos + element_size;
- // exponentiated pre-shares
- for (i = 0; i < ks->num_peers; i++)
- {
- ptrdiff_t remaining = last_pos - pos;
- GNUNET_assert (remaining > 0);
- gcry_mpi_set_ui (idx, i);
- // evaluate the polynomial
- horner_eval (v, ks->presecret_polynomial, ks->threshold, idx, elgamal_p);
- // take g to the result
- gcry_mpi_powm (v, elgamal_g, v, elgamal_p);
- gcry_mpi_print (GCRYMPI_FMT_USG, pos, (size_t) remaining, NULL, v);
- pos += PAILLIER_BITS / 8;
- }
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed exp preshares\n",
+ ks->local_peer_idx);
// encrypted pre-shares
- for (i = 0; i < ks->num_peers; i++)
+ // and fair encryption proof
{
- ptrdiff_t remaining = last_pos - pos;
- GNUNET_assert (remaining > 0);
- if (GNUNET_NO == ks->info[i].round1_valid)
- gcry_mpi_set_ui (v, 0);
- else
- paillier_encrypt (v, ks->presecret_polynomial[0],
- ks->info[i].paillier_g, ks->info[i].paillier_g);
- gcry_mpi_print (GCRYMPI_FMT_USG, pos, (size_t) remaining, NULL, v);
- pos += PAILLIER_BITS / 8;
+ for (i = 0; i < ks->num_peers; i++)
+ {
+ ptrdiff_t remaining = last_pos - pos;
+ struct GNUNET_SECRETSHARING_FairEncryption *fe = (void *) pos;
+
+ GNUNET_assert (remaining > 0);
+ memset (fe, 0, sizeof *fe);
+ if (GNUNET_YES == ks->info[i].round1_valid)
+ {
+ gcry_mpi_set_ui (idx, i + 1);
+ // evaluate the polynomial
+ horner_eval (v, ks->presecret_polynomial, ks->threshold, idx, elgamal_q);
+ // encrypt the result
+ encrypt_fair (v, &ks->info[i].paillier_public_key, fe);
+ }
+ pos += sizeof *fe;
+ }
}
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed enc preshares\n",
+ ks->local_peer_idx);
+
// exponentiated coefficients
for (i = 0; i < ks->threshold; i++)
{
ptrdiff_t remaining = last_pos - pos;
GNUNET_assert (remaining > 0);
gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[i], elgamal_p);
- gcry_mpi_print (GCRYMPI_FMT_USG, pos, (size_t) remaining, NULL, v);
- pos += PAILLIER_BITS / 8;
+ GNUNET_CRYPTO_mpi_print_unsigned (pos, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, v);
+ pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8;
}
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: computed exp coefficients\n",
+ ks->local_peer_idx);
+
+
d->purpose.size = htonl (element_size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData, purpose));
d->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG2);
- GNUNET_CRYPTO_eddsa_sign (my_peer_private_key, &d->purpose, &d->signature);
+ GNUNET_assert (GNUNET_OK ==
+ GNUNET_CRYPTO_eddsa_sign (my_peer_private_key,
+ &d->purpose,
+ &d->signature));
GNUNET_CONSENSUS_insert (ks->consensus, element, NULL, NULL);
GNUNET_free (element); /* FIXME: maybe stack-allocate instead? */
}
+static gcry_mpi_t
+keygen_reveal_get_exp_coeff (struct KeygenSession *ks,
+ const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
+ unsigned int idx)
+{
+ unsigned char *pos;
+ gcry_mpi_t exp_coeff;
+
+ GNUNET_assert (idx < ks->threshold);
+
+ pos = (void *) &d[1];
+ // skip encrypted pre-shares
+ pos += sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers;
+ // skip exp. coeffs we are not interested in
+ pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * idx;
+ // the first exponentiated coefficient is the public key share
+ GNUNET_CRYPTO_mpi_scan_unsigned (&exp_coeff, pos, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ return exp_coeff;
+}
+
+
+static struct GNUNET_SECRETSHARING_FairEncryption *
+keygen_reveal_get_enc_preshare (struct KeygenSession *ks,
+ const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
+ unsigned int idx)
+{
+ unsigned char *pos;
+
+ GNUNET_assert (idx < ks->num_peers);
+
+ pos = (void *) &d[1];
+ // skip encrypted pre-shares we're not interested in
+ pos += sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * idx;
+ return (struct GNUNET_SECRETSHARING_FairEncryption *) pos;
+}
+
+
+static gcry_mpi_t
+keygen_reveal_get_exp_preshare (struct KeygenSession *ks,
+ const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
+ unsigned int idx)
+{
+ gcry_mpi_t exp_preshare;
+ struct GNUNET_SECRETSHARING_FairEncryption *fe;
+
+ GNUNET_assert (idx < ks->num_peers);
+ fe = keygen_reveal_get_enc_preshare (ks, d, idx);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&exp_preshare, fe->h, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ return exp_preshare;
+}
+
+
static void
keygen_round2_new_element (void *cls,
const struct GNUNET_SET_Element *element)
struct KeygenSession *ks = cls;
const struct GNUNET_SECRETSHARING_KeygenRevealData *d;
struct KeygenPeerInfo *info;
- unsigned char *pos;
- gcry_mpi_t c;
size_t expected_element_size;
+ unsigned int j;
+ int cmp_result;
+ gcry_mpi_t tmp;
+ gcry_mpi_t public_key_share;
+ gcry_mpi_t preshare;
if (NULL == element)
{
}
expected_element_size = (sizeof (struct GNUNET_SECRETSHARING_KeygenRevealData) +
