major random stuff

1 files changed, 440 insertions, 137 deletions

diff --git a/crypto.c b/crypto.c
index 9c2e272..3140ec6 100644
--- a/crypto.c
+++ b/crypto.c
@@ -20,6 +20,7 @@
  * @author Markus Teich
  */
 
+#include "brandt_config.h"
 
 #include <arpa/inet.h>
 #include <gcrypt.h>
@@ -61,17 +62,22 @@ static gcry_ctx_t       ec_ctx;
 static gcry_mpi_point_t ec_gen;
 static gcry_mpi_point_t ec_zero;
 static gcry_mpi_t       ec_n;
+static GNUNET_CRYPTO_EccDlogContext *ec_dlogctx;
 
 
 /**
  * brandt_crypto_init initializes the crypto system and must be called before
  * any other function from this file.
+ * 
+ * @param[in] dlogctx Pointer to the prepared dlog context.
  */
 void
-brandt_crypto_init ()
+brandt_crypto_init (GNUNET_CRYPTO_EccDlogContext *dlogctx)
 {
 	gcry_error_t rc;
 
+	ec_dlogctx = dlogctx;
+
 	rc = gcry_mpi_ec_new (&ec_ctx, NULL, CURVE);
 	brandt_assert_gpgerr (rc);
 
@@ -159,7 +165,7 @@ ec_keypair_create (gcry_mpi_point_t pkey, gcry_mpi_t skey)
 	gcry_mpi_t sk;
 
 	brandt_assert (NULL != pkey);
-	sk = (NULL == skey) ? gcry_mpi_new (0) : skey;
+	sk = (NULL == skey) ? gcry_mpi_new (256) : skey;
 
 	ec_skey_create (sk);
 	gcry_mpi_ec_mul (pkey, sk, ec_gen, ec_ctx);
@@ -191,6 +197,25 @@ ec_keypair_create_base (gcry_mpi_point_t       pkey,
 
 
 /**
+ * ec_point_copy creates a copy of one curve point
+ *
+ * @param[out] dst where to store the copy
+ * @param[in] src the input point to be copied
+ */
+void
+ec_point_copy (gcry_mpi_point_t dst, const gcry_mpi_point_t src)
+{
+	gcry_mpi_t x = gcry_mpi_new (256);
+	gcry_mpi_t y = gcry_mpi_new (256);
+	gcry_mpi_t z = gcry_mpi_new (256);
+
+	brandt_assert (dst && src);
+	gcry_mpi_point_get (x, y, z, src);
+	gcry_mpi_point_snatch_set (dst, x, y, z);
+}
+
+
+/**
  * ec_point_cmp compares two curve points
  *
  * @param[in] a the first point
@@ -202,10 +227,10 @@ int
 ec_point_cmp (const gcry_mpi_point_t a, const gcry_mpi_point_t b)
 {
 	int        ret = 1;
-	gcry_mpi_t ax = gcry_mpi_new (0);
-	gcry_mpi_t bx = gcry_mpi_new (0);
-	gcry_mpi_t ay = gcry_mpi_new (0);
-	gcry_mpi_t by = gcry_mpi_new (0);
+	gcry_mpi_t ax = gcry_mpi_new (256);
+	gcry_mpi_t bx = gcry_mpi_new (256);
+	gcry_mpi_t ay = gcry_mpi_new (256);
+	gcry_mpi_t by = gcry_mpi_new (256);
 
 	brandt_assert (a && b);
 	if (!ax || !bx || !ay || !by)
@@ -592,8 +617,7 @@ smc_sum (gcry_mpi_point_t out,
          uint16_t         step)
 {
 	brandt_assert (NULL != out);
-	/**\todo: how to copy a point more efficiently? */
-	gcry_mpi_ec_add (out, ec_zero, ec_zero, ec_ctx);
+	ec_point_copy (out, ec_zero);
 	for (uint16_t i = 0; i < len * step; i += step)
 		gcry_mpi_ec_add (out, out, in[i], ec_ctx);
 }
@@ -603,12 +627,12 @@ smc_sum (gcry_mpi_point_t out,
  * smc_gen_keyshare creates the private additive keyshare and computes the
  * public multiplicative key share
  *
- * @param[in,out] ad Pointer to the AuctionData struct to operate on
+ * @param[in,out] ad Pointer to the BRANDT_Auction struct to operate on
  * @param[out] buflen \todo
  * @return \todo
  */
 unsigned char *
-smc_gen_keyshare (struct AuctionData *ad, size_t *buflen)
+smc_gen_keyshare (struct BRANDT_Auction *ad, size_t *buflen)
 {
 	unsigned char   *ret;
 	struct proof_dl *proof1;
@@ -624,7 +648,7 @@ smc_gen_keyshare (struct AuctionData *ad, size_t *buflen)
 
 	proof1 = (struct proof_dl *)(ret + sizeof (struct ec_mpi));
 
