#include <gcrypt.h>
+#define EXTRA_CHECKS 1
+
+
/**
* Info about a peer in a key generation session.
*/
/**
* 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 decrypted
- * 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
* 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
struct GNUNET_HashCode session_id;
/**
- * lambda-component of our peer's paillier private key.
- */
- gcry_mpi_t paillier_lambda;
-
- /**
- * mu-component of our peer's paillier private key.
+ * Paillier private key of our peer.
*/
- 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;
+
+ /**
+ * Share of our peer. Once preshares from other peers are received, they
+ * will be added to 'my'share.
+ */
+ gcry_mpi_t my_share;
+
+ /**
+ * Public key, will be updated when a round2 element arrives.
+ */
+ gcry_mpi_t public_key;
};
*/
struct GNUNET_MQ_Handle *client_mq;
+ /**
+ * When should we start communicating for decryption?
+ */
+ struct GNUNET_TIME_Absolute start;
+
/**
* When would we like the ciphertext to be
* decrypted?
static struct GNUNET_SERVER_Handle *srv;
-/**
- * If target != size, move @a target bytes to the end of the size-sized
- * buffer and zero out the first @a target - @a size bytes.
- *
- * @param buf original buffer
- * @param size number of bytes in @a buf
- * @param target target size of the buffer
- */
-static void
-adjust (unsigned char *buf,
- size_t size,
- size_t target)
-{
- if (size < target)
- {
- memmove (&buf[target - size], buf, size);
- memset (buf, 0, target - size);
- }
-}
-
-
-/**
- * Print an MPI to a buffer, so that is contains the MPI's
- * the little endian representation of size @a size.
- *
- * @param buf buffer to write to
- * @param x mpi to be written in the buffer
- * @param size how many bytes should the little endian binary
- * representation of @a x use?
- */
-static void
-print_mpi_fixed (void *buf, gcry_mpi_t x, size_t size)
-{
- size_t written;
- GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
- buf, size, &written,
- x));
- adjust (buf, written, size);
-}
-
-
/**
* 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
+ * @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 struct KeygenPeerInfo *
get_keygen_peer_info (const struct KeygenSession *ks,
/**
* Get the peer info belonging to a peer identity in a decrypt session.
*
- * @param ks the decrypt session
- * @param peer the peer identity
- * @return the decrypt peer info, or NULL if the peer could not be found
+ * @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++)
/**
* 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
/**
* 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
+ * @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
* 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;
/**
- * 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.
- *
- * Uses the simplified key generation of Jonathan Katz, Yehuda Lindell,
- * "Introduction to Modern Cryptography: Principles and Protocols".
- *
- * @param n n-component of public key
- * @param lambda lambda-component of private key
- * @param mu mu-componenent of private key
- */
static void
-paillier_create (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");
- 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);
- // 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);
+ GNUNET_CONTAINER_DLL_remove (decrypt_sessions_head, decrypt_sessions_tail, ds);
+
+ if (NULL != ds->client_mq)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying decrypt MQ\n");
+ GNUNET_MQ_destroy (ds->client_mq);
+ ds->client_mq = NULL;
+ }
+
+ if (NULL != ds->client)
+ {
+ GNUNET_SERVER_client_disconnect (ds->client);
+ ds->client = NULL;
+ }
+
+ GNUNET_free (ds);
}
-/**
- * Encrypt a value using Paillier's scheme.