- 2 * PAILLIER_BITS / 8 * ks->num_peers +
- 1 * PAILLIER_BITS / 8 * ks->threshold);
+ sizeof (struct GNUNET_SECRETSHARING_FairEncryption) * ks->num_peers +
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->threshold);
if (element->size != expected_element_size)
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "keygen round2 data with wrong size (%u) in consensus, "
- " %u expected\n",
- element->size, expected_element_size);
+ "keygen round2 data with wrong size (%u) in consensus, %u expected\n",
+ (unsigned int) element->size,
+ (unsigned int) expected_element_size);
return;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO, "got round2 element\n");
+ if (ntohl (d->purpose.size) !=
+ element->size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData, purpose))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen reveal data with wrong signature purpose size in consensus\n");
+ return;
+ }
- pos = (void *) &d[1];
- // skip exponentiated pre-shares
- pos += PAILLIER_BITS / 8 * ks->num_peers;
- // skip encrypted pre-shares
- pos += PAILLIER_BITS / 8 * ks->num_peers;
- // the first exponentiated coefficient is the public key share
- GNUNET_assert (0 == gcry_mpi_scan (&info->public_key_share, GCRYMPI_FMT_USG,
- pos, PAILLIER_BITS / 8, NULL));
+ if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG2,
+ &d->purpose, &d->signature, &d->peer.public_key))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen reveal data with invalid signature in consensus\n");
+ return;
+ }
- pos = (void *) &d[1];
- // skip exp. pre-shares
- pos += PAILLIER_BITS / 8 * ks->num_peers;
- // skip to the encrypted value for our peer
- pos += PAILLIER_BITS / 8 * ks->local_peer_idx;
+ public_key_share = keygen_reveal_get_exp_coeff (ks, d, 0);
+ info->preshare_commitment = keygen_reveal_get_exp_preshare (ks, d, ks->local_peer_idx);
- GNUNET_assert (0 == gcry_mpi_scan (&c, GCRYMPI_FMT_USG,
- pos, PAILLIER_BITS / 8, NULL));
+ if (NULL == ks->public_key)
+ {
+ GNUNET_assert (NULL != (ks->public_key = gcry_mpi_new (0)));
+ gcry_mpi_set_ui (ks->public_key, 1);
+ }
+ gcry_mpi_mulm (ks->public_key, ks->public_key, public_key_share, elgamal_p);
- GNUNET_assert (0 != (info->decrypted_preshare = mpi_new (0)));
+ gcry_mpi_release (public_key_share);
+ public_key_share = NULL;
- paillier_decrypt (info->decrypted_preshare, c, ks->paillier_lambda, ks->paillier_mu,
- ks->info[ks->local_peer_idx].paillier_n);
+ {
+ struct GNUNET_SECRETSHARING_FairEncryption *fe = keygen_reveal_get_enc_preshare (ks, d, ks->local_peer_idx);
+ GNUNET_assert (NULL != (preshare = gcry_mpi_new (0)));
+ GNUNET_CRYPTO_paillier_decrypt (&ks->paillier_private_key,
+ &ks->info[ks->local_peer_idx].paillier_public_key,
+ &fe->c,
+ preshare);
+
+ // FIXME: not doing the restoration is less expensive
+ restore_fair (&ks->info[ks->local_peer_idx].paillier_public_key,
+ fe,
+ preshare,
+ preshare);
+ }
- // TODO: validate zero knowledge proofs
+ GNUNET_assert (NULL != (tmp = gcry_mpi_new (0)));
+ gcry_mpi_powm (tmp, elgamal_g, preshare, elgamal_p);
- if (d->purpose.size !=
- htons (element->size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData, purpose)))
+ cmp_result = gcry_mpi_cmp (tmp, info->preshare_commitment);
+ gcry_mpi_release (tmp);
+ tmp = NULL;
+ if (0 != cmp_result)
{
- GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen reveal data with wrong signature purpose size in consensus\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: Got invalid presecret from P%u\n",
+ (unsigned int) ks->local_peer_idx, (unsigned int) (info - ks->info));
return;
}
- if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG2,
- &d->purpose, &d->signature, &d->peer.public_key))
+ if (NULL == ks->my_share)
{
- GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "keygen reveal data with invalid signature in consensus\n");
- return;
+ GNUNET_assert (NULL != (ks->my_share = gcry_mpi_new (0)));
}
-
+ gcry_mpi_addm (ks->my_share, ks->my_share, preshare, elgamal_q);
+
+ for (j = 0; j < ks->num_peers; j++)
+ {
+ gcry_mpi_t presigma;
+ if (NULL == ks->info[j].sigma)
+ {
+ GNUNET_assert (NULL != (ks->info[j].sigma = gcry_mpi_new (0)));
+ gcry_mpi_set_ui (ks->info[j].sigma, 1);
+ }
+ presigma = keygen_reveal_get_exp_preshare (ks, d, j);
+ gcry_mpi_mulm (ks->info[j].sigma, ks->info[j].sigma, presigma, elgamal_p);
+ gcry_mpi_release (presigma);
+ }
+
+ gcry_mpi_t prod;
+ GNUNET_assert (NULL != (prod = gcry_mpi_new (0)));
+ gcry_mpi_t j_to_k;
+ GNUNET_assert (NULL != (j_to_k = gcry_mpi_new (0)));
+ // validate that the polynomial sharing matches the additive sharing
+ for (j = 0; j < ks->num_peers; j++)
+ {
+ unsigned int k;
+ int cmp_result;
+ gcry_mpi_t exp_preshare;
+ gcry_mpi_set_ui (prod, 1);
+ for (k = 0; k < ks->threshold; k++)
+ {
+ // Using pow(double,double) is a bit sketchy.