-	ad->x = gcry_mpi_new (0);
+	ad->x = gcry_mpi_new (256);
 	ec_skey_create (ad->x);
 	smc_zkp_dl (ad->y[ad->i], ad->x, proof1);
 	ec_point_serialize ((struct ec_mpi *)ret, ad->y[ad->i]);
@@ -633,8 +657,8 @@ smc_gen_keyshare (struct AuctionData *ad, size_t *buflen)
 
 
 int
-smc_recv_keyshare (struct AuctionData *ad,
-                   unsigned char      *buf,
+smc_recv_keyshare (struct BRANDT_Auction *ad,
+                   const unsigned char      *buf,
                    size_t             buflen,
                    uint16_t           sender)
 {
@@ -658,8 +682,7 @@ smc_recv_keyshare (struct AuctionData *ad,
 		goto quit;
 	}
 
-	/**\todo: how to copy a point more efficiently? */
-	gcry_mpi_ec_add (ad->y[sender], ec_zero, y, ec_ctx);
+	ec_point_copy (ad->y[sender], y);
 
 	ret = 1;
 quit:
@@ -675,7 +698,7 @@ quit:
  * @param buflen TODO
  */
 unsigned char *
-smc_encrypt_bid (struct AuctionData *ad, size_t *buflen)
+smc_encrypt_bid (struct BRANDT_Auction *ad, size_t *buflen)
 {
 	unsigned char    *ret;
 	unsigned char    *cur;
@@ -699,8 +722,8 @@ smc_encrypt_bid (struct AuctionData *ad, size_t *buflen)
 	ad->Y = gcry_mpi_point_new (0);
 	smc_sum (ad->Y, ad->y, ad->n, 1);
 
-	r_sum = gcry_mpi_new (0);
-	r_part = gcry_mpi_new (0);
+	r_sum = gcry_mpi_new (256);
+	r_part = gcry_mpi_new (256);
 
 	for (uint16_t j = 0; j < ad->k; j++)
 	{
@@ -726,13 +749,13 @@ smc_encrypt_bid (struct AuctionData *ad, size_t *buflen)
 
 
 int
-smc_recv_encrypted_bid (struct AuctionData *ad,
-                        unsigned char      *buf,
+smc_recv_encrypted_bid (struct BRANDT_Auction *ad,
+                        const unsigned char      *buf,
                         size_t             buflen,
                         uint16_t           sender)
 {
 	int              ret = 0;
-	unsigned char    *cur = buf;
+	const unsigned char    *cur = buf;
 	struct proof_0og *proof3;
 	gcry_mpi_point_t **ct; /* ciphertexts */
 	gcry_mpi_point_t alpha_sum = gcry_mpi_point_new (0);
@@ -748,8 +771,8 @@ smc_recv_encrypted_bid (struct AuctionData *ad,
 		goto quit;
 	}
 
-	gcry_mpi_ec_mul (alpha_sum, GCRYMPI_CONST_ONE, ec_zero, ec_ctx);
-	gcry_mpi_ec_mul (beta_sum, GCRYMPI_CONST_ONE, ec_zero, ec_ctx);
+	ec_point_copy (alpha_sum, ec_zero);
+	ec_point_copy (beta_sum, ec_zero);
 
 	for (uint16_t j = 0; j < ad->k; j++)
 	{
@@ -779,9 +802,8 @@ smc_recv_encrypted_bid (struct AuctionData *ad,
 
 	for (uint16_t j = 0; j < ad->k; j++)
 	{
-		/**\todo: how to copy a point more efficiently? */
-		gcry_mpi_ec_add (ad->alpha[sender][j], ec_zero, ct[0][j], ec_ctx);
-		gcry_mpi_ec_add (ad->beta[sender][j], ec_zero, ct[1][j], ec_ctx);
+		ec_point_copy (ad->alpha[sender][j], ct[0][j]);
+		ec_point_copy (ad->beta[sender][j], ct[1][j]);
 	}
 	smc_free2 (ct, 2, ad->k);
 
@@ -794,13 +816,345 @@ quit:
 