- *
- * @param c resulting ciphertext
- * @param m plaintext to encrypt
- * @param n n-component of public key
- */
static void
-paillier_encrypt (gcry_mpi_t c, gcry_mpi_t m, gcry_mpi_t n)
+keygen_session_destroy (struct KeygenSession *ks)
{
- gcry_mpi_t n_square;
- gcry_mpi_t r;
- gcry_mpi_t g;
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying keygen session\n");
- GNUNET_assert (0 != (n_square = gcry_mpi_new (0)));
- GNUNET_assert (0 != (r = gcry_mpi_new (0)));
- GNUNET_assert (0 != (g = gcry_mpi_new (0)));
+ GNUNET_CONTAINER_DLL_remove (keygen_sessions_head, keygen_sessions_tail, ks);
- gcry_mpi_add_ui (g, n, 1);
-
- gcry_mpi_mul (n_square, n, n);
-
- // generate r < n
- do
+ if (NULL != ks->client_mq)
{
- gcry_mpi_randomize (r, PAILLIER_BITS, GCRY_WEAK_RANDOM);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "destroying keygen MQ\n");
+ GNUNET_MQ_destroy (ks->client_mq);
+ ks->client_mq = 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);
-}
+ if (NULL != ks->client)
+ {
+ GNUNET_SERVER_client_disconnect (ks->client);
+ ks->client = NULL;
+ }
-/**
- * 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)
-{
- 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_free (ks);
}
static void
cleanup_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
- /* FIXME: do clean up here */
+ while (NULL != decrypt_sessions_head)
+ decrypt_session_destroy (decrypt_sessions_head);
+
+ while (NULL != keygen_sessions_head)
+ keygen_session_destroy (keygen_sessions_head);
}
+
/**
* Generate the random coefficients of our pre-secret polynomial
*
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 (GNUNET_SECRETSHARING_KEY_BITS);
- GNUNET_assert (0 != ks->presecret_polynomial[i]);
- gcry_mpi_randomize (ks->presecret_polynomial[i], GNUNET_SECRETSHARING_KEY_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,
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_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 (GNUNET_SECRETSHARING_KEY_BITS)));
- GNUNET_assert (0 != (h = gcry_mpi_new (GNUNET_SECRETSHARING_KEY_BITS)));
-
- // multiplicative identity
- gcry_mpi_set_ui (s, 1);
-
share = GNUNET_new (struct GNUNET_SECRETSHARING_Share);
share->num_peers = 0;
share->num_peers++;
share->peers = GNUNET_new_array (share->num_peers, struct GNUNET_PeerIdentity);
- share->hom_share_commitments =
+ 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;
}
}
- print_mpi_fixed (&share->my_share, s, GNUNET_SECRETSHARING_KEY_BITS / 8);
- print_mpi_fixed (&share->public_key, h, GNUNET_SECRETSHARING_KEY_BITS / 8);
+ 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_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);
+
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO, "keygen completed with %u peers\n", share->num_peers);
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "keygen successful with %u peers\n", share->num_peers);
+ /* Write the share. If 0 peers completed the dkg, an empty
+ * share will be sent. */
m = GNUNET_malloc (sizeof (struct GNUNET_SECRETSHARING_SecretReadyMessage) +
ks->num_peers * sizeof (struct GNUNET_PeerIdentity));
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);
* (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
*/
unsigned int i;
gcry_mpi_t idx;
gcry_mpi_t v;
+ gcry_mpi_t c;
- GNUNET_assert (0 != (v = gcry_mpi_new (GNUNET_SECRETSHARING_KEY_BITS)));
- GNUNET_assert (0 != (idx = gcry_mpi_new (GNUNET_SECRETSHARING_KEY_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)));
+ GNUNET_assert (NULL != (c = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
element_size = (sizeof (struct GNUNET_SECRETSHARING_KeygenRevealData) +
- 2 * GNUNET_SECRETSHARING_KEY_BITS / 8 * ks->num_peers +
- 1 * GNUNET_SECRETSHARING_KEY_BITS / 8 * ks->threshold);
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->num_peers +
+ sizeof (struct GNUNET_CRYPTO_PaillierCiphertext) * 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;
{
ptrdiff_t remaining = last_pos - pos;
GNUNET_assert (remaining > 0);
- gcry_mpi_set_ui (idx, i);
+ gcry_mpi_set_ui (idx, i + 1);
// evaluate the polynomial
- horner_eval (v, ks->presecret_polynomial, ks->threshold, idx, elgamal_p);
+ horner_eval (v, ks->presecret_polynomial, ks->threshold, idx, elgamal_q);
// take g to the result
gcry_mpi_powm (v, elgamal_g, v, elgamal_p);
- print_mpi_fixed (pos, v, GNUNET_SECRETSHARING_KEY_BITS / 8);
- pos += GNUNET_SECRETSHARING_KEY_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 preshares\n",
+ ks->local_peer_idx);
+
// encrypted pre-shares
for (i = 0; i < ks->num_peers; i++)