+ // We count players from 1, but shares from 0.
+ gcry_mpi_t tmp;
+ gcry_mpi_set_ui (j_to_k, (unsigned int) pow(j+1, k));
+ tmp = keygen_reveal_get_exp_coeff (ks, d, k);
+ gcry_mpi_powm (tmp, tmp, j_to_k, elgamal_p);
+ gcry_mpi_mulm (prod, prod, tmp, elgamal_p);
+ gcry_mpi_release (tmp);
+ }
+ exp_preshare = keygen_reveal_get_exp_preshare (ks, d, j);
+ gcry_mpi_mod (exp_preshare, exp_preshare, elgamal_p);
+ cmp_result = gcry_mpi_cmp (prod, exp_preshare);
+ gcry_mpi_release (exp_preshare);
+ exp_preshare = NULL;
+ if (0 != cmp_result)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: reveal data from P%u incorrect\n",
+ ks->local_peer_idx, j);
+ /* no need for further verification, round2 stays invalid ... */
+ return;
+ }
+ }
+
+ // TODO: verify proof of fair encryption (once implemented)
+ for (j = 0; j < ks->num_peers; j++)
+ {
+ struct GNUNET_SECRETSHARING_FairEncryption *fe = keygen_reveal_get_enc_preshare (ks, d, j);
+ if (GNUNET_YES != verify_fair (&ks->info[j].paillier_public_key, fe))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: reveal data from P%u incorrect (fair encryption)\n",
+ ks->local_peer_idx, j);
+ return;
+ }
+
+ }
+
info->round2_valid = GNUNET_YES;
+
+ gcry_mpi_release (preshare);
+ gcry_mpi_release (prod);
+ gcry_mpi_release (j_to_k);
}
GNUNET_CONSENSUS_destroy (ks->consensus);
ks->consensus = GNUNET_CONSENSUS_create (cfg, ks->num_peers, ks->peers, &ks->session_id,
+ time_between (ks->start_time, ks->deadline, 1, 2),
+ ks->deadline,
keygen_round2_new_element, ks);
insert_round2_element (ks);
GNUNET_CONSENSUS_conclude (ks->consensus,
- /* last round, thus conclude at DKG deadline */
- ks->deadline,
keygen_round2_conclude,
ks);
}
// g^a_{i,0}
gcry_mpi_t v;
// big-endian representation of 'v'
- unsigned char v_data[PAILLIER_BITS / 8];
+ unsigned char v_data[GNUNET_SECRETSHARING_ELGAMAL_BITS / 8];
element = GNUNET_malloc (sizeof *element + sizeof *d);
d = (void *) &element[1];
element->data = d;
element->size = sizeof *d;
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "alloc'd size %u\n", sizeof *element + sizeof *d);
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "element size %u\n", element->size);
-
-
d->peer = my_peer;
- GNUNET_assert (0 != (v = gcry_mpi_new (PAILLIER_BITS)));
+ GNUNET_assert (0 != (v = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[0], elgamal_p);
- GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
- v_data, PAILLIER_BITS / 8, NULL,
- v));
-
- GNUNET_CRYPTO_hash (v_data, PAILLIER_BITS / 8, &d->commitment);
+ GNUNET_CRYPTO_mpi_print_unsigned (v_data, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, v);
- /*
+ GNUNET_CRYPTO_hash (v_data, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, &d->commitment);
- GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
- (unsigned char *) d->pubkey.g, PAILLIER_BITS / 8, NULL,
- ks->info[ks->local_peer_idx].paillier_g));
-
- GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
- (unsigned char *) d->pubkey.n, PAILLIER_BITS / 8, NULL,
- ks->info[ks->local_peer_idx].paillier_n));
-
- */
+ d->pubkey = ks->info[ks->local_peer_idx].paillier_public_key;
d->purpose.size = htonl ((sizeof *d) - offsetof (struct GNUNET_SECRETSHARING_KeygenCommitData, purpose));
d->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DKG1);
- GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_eddsa_sign (my_peer_private_key, &d->purpose, &d->signature));
+ GNUNET_assert (GNUNET_OK ==
+ GNUNET_CRYPTO_eddsa_sign (my_peer_private_key,
+ &d->purpose,
+ &d->signature));
GNUNET_CONSENSUS_insert (ks->consensus, element, NULL, NULL);
}
+/**
+ * Check that @a msg is well-formed.
+ *
+ * @param cls identification of the client
+ * @param msg the actual message
+ * @return #GNUNET_OK if @a msg is well-formed
+ */
+static int
+check_client_keygen (void *cls,
+ const struct GNUNET_SECRETSHARING_CreateMessage *msg)
+{
+ unsigned int num_peers = ntohs (msg->num_peers);
+
+ if (ntohs (msg->header.size) - sizeof (*msg) !=
+ num_peers * sizeof (struct GNUNET_PeerIdentity))
+ {
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
+ }
+ return GNUNET_OK;
+}
+
+
/**
* Functions with this signature are called whenever a message is
* received.