 
 /**
- * smc_compute_outcome \todo
+ * fp_pub_compute_outcome \todo
+ *
+ * @param ad TODO
+ * @param buflen TODO
+ */
+unsigned char *
+fp_pub_compute_outcome (struct BRANDT_Auction *ad, size_t *buflen)
+{
+	unsigned char     *ret;
+	unsigned char     *cur;
+	gcry_mpi_t        coeff = gcry_mpi_copy (GCRYMPI_CONST_ONE);
+	gcry_mpi_point_t  tmp = gcry_mpi_point_new (0);
+	gcry_mpi_point_t  *tlta1;
+	gcry_mpi_point_t  *tltb1;
+	gcry_mpi_point_t  **tlta2;
+	gcry_mpi_point_t  **tltb2;
+	struct ec_mpi     *gamma;
+	struct ec_mpi     *delta;
+	struct proof_2dle *proof2;
+
+	brandt_assert (ad && buflen);
+
+	*buflen = (ad->k * (sizeof (*gamma) + sizeof (*delta) + sizeof (*proof2)));
+	if (NULL == (cur = (ret = calloc (1, *buflen))) ||
+	    NULL == (ad->gamma2 = smc_init2 (ad->n, ad->k)) ||
+	    NULL == (ad->delta2 = smc_init2 (ad->n, ad->k)) ||
+	    NULL == (ad->tmpa1 = smc_init1 (ad->k)) ||
+	    NULL == (ad->tmpb1 = smc_init1 (ad->k)))
+	{
+		weprintf ("unable to alloc memory for first price outcome computation");
+		return NULL;
+	}
+
+	/* create temporary lookup tables with partial sums */
+	tlta1 = smc_init1 (ad->k);
+	tltb1 = smc_init1 (ad->k);
+	tlta2 = smc_init2 (ad->n, ad->k);
+	tltb2 = smc_init2 (ad->n, ad->k);
+
+	/* temporary lookup table for sum of bid vectors */
+	for (uint16_t i = 0; i < ad->n; i++)
+	{
+		smc_sums_partial (tlta2[i], ad->alpha[i], ad->k, 1, 1);
+		smc_sums_partial (tltb2[i], ad->beta[i], ad->k, 1, 1);
+		for (uint16_t j = 0; j < ad->k; j++)
+		{
+			gcry_mpi_ec_sub (tlta2[i][j],
+			                 tlta2[i][ad->k - 1],
+			                 tlta2[i][j],
+			                 ec_ctx);
+			gcry_mpi_ec_sub (tltb2[i][j],
+			                 tltb2[i][ad->k - 1],
+			                 tltb2[i][j],
+			                 ec_ctx);
+		}
+		brandt_assert (!ec_point_cmp (ec_zero, tlta2[i][ad->k - 1]));
+		brandt_assert (!ec_point_cmp (ec_zero, tltb2[i][ad->k - 1]));
+	}
+	for (uint16_t j = 0; j < ad->k; j++)
+	{
+		smc_sum (tlta1[j], &tlta2[0][j], ad->n, ad->k);
+		smc_sum (tltb1[j], &tltb2[0][j], ad->n, ad->k);
+	}
+	smc_free2 (tlta2, ad->n, ad->k);
+	smc_free2 (tltb2, ad->n, ad->k);
+	brandt_assert (!ec_point_cmp (ec_zero, tlta1[ad->k - 1]));
+	brandt_assert (!ec_point_cmp (ec_zero, tltb1[ad->k - 1]));
+
+	/* temporarily store the \sum_{i=1}^n2^{i-1}b_i in tmp1, since it is needed
+	 * each time a gamma,delta pair is received from another bidder */
+	for (uint16_t i = 0; i < ad->n; i++)
+	{
+		for (uint16_t j = 0; j < ad->k; j++)
+		{
+			gcry_mpi_ec_mul (tmp, coeff, ad->alpha[i][j], ec_ctx);
+			gcry_mpi_ec_add (ad->tmpa1[j], ad->tmpa1[j], tmp, ec_ctx);
+			gcry_mpi_ec_mul (tmp, coeff, ad->beta[i][j], ec_ctx);
+			gcry_mpi_ec_add (ad->tmpb1[j], ad->tmpb1[j], tmp, ec_ctx);
+		}
+		gcry_mpi_mul_ui (coeff, coeff, 2);
+	}
+
+	for (uint16_t j = 0; j < ad->k; j++)
+	{
+		gamma = (struct ec_mpi *)cur;
+		delta = &((struct ec_mpi *)cur)[1];
+		proof2 = (struct proof_2dle *)(cur + 2 * sizeof (struct ec_mpi));
+
+		/* copy unmasked outcome to all other bidder layers so they don't
+		 * have to be recomputed to check the ZK proof_2dle's from other
+		 * bidders when receiving their outcome messages */
+		for (uint16_t a = 0; a < ad->n; a++)
+		{
+			ec_point_copy (ad->gamma2[a][j], tlta1[j]);
+			ec_point_copy (ad->delta2[a][j], tltb1[j]);
+		}
+
+		/* apply random masking for losing bidders */
+		smc_zkp_2dle (ad->gamma2[ad->i][j],
+		              ad->delta2[ad->i][j],
+		              tlta1[j],
+		              tltb1[j],
+		              NULL,
+		              proof2);
+
+		ec_point_serialize (gamma, ad->gamma2[ad->i][j]);
+		ec_point_serialize (delta, ad->delta2[ad->i][j]);
+