{
ptrdiff_t remaining = last_pos - pos;
+ struct GNUNET_CRYPTO_PaillierCiphertext *ciphertext;
+
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_n);
- print_mpi_fixed (pos, v, GNUNET_SECRETSHARING_KEY_BITS / 8);
- pos += GNUNET_SECRETSHARING_KEY_BITS / 8;
+ ciphertext = (void *) pos;
+ memset (ciphertext, 0, sizeof *ciphertext);
+ 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
+ GNUNET_CRYPTO_paillier_encrypt (&ks->info[i].paillier_public_key, v, 0, ciphertext);
+ }
+ pos += sizeof *ciphertext;
}
+ 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);
- print_mpi_fixed (pos, v, GNUNET_SECRETSHARING_KEY_BITS / 8);
- pos += GNUNET_SECRETSHARING_KEY_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);
}
+static gcry_mpi_t
+keygen_reveal_get_exp_preshare (struct KeygenSession *ks,
+ const struct GNUNET_SECRETSHARING_KeygenRevealData *d,
+ unsigned int idx)
+{
+ unsigned char *pos;
+ gcry_mpi_t exp_preshare;
+
+ GNUNET_assert (idx < ks->num_peers);
+
+ GNUNET_assert (NULL != (exp_preshare = gcry_mpi_new (0)));
+
+ pos = (void *) &d[1];
+ // skip exponentiated pre-shares we don't want
+ pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * idx;
+ GNUNET_CRYPTO_mpi_scan_unsigned (&exp_preshare, pos, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
+ return exp_preshare;
+}
+
+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);
+ GNUNET_assert (NULL != (exp_coeff = gcry_mpi_new (0)));
+
+ pos = (void *) &d[1];
+ // skip exponentiated pre-shares
+ pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->num_peers;
+ // skip encrypted pre-shares
+ pos += sizeof (struct GNUNET_CRYPTO_PaillierCiphertext) * 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_CRYPTO_PaillierCiphertext *
+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 exponentiated pre-shares
+ pos += GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->num_peers;
+ // skip encrypted pre-shares we're not interested in
+ pos += sizeof (struct GNUNET_CRYPTO_PaillierCiphertext) * idx;
+ return (struct GNUNET_CRYPTO_PaillierCiphertext *) pos;
+}
+
+
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;
+ 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 * GNUNET_SECRETSHARING_KEY_BITS / 8 * ks->num_peers +
- 1 * GNUNET_SECRETSHARING_KEY_BITS / 8 * ks->threshold);
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->num_peers +
+ sizeof (struct GNUNET_CRYPTO_PaillierCiphertext) * ks->num_peers +
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8 * ks->threshold);
if (element->size != expected_element_size)
{
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 += GNUNET_SECRETSHARING_KEY_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, GNUNET_SECRETSHARING_KEY_BITS / 8, NULL));
-
- pos = (void *) &d[1];
- // skip exp. pre-shares
- pos += GNUNET_SECRETSHARING_KEY_BITS / 8 * ks->num_peers;
- // skip to the encrypted value for our peer
- pos += PAILLIER_BITS / 8 * ks->local_peer_idx;
+ 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;
+ }
- GNUNET_assert (0 == gcry_mpi_scan (&c, GCRYMPI_FMT_USG,
- pos, PAILLIER_BITS / 8, NULL));
+ 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 != (info->decrypted_preshare = mpi_new (0)));
+ 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);
- paillier_decrypt (info->decrypted_preshare, c, ks->paillier_lambda, ks->paillier_mu,
- ks->info[ks->local_peer_idx].paillier_n);
+ 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,
+ keygen_reveal_get_enc_preshare (ks, d, ks->local_peer_idx),
+ 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)))
+ // TODO: restore a valid secret from the decryption (the hard part, solving SVP with gauss)
+ if (0 != gcry_mpi_cmp (tmp, info->preshare_commitment))
{
- 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_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;
+ gcry_mpi_t tmp;
+ 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_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);
+ }
+ exp_preshare = keygen_reveal_get_exp_preshare (ks, d, j);
+ gcry_mpi_mod (exp_preshare, exp_preshare, elgamal_p);
+ if (0 != gcry_mpi_cmp (prod, exp_preshare))
+ {
+ 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)
info->round2_valid = GNUNET_YES;
}
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[GNUNET_SECRETSHARING_KEY_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 (GNUNET_SECRETSHARING_KEY_BITS)));
+ GNUNET_assert (0 != (v = gcry_mpi_new (GNUNET_SECRETSHARING_ELGAMAL_BITS)));
gcry_mpi_powm (v, elgamal_g, ks->presecret_polynomial[0], elgamal_p);