*
- * @param cls closure
- * @param client identification of the client
- * @param message the actual message
+ * @param cls identification of the client
+ * @param msg the actual message
*/
-static void handle_client_keygen (void *cls,
- struct GNUNET_SERVER_Client *client,
- const struct GNUNET_MessageHeader
- *message)
+static void
+handle_client_keygen (void *cls,
+ const struct GNUNET_SECRETSHARING_CreateMessage *msg)
{
- const struct GNUNET_SECRETSHARING_CreateMessage *msg =
- (const struct GNUNET_SECRETSHARING_CreateMessage *) message;
+ struct ClientState *cs = cls;
struct KeygenSession *ks;
- unsigned int i;
-
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "client requested key generation\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "client requested key generation\n");
+ if (NULL != cs->keygen_session)
+ {
+ GNUNET_break (0);
+ GNUNET_SERVICE_client_drop (cs->client);
+ return;
+ }
ks = GNUNET_new (struct KeygenSession);
-
- /* FIXME: check if client already has some session */
-
- GNUNET_CONTAINER_DLL_insert (keygen_sessions_head, keygen_sessions_tail, ks);
-
- ks->client = client;
- ks->client_mq = GNUNET_MQ_queue_for_server_client (client);
-
+ ks->cs = cs;
+ cs->keygen_session = ks;
ks->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
ks->threshold = ntohs (msg->threshold);
ks->num_peers = ntohs (msg->num_peers);
- ks->peers = normalize_peers ((struct GNUNET_PeerIdentity *) &msg[1], ks->num_peers,
- &ks->num_peers, &ks->local_peer_idx);
+ ks->peers = normalize_peers ((struct GNUNET_PeerIdentity *) &msg[1],
+ ks->num_peers,
+ &ks->num_peers,
+ &ks->local_peer_idx);
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "first round of consensus with %u peers\n", ks->num_peers);
- ks->consensus = GNUNET_CONSENSUS_create (cfg, ks->num_peers, ks->peers, &msg->session_id,
- keygen_round1_new_element, ks);
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "first round of consensus with %u peers\n",
+ ks->num_peers);
+ ks->consensus = GNUNET_CONSENSUS_create (cfg,
+ ks->num_peers,
+ ks->peers,
+ &msg->session_id,
+ GNUNET_TIME_absolute_ntoh (msg->start),
+ GNUNET_TIME_absolute_ntoh (msg->deadline),
+ keygen_round1_new_element,
+ ks);
- ks->info = GNUNET_malloc (ks->num_peers * sizeof (struct KeygenPeerInfo));
+ ks->info = GNUNET_new_array (ks->num_peers,
+ struct KeygenPeerInfo);
- for (i = 0; i < ks->num_peers; i++)
+ for (unsigned int i = 0; i < ks->num_peers; i++)
ks->info[i].peer = ks->peers[i];
- GNUNET_assert (0 != (ks->info[ks->local_peer_idx].paillier_g = mpi_new (0)));
- GNUNET_assert (0 != (ks->info[ks->local_peer_idx].paillier_n = mpi_new (0)));
- GNUNET_assert (0 != (ks->paillier_lambda = mpi_new (0)));
- GNUNET_assert (0 != (ks->paillier_mu = mpi_new (0)));
-
- paillier_create (ks->info[ks->local_peer_idx].paillier_g,
- ks->info[ks->local_peer_idx].paillier_n,
- ks->paillier_lambda,
- ks->paillier_mu);
-
+ GNUNET_CRYPTO_paillier_create (&ks->info[ks->local_peer_idx].paillier_public_key,
+ &ks->paillier_private_key);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "P%u: Generated paillier key pair\n",
+ ks->local_peer_idx);
generate_presecret_polynomial (ks);
-
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "P%u: Generated presecret polynomial\n",
+ ks->local_peer_idx);
insert_round1_element (ks);
-
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "starting conclude of round 1\n");
-
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "P%u: Concluding for round 1\n",
+ ks->local_peer_idx);
GNUNET_CONSENSUS_conclude (ks->consensus,
- /* half the overall time */
- time_between (ks->start_time, ks->deadline, 1, 2),
keygen_round1_conclude,
ks);
-
- GNUNET_SERVER_receive_done (client, GNUNET_OK);
+ GNUNET_SERVICE_client_continue (cs->client);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "P%u: Waiting for round 1 elements ...\n",
+ ks->local_peer_idx);
}
gcry_mpi_t m;
gcry_mpi_t tmp;
gcry_mpi_t c_2;
+ gcry_mpi_t prod;
unsigned int *indices;
unsigned int num;
unsigned int i;
unsigned int j;
+ GNUNET_CONSENSUS_destroy (ds->consensus);
+ ds->consensus = NULL;
+
GNUNET_assert (0 != (lagrange = gcry_mpi_new (0)));
GNUNET_assert (0 != (m = gcry_mpi_new (0)));
GNUNET_assert (0 != (tmp = gcry_mpi_new (0)));
+ GNUNET_assert (0 != (prod = gcry_mpi_new (0)));
num = 0;
for (i = 0; i < ds->share->num_peers; i++)
if (NULL != ds->info[i].partial_decryption)
num++;
- indices = GNUNET_malloc (num * sizeof (unsigned int));
+ indices = GNUNET_new_array (num,
+ unsigned int);
j = 0;
for (i = 0; i < ds->share->num_peers; i++)
if (NULL != ds->info[i].partial_decryption)
- indices[j++] = ds->info[i].real_index;
+ indices[j++] = ds->info[i].original_index;
- gcry_mpi_set_ui (m, 1);
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "P%u: decrypt conclude, with %u peers\n",
+ ds->share->my_peer,
+ num);
+ gcry_mpi_set_ui (prod, 1);
for (i = 0; i < num; i++)
{
+
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "P%u: index of %u: %u\n",
+ ds->share->my_peer, i, indices[i]);
compute_lagrange_coefficient (lagrange, indices[i], indices, num);
- // w_j^{\lambda_j}
+ // w_i^{\lambda_i}
gcry_mpi_powm (tmp, ds->info[indices[i]].partial_decryption, lagrange, elgamal_p);
- gcry_mpi_mulm (m, m, tmp, elgamal_p);
- }
- GNUNET_assert (0 == gcry_mpi_scan (&c_2, GCRYMPI_FMT_USG, ds->ciphertext.c2_bits,
- PAILLIER_BITS / 8, NULL));
+ // product of all exponentiated partiel decryptions ...