+		/* add winner determination for own gamma,delta */
+		gcry_mpi_ec_add (ad->gamma2[ad->i][j],
+		                 ad->gamma2[ad->i][j],
+		                 ad->tmpa1[j],
+		                 ec_ctx);
+		gcry_mpi_ec_add (ad->delta2[ad->i][j],
+		                 ad->delta2[ad->i][j],
+		                 ad->tmpb1[j],
+		                 ec_ctx);
+
+		cur += sizeof (*gamma) + sizeof (*delta) + sizeof (*proof2);
+	}
+
+	gcry_mpi_release (coeff);
+	gcry_mpi_point_release (tmp);
+	smc_free1 (tlta1, ad->k);
+	smc_free1 (tltb1, ad->k);
+	return ret;
+}
+
+
+int
+fp_pub_recv_outcome (struct BRANDT_Auction *ad,
+                     const unsigned char      *buf,
+                     size_t             buflen,
+                     uint16_t           sender)
+{
+	int               ret = 0;
+	const unsigned char     *cur = buf;
+	struct proof_2dle *proof2;
+	gcry_mpi_point_t  gamma = gcry_mpi_point_new (0);
+	gcry_mpi_point_t  delta = gcry_mpi_point_new (0);
+
+	brandt_assert (ad && buf);
+
+	if (buflen != (ad->k * (2 * sizeof (struct ec_mpi) + sizeof (*proof2))))
+	{
+		weprintf ("wrong size of received outcome");
+		goto quit;
+	}
+
+	for (uint16_t j = 0; j < ad->k; j++)
+	{
+		ec_point_parse (gamma, (struct ec_mpi *)cur);
+		ec_point_parse (delta, &((struct ec_mpi *)cur)[1]);
+		proof2 = (struct proof_2dle *)(cur + 2 * sizeof (struct ec_mpi));
+		if (smc_zkp_2dle_check (gamma,
+		                        delta,
+		                        ad->gamma2[sender][j],
+		                        ad->delta2[sender][j],
+		                        proof2))
+		{
+			weprintf ("wrong zkp2 for gamma, delta received");
+			goto quit;
+		}
+		ec_point_copy (ad->gamma2[sender][j], gamma);
+		ec_point_copy (ad->delta2[sender][j], delta);
+
+		/* add winner determination summand */
+		gcry_mpi_ec_add (ad->gamma2[sender][j],
+		                 ad->gamma2[sender][j],
+		                 ad->tmpa1[j],
+		                 ec_ctx);
+		gcry_mpi_ec_add (ad->delta2[sender][j],
+		                 ad->delta2[sender][j],
+		                 ad->tmpb1[j],
+		                 ec_ctx);
+
+		cur += 2 * sizeof (struct ec_mpi) + sizeof (*proof2);
+	}
+
+	ret = 1;
+quit:
+	gcry_mpi_point_release (gamma);
+	gcry_mpi_point_release (delta);
+	return ret;
+}
+
+
+/**
+ * fp_pub_decrypt_outcome \todo
+ *
+ * @param ad TODO
+ * @param buflen TODO
+ */
+unsigned char *
+fp_pub_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen)
+{
+	unsigned char     *ret;
+	unsigned char     *cur;
+	gcry_mpi_point_t  tmp = gcry_mpi_point_new (0);
+	struct ec_mpi     *phi;
+	struct proof_2dle *proof2;
+
+	brandt_assert (ad && buflen);
+
+	*buflen = (ad->k * (sizeof (*phi) + sizeof (*proof2)));
+	if (NULL == (cur = (ret = calloc (1, *buflen))) ||
+	    NULL == (ad->phi2 = smc_init2 (ad->n, ad->k)))
+	{
+		weprintf ("unable to alloc memory for first price outcome decryption");
+		return NULL;
+	}
+
+	for (uint16_t j = 0; j < ad->k; j++)
+	{
+		phi = (struct ec_mpi *)cur;
+		proof2 = (struct proof_2dle *)(cur + sizeof (*phi));
+
+		smc_sum (tmp, &ad->delta2[0][j], ad->n, ad->n * ad->k);
+
+		/* copy still encrypted outcome to all other bidder layers so they
+		 * don't have to be recomputed to check the ZK proof_2dle's from
+		 * other bidders when receiving their outcome decryption messages */
+		for (uint16_t a = 0; a < ad->n; a++)
+			ec_point_copy (ad->phi2[a][j], tmp);
+
+		/* decrypt outcome component and prove the correct key was used */
+		smc_zkp_2dle (ad->phi2[ad->i][j],
+		              NULL,
+		              tmp,
+		              ec_gen,
+		              ad->x,
+		              proof2);
+
+		ec_point_serialize (phi, ad->phi2[ad->i][j]);
+
+		cur += sizeof (*phi) + sizeof (*proof2);
+	}
+