- print_mpi_fixed (v_data, v, GNUNET_SECRETSHARING_KEY_BITS);
+ GNUNET_CRYPTO_mpi_print_unsigned (v_data, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, v);
- GNUNET_CRYPTO_hash (v_data, GNUNET_SECRETSHARING_KEY_BITS / 8, &d->commitment);
+ GNUNET_CRYPTO_hash (v_data, GNUNET_SECRETSHARING_ELGAMAL_BITS / 8, &d->commitment);
- print_mpi_fixed (d->pubkey.n, ks->info[ks->local_peer_idx].paillier_n,
- PAILLIER_BITS / 8);
+ 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_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++)
ks->info[i].peer = ks->peers[i];
- 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_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_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;
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++)
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,
- GNUNET_SECRETSHARING_KEY_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_mpi_fixed (&msg->plaintext, m, GNUNET_SECRETSHARING_KEY_BITS / 8);
+ 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_log (GNUNET_ERROR_TYPE_INFO, "sent decrypt done to client\n");
+
// 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)
{
return;
}
- // FIXME: check NIZP first
+ 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;
+ }
+
+
+ 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, info - session->info, tmp1_str, tmp2_str);
+ GNUNET_free (tmp1_str);
+ GNUNET_free (tmp2_str);
+ // return;
+ }
+
+
+ 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, info - session->info);
+ // return;
+ }
+
- GNUNET_assert (0 == gcry_mpi_scan (&info->partial_decryption,
- GCRYMPI_FMT_USG, &d->partial_decryption, GNUNET_SECRETSHARING_KEY_BITS / 8, NULL));
+ GNUNET_CRYPTO_mpi_scan_unsigned (&info->partial_decryption, &d->partial_decryption,
+ GNUNET_SECRETSHARING_ELGAMAL_BITS / 8);
}
+
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;
+
+ /* 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)));
- GNUNET_assert (0 == gcry_mpi_scan (&x, GCRYMPI_FMT_USG, ds->ciphertext.c1_bits, GNUNET_SECRETSHARING_KEY_BITS / 8, NULL));
- GNUNET_assert (0 == gcry_mpi_scan (&s, GCRYMPI_FMT_USG, &ds->share->my_share, GNUNET_SECRETSHARING_KEY_BITS / 8, NULL));
+ // 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.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_mpi_fixed (&d.partial_decryption, x, GNUNET_SECRETSHARING_KEY_BITS / 8);
-
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);
}
(const void *) message;
struct DecryptSession *ds;
struct GNUNET_HashCode session_id;
+ unsigned int i;
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);
+ ds->start = GNUNET_TIME_absolute_ntoh (msg->start);
ds->deadline = GNUNET_TIME_absolute_ntoh (msg->deadline);
ds->ciphertext = msg->ciphertext;
ds->share->num_peers,
ds->share->peers,
&session_id,
- decrypt_new_element,
+ ds->start,
+ ds->deadline,
+ &decrypt_new_element,
ds);
+
+ ds->info = GNUNET_new_array (ds->share->num_peers, struct DecryptPeerInfo);
+ for (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, ds->deadline, decrypt_conclude, ds);
+ GNUNET_CONSENSUS_conclude (ds->consensus, decrypt_conclude, ds);
+
+ GNUNET_SERVER_receive_done (client, GNUNET_OK);
+
+ 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));
+}
+
+
+static struct KeygenSession *
+keygen_session_get (struct GNUNET_SERVER_Client *client)
+{
+ struct KeygenSession *ks;
+ for (ks = keygen_sessions_head; NULL != ks; ks = ks->next)
+ if (ks->client == client)
+ return ks;
+ return NULL;
+}
+
+static struct DecryptSession *
+decrypt_session_get (struct GNUNET_SERVER_Client *client)
+{
+ struct DecryptSession *ds;
+ for (ds = decrypt_sessions_head; NULL != ds; ds = ds->next)
+ if (ds->client == client)
+ return ds;
+ return NULL;
+}
+
+
+/**
+ * Clean up after a client has disconnected
+ *
+ * @param cls closure, unused
+ * @param client the client to clean up after
+ */
+static void
+handle_client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
+{
+ struct KeygenSession *ks;
+ struct DecryptSession *ds;
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "handling client disconnect\n");
+
+ ks = keygen_session_get (client);
+ if (NULL != ks)
+ keygen_session_destroy (ks);
+
+ ds = decrypt_session_get (client);
+ if (NULL != ds)
+ decrypt_session_destroy (ds);
}
return;
}
GNUNET_SERVER_add_handlers (server, handlers);
+ GNUNET_SERVER_disconnect_notify (server, &handle_client_disconnect, NULL);
GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleanup_task,
NULL);
}
projects / oweals / gnunet.git / blobdiff