+ gcry_mpi_mulm (prod, prod, tmp, elgamal_p);
+ }
- // m <- c_2 / m
- gcry_mpi_invm (m, m, elgamal_p);
- gcry_mpi_mulm (m, c_2, m, elgamal_p);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&c_2, ds->ciphertext.c2_bits, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_assert (0 != gcry_mpi_invm (prod, prod, elgamal_p));
+ gcry_mpi_mulm (m, c_2, prod, elgamal_p);
ev = GNUNET_MQ_msg (msg, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT_DONE);
- print_field_element (&msg->plaintext, m);
+ GNUNET_CRYPTO_mpi_print_unsigned (&msg->plaintext, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, m);
msg->success = htonl (1);
- GNUNET_MQ_send (ds->client_mq, ev);
+ GNUNET_MQ_send (ds->cs->mq,
+ ev);
+
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO, "sent decrypt done to client\n");
+
+ GNUNET_free (indices);
+
+ gcry_mpi_release(lagrange);
+ gcry_mpi_release(m);
+ gcry_mpi_release(tmp);
+ gcry_mpi_release(prod);
+ gcry_mpi_release(c_2);
// FIXME: what if not enough peers participated?
}
+/**
+ * Get a string representation of an MPI.
+ * The caller must free the returned string.
+ *
+ * @param mpi mpi to convert to a string
+ * @return string representation of @a mpi, must be free'd by the caller
+ */
+static char *
+mpi_to_str (gcry_mpi_t mpi)
+{
+ unsigned char *buf;
+
+ GNUNET_assert (0 == gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buf, NULL, mpi));
+ return (char *) buf;
+}
+
+
/**
* Called when a new partial decryption arrives.
*/
struct DecryptSession *session = cls;
const struct GNUNET_SECRETSHARING_DecryptData *d;
struct DecryptPeerInfo *info;
+ struct GNUNET_HashCode challenge_hash;
+
+ /* nizk response */
+ gcry_mpi_t r;
+ /* nizk challenge */
+ gcry_mpi_t challenge;
+ /* nizk commit1, g^\beta */
+ gcry_mpi_t commit1;
+ /* nizk commit2, c_1^\beta */
+ gcry_mpi_t commit2;
+ /* homomorphic commitment to the peer's share,
+ * public key share */
+ gcry_mpi_t sigma;
+ /* partial decryption we received */
+ gcry_mpi_t w;
+ /* ciphertext component #1 */
+ gcry_mpi_t c1;
+ /* temporary variable (for comparision) #1 */
+ gcry_mpi_t tmp1;
+ /* temporary variable (for comparision) #2 */
+ gcry_mpi_t tmp2;
if (NULL == element)
{
d = element->data;
info = get_decrypt_peer_info (session, &d->peer);
-
+
if (NULL == info)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decrypt element from invalid peer (%s)\n",
if (NULL != info->partial_decryption)
{
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decrypt element duplicate\n",
- GNUNET_i2s (&d->peer));
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "decrypt element duplicate\n");
+ return;
+ }
+
+ if (0 != memcmp (&d->ciphertext, &session->ciphertext, sizeof (struct GNUNET_SECRETSHARING_Ciphertext)))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "P%u: got decrypt element with non-matching ciphertext from P%u\n",
+ (unsigned int) session->share->my_peer, (unsigned int) (info - session->info));
+
return;
}
- // FIXME: check NIZP first
- GNUNET_assert (0 == gcry_mpi_scan (&info->partial_decryption,
- GCRYMPI_FMT_USG, &d->partial_decryption, PAILLIER_BITS / 8, NULL));
+ GNUNET_CRYPTO_hash (offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext) + (char *) d,
+ offsetof (struct GNUNET_SECRETSHARING_DecryptData, nizk_response) -
+ offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext),
+ &challenge_hash);
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&challenge, &challenge_hash,
+ sizeof (struct GNUNET_HashCode));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&sigma, &session->share->sigmas[info - session->info],
+ sizeof (struct GNUNET_SECRETSHARING_FieldElement));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&c1, session->ciphertext.c1_bits,
+ sizeof (struct GNUNET_SECRETSHARING_FieldElement));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&commit1, &d->nizk_commit1,
+ sizeof (struct GNUNET_SECRETSHARING_FieldElement));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&commit2, &d->nizk_commit2,
+ sizeof (struct GNUNET_SECRETSHARING_FieldElement));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&r, &d->nizk_response,
+ sizeof (struct GNUNET_SECRETSHARING_FieldElement));
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&w, &d->partial_decryption,
+ sizeof (struct GNUNET_SECRETSHARING_FieldElement));
+
+ GNUNET_assert (NULL != (tmp1 = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (tmp2 = gcry_mpi_new (0)));
+
+ // tmp1 = g^r
+ gcry_mpi_powm (tmp1, elgamal_g, r, elgamal_p);
+
+ // tmp2 = g^\beta * \sigma^challenge
+ gcry_mpi_powm (tmp2, sigma, challenge, elgamal_p);
+ gcry_mpi_mulm (tmp2, tmp2, commit1, elgamal_p);
+
+ if (0 != gcry_mpi_cmp (tmp1, tmp2))
+ {
+ char *tmp1_str;
+ char *tmp2_str;
+
+ tmp1_str = mpi_to_str (tmp1);
+ tmp2_str = mpi_to_str (tmp2);
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+ "P%u: Received invalid partial decryption from P%u (eqn 1), expected %s got %s\n",
+ session->share->my_peer,
+ (unsigned int) (info - session->info),
+ tmp1_str,
+ tmp2_str);
+ GNUNET_free (tmp1_str);
+ GNUNET_free (tmp2_str);
+ goto cleanup;
+ }
+
+
+ gcry_mpi_powm (tmp1, c1, r, elgamal_p);
+
+ gcry_mpi_powm (tmp2, w, challenge, elgamal_p);
+ gcry_mpi_mulm (tmp2, tmp2, commit2, elgamal_p);
+
+