+	gcry_mpi_point_release (tmp);
+	return ret;
+}
+
+
+int
+fp_pub_recv_decryption (struct BRANDT_Auction *ad,
+                        const unsigned char      *buf,
+                        size_t             buflen,
+                        uint16_t           sender)
+{
+	int               ret = 0;
+	const unsigned char     *cur = buf;
+	struct proof_2dle *proof2;
+	gcry_mpi_point_t  phi = gcry_mpi_point_new (0);
+
+	brandt_assert (ad && buf);
+
+	if (buflen != (ad->k * (sizeof (struct ec_mpi) + sizeof (*proof2))))
+	{
+		weprintf ("wrong size of received outcome decryption");
+		goto quit;
+	}
+
+	for (uint16_t j = 0; j < ad->k; j++)
+	{
+		ec_point_parse (phi, (struct ec_mpi *)cur);
+		proof2 = (struct proof_2dle *)(cur + sizeof (struct ec_mpi));
+		if (smc_zkp_2dle_check (phi,
+		                        ad->y[sender],
+		                        ad->phi2[sender][j],
+		                        ec_gen,
+		                        proof2))
+		{
+			weprintf ("wrong zkp2 for phi, y received");
+			goto quit;
+		}
+		ec_point_copy (ad->phi2[sender][j], phi);
+		cur += sizeof (struct ec_mpi) + sizeof (*proof2);
+	}
+
+	ret = 1;
+quit:
+	gcry_mpi_point_release (phi);
+	return ret;
+}
+
+
+int32_t
+fp_pub_determine_outcome (struct BRANDT_Auction *ad, uint16_t *winner)
+{
+	int32_t          ret = -1;
+	int              dlogi = -1;
+	gcry_mpi_t       dlog = gcry_mpi_new (256);
+	gcry_mpi_point_t sum_gamma = gcry_mpi_point_new (0);
+	gcry_mpi_point_t sum_phi = gcry_mpi_point_new (0);
+
+	brandt_assert (ad);
+
+	for (uint16_t j = ad->k - 1; j >= 0; j--)
+	{
+		smc_sum (sum_gamma, &ad->gamma2[0][j], ad->n, ad->k);
+		smc_sum (sum_phi, &ad->phi2[0][j], ad->n, ad->k);
+		gcry_mpi_ec_sub (sum_gamma, sum_gamma, sum_phi, ec_ctx);
+		/* first non-zero component determines the price */
+		if (ec_point_cmp (sum_gamma, ec_zero))
+		{
+			ret = j;
+			break;
+		}
+	}
+
+	dlogi = GNUNET_CRYPTO_ecc_dlog (ec_dlogctx, sum_gamma);
+	brandt_assert (dlogi > 0);
+	gcry_mpi_set_ui (dlog, (unsigned long)dlogi);
+
+	for (uint16_t i = 0; i < ad->n; i++)
+	{
+		if (gcry_mpi_test_bit (dlog, i))
+		{
+			if (winner)
+				winner = i;
+			break;
+		}
+	}
+
+	gcry_mpi_release (dlog);
+	gcry_mpi_point_release (sum_gamma);
+	gcry_mpi_point_release (sum_phi);
+	return ret;
+}
+
+
+/**
+ * fp_priv_compute_outcome \todo
  *
  * @param ad TODO
  * @param buflen TODO
  */
 unsigned char *
-smc_compute_outcome (struct AuctionData *ad, size_t *buflen)
+fp_priv_compute_outcome (struct BRANDT_Auction *ad, size_t *buflen)
 {
 	unsigned char     *ret;
 	unsigned char     *cur;
@@ -821,8 +1175,8 @@ smc_compute_outcome (struct AuctionData *ad, size_t *buflen)
 	*buflen = (ad->n * ad->k *                 /* nk * (gamma, delta, proof2) */
 	           (sizeof (*gamma) + sizeof (*delta) + sizeof (*proof2)));
 	if (NULL == (cur = (ret = calloc (1, *buflen))) ||
-	    NULL == (ad->gamma = smc_init3 (ad->n, ad->n, ad->k)) ||
-	    NULL == (ad->delta = smc_init3 (ad->n, ad->n, ad->k)))
+	    NULL == (ad->gamma3 = smc_init3 (ad->n, ad->n, ad->k)) ||
+	    NULL == (ad->delta3 = smc_init3 (ad->n, ad->n, ad->k)))
 	{
 		weprintf ("unable to alloc memory for first price outcome computation");
 		return NULL;
@@ -912,21 +1266,20 @@ smc_compute_outcome (struct AuctionData *ad, size_t *buflen)
 			 * bidders when receiving their outcome messages */
 			for (uint16_t a = 0; a < ad->n; a++)
 			{
-				/**\todo: how to copy a point more efficiently? */
-				gcry_mpi_ec_add (ad->gamma[a][i][j], ec_zero, tmpa, ec_ctx);
-				gcry_mpi_ec_add (ad->delta[a][i][j], ec_zero, tmpb, ec_ctx);
+				ec_point_copy (ad->gamma3[a][i][j], tmpa);
+				ec_point_copy (ad->delta3[a][i][j], tmpb);
 			}
 