+ if (0 != gcry_mpi_cmp (tmp1, tmp2))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+ "P%u: Received invalid partial decryption from P%u (eqn 2)\n",
+ session->share->my_peer,
+ (unsigned int) (info - session->info));
+ goto cleanup;
+ }
+
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&info->partial_decryption, &d->partial_decryption,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+cleanup:
+ gcry_mpi_release (tmp1);
+ gcry_mpi_release (tmp2);
+ gcry_mpi_release (sigma);
+ gcry_mpi_release (commit1);
+ gcry_mpi_release (commit2);
+ gcry_mpi_release (r);
+ gcry_mpi_release (w);
+ gcry_mpi_release (challenge);
+ gcry_mpi_release (c1);
}
+
static void
insert_decrypt_element (struct DecryptSession *ds)
{
struct GNUNET_SECRETSHARING_DecryptData d;
struct GNUNET_SET_Element element;
- gcry_mpi_t x;
+ /* our share */
gcry_mpi_t s;
+ /* partial decryption with our share */
+ gcry_mpi_t w;
+ /* first component of the elgamal ciphertext */
+ gcry_mpi_t c1;
+ /* nonce for dlog zkp */
+ gcry_mpi_t beta;
+ gcry_mpi_t tmp;
+ gcry_mpi_t challenge;
+ gcry_mpi_t sigma;
+ struct GNUNET_HashCode challenge_hash;
- GNUNET_assert (0 == gcry_mpi_scan (&x, GCRYMPI_FMT_USG, ds->ciphertext.c1_bits, PAILLIER_BITS / 8, NULL));
- GNUNET_assert (0 == gcry_mpi_scan (&s, GCRYMPI_FMT_USG, &ds->share->my_share, PAILLIER_BITS / 8, NULL));
+ /* make vagrind happy until we implement the real deal ... */
+ memset (&d, 0, sizeof d);
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: Inserting decrypt element\n",
+ ds->share->my_peer);
+
+ GNUNET_assert (ds->share->my_peer < ds->share->num_peers);
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&c1, &ds->ciphertext.c1_bits,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&s, &ds->share->my_share,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ GNUNET_CRYPTO_mpi_scan_unsigned (&sigma, &ds->share->sigmas[ds->share->my_peer],
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+
+ GNUNET_assert (NULL != (w = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (beta = gcry_mpi_new (0)));
+ GNUNET_assert (NULL != (tmp = gcry_mpi_new (0)));
+
+ // FIXME: unnecessary, remove once crypto works
+ gcry_mpi_powm (tmp, elgamal_g, s, elgamal_p);
+ if (0 != gcry_mpi_cmp (tmp, sigma))
+ {
+ char *sigma_str = mpi_to_str (sigma);
+ char *tmp_str = mpi_to_str (tmp);
+ char *s_str = mpi_to_str (s);
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Share of P%u is invalid, ref sigma %s, "
+ "computed sigma %s, s %s\n",
+ ds->share->my_peer,
+ sigma_str, tmp_str, s_str);
+ GNUNET_free (sigma_str);
+ GNUNET_free (tmp_str);
+ GNUNET_free (s_str);
+ }
- gcry_mpi_powm (x, x, s, elgamal_p);
+ gcry_mpi_powm (w, c1, s, elgamal_p);
element.data = (void *) &d;
element.size = sizeof (struct GNUNET_SECRETSHARING_DecryptData);
+ element.element_type = 0;
+ d.ciphertext = ds->ciphertext;
d.peer = my_peer;
- d.purpose.size = htonl (element.size - offsetof (struct GNUNET_SECRETSHARING_KeygenRevealData, purpose));
+ GNUNET_CRYPTO_mpi_print_unsigned (&d.partial_decryption, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, w);
+
+ // create the zero knowledge proof
+ // randomly choose beta such that 0 < beta < q
+ do
+ {
+ gcry_mpi_randomize (beta, GNUNET_SECRETSHARING_ELGAMAL_BITS - 1, GCRY_WEAK_RANDOM);
+ } while ((gcry_mpi_cmp_ui (beta, 0) == 0) || (gcry_mpi_cmp (beta, elgamal_q) >= 0));
+ // tmp = g^beta
+ gcry_mpi_powm (tmp, elgamal_g, beta, elgamal_p);
+ GNUNET_CRYPTO_mpi_print_unsigned (&d.nizk_commit1, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, tmp);
+ // tmp = (c_1)^beta
+ gcry_mpi_powm (tmp, c1, beta, elgamal_p);
+ GNUNET_CRYPTO_mpi_print_unsigned (&d.nizk_commit2, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, tmp);
+
+ // the challenge is the hash of everything up to the response
+ GNUNET_CRYPTO_hash (offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext) + (char *) &d,
+ offsetof (struct GNUNET_SECRETSHARING_DecryptData, nizk_response) -
+ offsetof (struct GNUNET_SECRETSHARING_DecryptData, ciphertext),
+ &challenge_hash);
+
+ GNUNET_CRYPTO_mpi_scan_unsigned (&challenge, &challenge_hash,
+ sizeof (struct GNUNET_HashCode));
+
+ // compute the response in tmp,
+ // tmp = (c * s + beta) mod q
+ gcry_mpi_mulm (tmp, challenge, s, elgamal_q);
+ gcry_mpi_addm (tmp, tmp, beta, elgamal_q);
+
+ GNUNET_CRYPTO_mpi_print_unsigned (&d.nizk_response, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, tmp);
+
+ d.purpose.size = htonl (element.size - offsetof (struct GNUNET_SECRETSHARING_DecryptData, purpose));
d.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_SECRETSHARING_DECRYPTION);
- GNUNET_CRYPTO_eddsa_sign (my_peer_private_key, &d.purpose, &d.signature);
- print_field_element (&d.partial_decryption, x);
+ GNUNET_assert (GNUNET_OK ==
+ GNUNET_CRYPTO_eddsa_sign (my_peer_private_key,
+ &d.purpose,
+ &d.signature));
GNUNET_CONSENSUS_insert (ds->consensus, &element, NULL, NULL);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "P%u: Inserting decrypt element done!\n",
+ ds->share->my_peer);
+
+ gcry_mpi_release (s);
+ gcry_mpi_release (w);
+ gcry_mpi_release (c1);
+ gcry_mpi_release (beta);
+ gcry_mpi_release (tmp);
+ gcry_mpi_release (challenge);
+ gcry_mpi_release (sigma);
+}
+
+
+/**
+ * Check that @a msg is well-formed.
+ *
+ * @param cls identification of the client
+ * @param msg the actual message
+ * @return #GNUNET_OK (check deferred a bit)
+ */
+static int
+check_client_decrypt (void *cls,
+ const struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg)
+{
+ /* we check later, it's complicated */
+ return GNUNET_OK;
}
* Functions with this signature are called whenever a message is
* received.
*
- * @param cls closure
- * @param client identification of the client
- * @param message the actual message
+ * @param cls identification of the client
+ * @param msg the actual message
*/
-static void handle_client_decrypt (void *cls,
- struct GNUNET_SERVER_Client *client,
- const struct GNUNET_MessageHeader
- *message)
+static void
+handle_client_decrypt (void *cls,
+ const struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg)
{
- const struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg =
- (const void *) message;
+ struct ClientState *cs = cls;
struct DecryptSession *ds;
struct GNUNET_HashCode session_id;
+ if (NULL != cs->decrypt_session)
+ {
+ GNUNET_break (0);
+ GNUNET_SERVICE_client_drop (cs->client);
+ return;
+ }
ds = GNUNET_new (struct DecryptSession);
- // FIXME: check if session already exists
- GNUNET_CONTAINER_DLL_insert (decrypt_sessions_head, decrypt_sessions_tail, ds);
- ds->client = client;
- ds->client_mq = GNUNET_MQ_queue_for_server_client (client);
+ cs->decrypt_session = ds;
+ ds->cs = cs;
+ ds->start = GNUNET_TIME_absolute_ntoh (msg->start);
ds->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
ds->ciphertext = msg->ciphertext;
- ds->share = GNUNET_SECRETSHARING_share_read (&msg[1], ntohs (msg->header.size) - sizeof *msg, NULL);
- // FIXME: probably should be break rather than assert
- GNUNET_assert (NULL != ds->share);
-
- // FIXME: this is probably sufficient, but kdf/hash with all values would be nicer ...
- GNUNET_CRYPTO_hash (&msg->ciphertext, sizeof (struct GNUNET_SECRETSHARING_Ciphertext), &session_id);
+ ds->share = GNUNET_SECRETSHARING_share_read (&msg[1],
+ ntohs (msg->header.size) - sizeof (*msg),
+ NULL);
+ if (NULL == ds->share)
+ {
+ GNUNET_break (0);
+ GNUNET_SERVICE_client_drop (cs->client);
+ return;
+ }
+ /* FIXME: this is probably sufficient, but kdf/hash with all values would be nicer ... */
+ GNUNET_CRYPTO_hash (&msg->ciphertext,
+ sizeof (struct GNUNET_SECRETSHARING_Ciphertext),
+ &session_id);
ds->consensus = GNUNET_CONSENSUS_create (cfg,
ds->share->num_peers,
ds->share->peers,
&session_id,
- decrypt_new_element,
+ ds->start,
+ ds->deadline,
+ &decrypt_new_element,
ds);
- insert_decrypt_element (ds);
- GNUNET_CONSENSUS_conclude (ds->consensus, ds->deadline, decrypt_conclude, ds);
+ ds->info = GNUNET_new_array (ds->share->num_peers,
+ struct DecryptPeerInfo);
+ for (unsigned int i = 0; i < ds->share->num_peers; i++)
+ {
+ ds->info[i].peer = ds->share->peers[i];
+ ds->info[i].original_index = ds->share->original_indices[i];
+ }
+ insert_decrypt_element (ds);
+ GNUNET_CONSENSUS_conclude (ds->consensus,
+ decrypt_conclude,
+ ds);
+ GNUNET_SERVICE_client_continue (cs->client);
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "decrypting with %u peers\n",
+ ds->share->num_peers);
}
static void
init_crypto_constants (void)
{
- /* 1024-bit safe prime */
- const char *elgamal_p_hex =
- "0x08a347d3d69e8b2dd7d1b12a08dfbccbebf4ca"
- "6f4269a0814e158a34312964d946b3ef22882317"
- "2bcf30fc08f772774cb404f9bc002a6f66b09a79"
- "d810d67c4f8cb3bedc6060e3c8ef874b1b64df71"
- "6c7d2b002da880e269438d5a776e6b5f253c8df5"
- "6a16b1c7ce58def07c03db48238aadfc52a354a2"
- "7ed285b0c1675cad3f3";
- /* 1023-bit Sophie Germain prime, q = (p-1)/2 */
- const char *elgamal_q_hex =
- "0x0451a3e9eb4f4596ebe8d895046fde65f5fa65"
- "37a134d040a70ac51a1894b26ca359f79144118b"
- "95e7987e047bb93ba65a027cde001537b3584d3c"
- "ec086b3e27c659df6e303071e477c3a58db26fb8"
- "b63e958016d4407134a1c6ad3bb735af929e46fa"
- "b50b58e3e72c6f783e01eda411c556fe2951aa51"
- "3f6942d860b3ae569f9";