 			/* apply random masking for losing bidders */
-			smc_zkp_2dle (ad->gamma[ad->i][i][j],
-			              ad->delta[ad->i][i][j],
+			smc_zkp_2dle (ad->gamma3[ad->i][i][j],
+			              ad->delta3[ad->i][i][j],
 			              tmpa,
 			              tmpb,
 			              NULL,
 			              proof2);
 
-			ec_point_serialize (gamma, ad->gamma[ad->i][i][j]);
-			ec_point_serialize (delta, ad->delta[ad->i][i][j]);
+			ec_point_serialize (gamma, ad->gamma3[ad->i][i][j]);
+			ec_point_serialize (delta, ad->delta3[ad->i][i][j]);
 
 			cur += sizeof (*gamma) + sizeof (*delta) + sizeof (*proof2);
 		}
@@ -945,13 +1298,13 @@ smc_compute_outcome (struct AuctionData *ad, size_t *buflen)
 
 
 int
-smc_recv_outcome (struct AuctionData *ad,
-                  unsigned char      *buf,
-                  size_t             buflen,
-                  uint16_t           sender)
+fp_priv_recv_outcome (struct BRANDT_Auction *ad,
+                      const unsigned char      *buf,
+                      size_t             buflen,
+                      uint16_t           sender)
 {
 	int               ret = 0;
-	unsigned char     *cur = buf;
+	const unsigned char     *cur = buf;
 	struct proof_2dle *proof2;
 	gcry_mpi_point_t  gamma = gcry_mpi_point_new (0);
 	gcry_mpi_point_t  delta = gcry_mpi_point_new (0);
@@ -974,15 +1327,15 @@ smc_recv_outcome (struct AuctionData *ad,
 			proof2 = (struct proof_2dle *)(cur + 2 * sizeof (struct ec_mpi));
 			if (smc_zkp_2dle_check (gamma,
 			                        delta,
-			                        ad->gamma[sender][i][j],
-			                        ad->delta[sender][i][j],
+			                        ad->gamma3[sender][i][j],
+			                        ad->delta3[sender][i][j],
 			                        proof2))
 			{
 				weprintf ("wrong zkp2 for gamma, delta received");
 				goto quit;
 			}
-			gcry_mpi_ec_add (ad->gamma[sender][i][j], gamma, ec_zero, ec_ctx);
-			gcry_mpi_ec_add (ad->delta[sender][i][j], delta, ec_zero, ec_ctx);
+			ec_point_copy (ad->gamma3[sender][i][j], gamma);
+			ec_point_copy (ad->delta3[sender][i][j], delta);
 			cur += 2 * sizeof (struct ec_mpi) + sizeof (*proof2);
 		}
 	}
@@ -996,13 +1349,13 @@ quit:
 
 
 /**
- * smc_decrypt_outcome \todo
+ * fp_priv_decrypt_outcome \todo
  *
  * @param ad TODO
  * @param buflen TODO
  */
 unsigned char *
-smc_decrypt_outcome (struct AuctionData *ad, size_t *buflen)
+fp_priv_decrypt_outcome (struct BRANDT_Auction *ad, size_t *buflen)
 {
 	unsigned char     *ret;
 	unsigned char     *cur;
@@ -1014,7 +1367,7 @@ smc_decrypt_outcome (struct AuctionData *ad, size_t *buflen)
 
 	*buflen = (ad->n * ad->k * (sizeof (*phi) + sizeof (*proof2)));
 	if (NULL == (cur = (ret = calloc (1, *buflen))) ||
-	    NULL == (ad->phi = smc_init3 (ad->n, ad->n, ad->k)))
+	    NULL == (ad->phi3 = smc_init3 (ad->n, ad->n, ad->k)))
 	{
 		weprintf ("unable to alloc memory for first price outcome decryption");
 		return NULL;
@@ -1027,24 +1380,23 @@ smc_decrypt_outcome (struct AuctionData *ad, size_t *buflen)
 			phi = (struct ec_mpi *)cur;
 			proof2 = (struct proof_2dle *)(cur + sizeof (*phi));
 
-			smc_sum (tmp, &ad->delta[0][i][j], ad->n, ad->n * ad->k);
+			smc_sum (tmp, &ad->delta3[0][i][j], ad->n, ad->n * ad->k);
 
 			/* copy still encrypted outcome to all other bidder layers so they
 			 * don't have to be recomputed to check the ZK proof_2dle's from
 			 * other bidders when receiving their outcome decryption messages */
 			for (uint16_t a = 0; a < ad->n; a++)
-				/**\todo: how to copy a point more efficiently? */
-				gcry_mpi_ec_add (ad->phi[a][i][j], ec_zero, tmp, ec_ctx);
+				ec_point_copy (ad->phi3[a][i][j], tmp);
 
 			/* decrypt outcome component and prove the correct key was used */
-			smc_zkp_2dle (ad->phi[ad->i][i][j],
+			smc_zkp_2dle (ad->phi3[ad->i][i][j],
 			              NULL,
 			              tmp,
 			              ec_gen,
 			              ad->x,
 			              proof2);
 
-			ec_point_serialize (phi, ad->phi[ad->i][i][j]);
+			ec_point_serialize (phi, ad->phi3[ad->i][i][j]);
 
 			cur += sizeof (*phi) + sizeof (*proof2);
 		}
@@ -1056,13 +1408,13 @@ smc_decrypt_outcome (struct AuctionData *ad, size_t *buflen)
 
 
 int
-smc_recv_decryption (struct AuctionData *ad,
-                     unsigned char      *buf,
-                     size_t             buflen,
-                     uint16_t           sender)
+fp_priv_recv_decryption (struct BRANDT_Auction *ad,
+                         const unsigned char      *buf,
+                         size_t             buflen,
+                         uint16_t           sender)
 {
 	int               ret = 0;
-	unsigned char     *cur = buf;
+	const unsigned char     *cur = buf;
 	struct proof_2dle *proof2;
 	gcry_mpi_point_t  phi = gcry_mpi_point_new (0);
 
@@ -1082,14 +1434,14 @@ smc_recv_decryption (struct AuctionData *ad,
 			proof2 = (struct proof_2dle *)(cur + sizeof (struct ec_mpi));
 			if (smc_zkp_2dle_check (phi,
 			                        ad->y[sender],
-			                        ad->phi[sender][i][j],
+			                        ad->phi3[sender][i][j],
 			                        ec_gen,
 			                        proof2))
 			{
 				weprintf ("wrong zkp2 for phi, y received");
 				goto quit;
 			}
-			gcry_mpi_ec_add (ad->phi[sender][i][j], phi, ec_zero, ec_ctx);
+			ec_point_copy (ad->phi3[sender][i][j], phi);
 			cur += sizeof (struct ec_mpi) + sizeof (*proof2);
 		}
 	}
@@ -1102,7 +1454,7 @@ quit:
 
 
 int32_t
-smc_determine_outcome (struct AuctionData *ad)
+fp_priv_determine_outcome (struct BRANDT_Auction *ad)
 {
 	int32_t          ret = -1;
 	gcry_mpi_point_t sum_gamma = gcry_mpi_point_new (0);
@@ -1112,8 +1464,8 @@ smc_determine_outcome (struct AuctionData *ad)
 
 	for (uint16_t j = 0; j < ad->k; j++)
 	{
-		smc_sum (sum_gamma, &ad->gamma[0][ad->i][j], ad->n, ad->n * ad->k);
-		smc_sum (sum_phi, &ad->phi[0][ad->i][j], ad->n, ad->n * ad->k);
+		smc_sum (sum_gamma, &ad->gamma3[0][ad->i][j], ad->n, ad->n * ad->k);
+		smc_sum (sum_phi, &ad->phi3[0][ad->i][j], ad->n, ad->n * ad->k);
 		gcry_mpi_ec_sub (sum_gamma, sum_gamma, sum_phi, ec_ctx);
 		if (!ec_point_cmp (sum_gamma, ec_zero))
 		{
@@ -1149,9 +1501,9 @@ smc_zkp_dl (gcry_mpi_point_t v,
 	struct zkp_challenge_dl challenge;
 	struct brandt_hash_code challhash;
 	gcry_mpi_point_t        a = gcry_mpi_point_new (0);
-	gcry_mpi_t              r = gcry_mpi_new (0);
-	gcry_mpi_t              c = gcry_mpi_new (0);
-	gcry_mpi_t              z = gcry_mpi_new (0);
+	gcry_mpi_t              r = gcry_mpi_new (256);
+	gcry_mpi_t              c = gcry_mpi_new (256);
+	gcry_mpi_t              z = gcry_mpi_new (256);
 
 	/* v = xg */
 	gcry_mpi_ec_mul (v, x, ec_gen, ec_ctx);
@@ -1197,8 +1549,8 @@ smc_zkp_dl_check (const gcry_mpi_point_t v,
 	struct zkp_challenge_dl challenge;
 	struct brandt_hash_code challhash;
 	gcry_mpi_point_t        a = gcry_mpi_point_new (0);
-	gcry_mpi_t              r = gcry_mpi_new (0);
-	gcry_mpi_t              c = gcry_mpi_new (0);
+	gcry_mpi_t              r = gcry_mpi_new (256);
+	gcry_mpi_t              c = gcry_mpi_new (256);
 	gcry_mpi_point_t        left = gcry_mpi_point_new (0);
 	gcry_mpi_point_t        right = gcry_mpi_point_new (0);
 