- /* generator of the unique size q subgroup of Z_p^* */
- const char *elgamal_g_hex =
- "0x05c00c36d2e822950087ef09d8252994adc4e4"
- "8fe3ec70269f035b46063aff0c99b633fd64df43"
- "02442e1914c829a41505a275438871f365e91c12"
- "3d5303ef9e90f4b8cb89bf86cc9b513e74a72634"
- "9cfd9f953674fab5d511e1c078fc72d72b34086f"
- "c82b4b951989eb85325cb203ff98df76bc366bba"
- "1d7024c3650f60d0da";
-
GNUNET_assert (0 == gcry_mpi_scan (&elgamal_q, GCRYMPI_FMT_HEX,
- elgamal_q_hex, 0, NULL));
+ GNUNET_SECRETSHARING_ELGAMAL_Q_HEX, 0, NULL));
GNUNET_assert (0 == gcry_mpi_scan (&elgamal_p, GCRYMPI_FMT_HEX,
- elgamal_p_hex, 0, NULL));
+ GNUNET_SECRETSHARING_ELGAMAL_P_HEX, 0, NULL));
GNUNET_assert (0 == gcry_mpi_scan (&elgamal_g, GCRYMPI_FMT_HEX,
- elgamal_g_hex, 0, NULL));
+ GNUNET_SECRETSHARING_ELGAMAL_G_HEX, 0, NULL));
}
/**
- * Process template requests.
+ * Initialize secretsharing service.
*
* @param cls closure
- * @param server the initialized server
* @param c configuration to use
+ * @param service the initialized service
*/
static void
-run (void *cls, struct GNUNET_SERVER_Handle *server,
- const struct GNUNET_CONFIGURATION_Handle *c)
+run (void *cls,
+ const struct GNUNET_CONFIGURATION_Handle *c,
+ struct GNUNET_SERVICE_Handle *service)
{
- static const struct GNUNET_SERVER_MessageHandler handlers[] = {
- {handle_client_keygen, NULL, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_GENERATE, 0},
- {handle_client_decrypt, NULL, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT, 0},
- {NULL, NULL, 0, 0}
- };
cfg = c;
- srv = server;
my_peer_private_key = GNUNET_CRYPTO_eddsa_key_create_from_configuration (c);
if (NULL == my_peer_private_key)
{
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not access host private key\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "could not access host private key\n");
GNUNET_break (0);
GNUNET_SCHEDULER_shutdown ();
return;
}
init_crypto_constants ();
- if (GNUNET_OK != GNUNET_CRYPTO_get_peer_identity (cfg, &my_peer))
+ if (GNUNET_OK !=
+ GNUNET_CRYPTO_get_peer_identity (cfg,
+ &my_peer))
{
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not retrieve host identity\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "could not retrieve host identity\n");
GNUNET_break (0);
GNUNET_SCHEDULER_shutdown ();
return;
}
- GNUNET_SERVER_add_handlers (server, handlers);
- GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleanup_task,
- NULL);
+ GNUNET_SCHEDULER_add_shutdown (&cleanup_task,
+ NULL);
}
/**
- * The main function for the template service.
+ * Callback called when a client connects to the service.
*
- * @param argc number of arguments from the command line
- * @param argv command line arguments
- * @return 0 ok, 1 on error
+ * @param cls closure for the service
+ * @param c the new client that connected to the service
+ * @param mq the message queue used to send messages to the client
+ * @return @a c
*/
-int
-main (int argc, char *const *argv)
+static void *
+client_connect_cb (void *cls,
+ struct GNUNET_SERVICE_Client *c,
+ struct GNUNET_MQ_Handle *mq)
{
- return (GNUNET_OK ==
- GNUNET_SERVICE_run (argc, argv, "secretsharing",
- GNUNET_SERVICE_OPTION_NONE, &run, NULL)) ? 0 : 1;
+ struct ClientState *cs = GNUNET_new (struct ClientState);;
+
+ cs->client = c;
+ cs->mq = mq;
+ return cs;
+}
+
+
+/**
+ * Callback called when a client disconnected from the service
+ *
+ * @param cls closure for the service
+ * @param c the client that disconnected
+ * @param internal_cls should be equal to @a c
+ */
+static void
+client_disconnect_cb (void *cls,
+ struct GNUNET_SERVICE_Client *c,
+ void *internal_cls)
+{
+ struct ClientState *cs = internal_cls;
+
+ if (NULL != cs->keygen_session)
+ keygen_session_destroy (cs->keygen_session);
+
+ if (NULL != cs->decrypt_session)
+ decrypt_session_destroy (cs->decrypt_session);
+ GNUNET_free (cs);
}
+
+/**
+ * Define "main" method using service macro.
+ */
+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 ());
projects / oweals / gnunet.git / blobdiff