@@ -1260,13 +1612,13 @@ smc_zkp_2dle (gcry_mpi_point_t       v,
 	gcry_mpi_t                rx;
 	gcry_mpi_point_t          a = gcry_mpi_point_new (0);
 	gcry_mpi_point_t          b = gcry_mpi_point_new (0);
-	gcry_mpi_t                r = gcry_mpi_new (0);
-	gcry_mpi_t                c = gcry_mpi_new (0);
-	gcry_mpi_t                z = gcry_mpi_new (0);
+	gcry_mpi_t                r = gcry_mpi_new (256);
+	gcry_mpi_t                c = gcry_mpi_new (256);
+	gcry_mpi_t                z = gcry_mpi_new (256);
 
 	rv = (NULL == v) ? gcry_mpi_point_new (0) : v;
 	rw = (NULL == w) ? gcry_mpi_point_new (0) : w;
-	rx = (NULL == x) ? gcry_mpi_new (0) : x;
+	rx = (NULL == x) ? gcry_mpi_new (256) : x;
 
 	if (NULL == x)
 		ec_skey_create (rx);
@@ -1339,8 +1691,8 @@ smc_zkp_2dle_check (const gcry_mpi_point_t  v,
 	struct brandt_hash_code   challhash;
 	gcry_mpi_point_t          a = gcry_mpi_point_new (0);
 	gcry_mpi_point_t          b = gcry_mpi_point_new (0);
-	gcry_mpi_t                r = gcry_mpi_new (0);
-	gcry_mpi_t                c = gcry_mpi_new (0);
+	gcry_mpi_t                r = gcry_mpi_new (256);
+	gcry_mpi_t                c = gcry_mpi_new (256);
 	gcry_mpi_point_t          left = gcry_mpi_point_new (0);
 	gcry_mpi_point_t          right = gcry_mpi_point_new (0);
 
@@ -1415,15 +1767,15 @@ smc_zkp_0og (int                    m_is_gen,
 	gcry_mpi_point_t         a2 = gcry_mpi_point_new (0);
 	gcry_mpi_point_t         b1 = gcry_mpi_point_new (0);
 	gcry_mpi_point_t         b2 = gcry_mpi_point_new (0);
-	gcry_mpi_t               d1 = gcry_mpi_new (0);
-	gcry_mpi_t               d2 = gcry_mpi_new (0);
-	gcry_mpi_t               r1 = gcry_mpi_new (0);
-	gcry_mpi_t               r2 = gcry_mpi_new (0);
-	gcry_mpi_t               c = gcry_mpi_new (0);
+	gcry_mpi_t               d1 = gcry_mpi_new (256);
+	gcry_mpi_t               d2 = gcry_mpi_new (256);
+	gcry_mpi_t               r1 = gcry_mpi_new (256);
+	gcry_mpi_t               r2 = gcry_mpi_new (256);
+	gcry_mpi_t               c = gcry_mpi_new (256);
 	gcry_mpi_t               rr;
-	gcry_mpi_t               w = gcry_mpi_new (0);
+	gcry_mpi_t               w = gcry_mpi_new (256);
 
-	rr = (NULL == r) ? gcry_mpi_new (0) : r;
+	rr = (NULL == r) ? gcry_mpi_new (256) : r;
 
 	/* beta = r*g */
 	ec_keypair_create (beta, rr);
@@ -1559,12 +1911,12 @@ smc_zkp_0og_check (const gcry_mpi_point_t y,
 	gcry_mpi_point_t         a2 = gcry_mpi_point_new (0);
 	gcry_mpi_point_t         b1 = gcry_mpi_point_new (0);
 	gcry_mpi_point_t         b2 = gcry_mpi_point_new (0);
-	gcry_mpi_t               d1 = gcry_mpi_new (0);
-	gcry_mpi_t               d2 = gcry_mpi_new (0);
-	gcry_mpi_t               r1 = gcry_mpi_new (0);
-	gcry_mpi_t               r2 = gcry_mpi_new (0);
-	gcry_mpi_t               c = gcry_mpi_new (0);
-	gcry_mpi_t               sum = gcry_mpi_new (0);
+	gcry_mpi_t               d1 = gcry_mpi_new (256);
+	gcry_mpi_t               d2 = gcry_mpi_new (256);
+	gcry_mpi_t               r1 = gcry_mpi_new (256);
+	gcry_mpi_t               r2 = gcry_mpi_new (256);
+	gcry_mpi_t               c = gcry_mpi_new (256);
+	gcry_mpi_t               sum = gcry_mpi_new (256);
 	gcry_mpi_point_t         right = gcry_mpi_point_new (0);
 	gcry_mpi_point_t         tmp = gcry_mpi_point_new (0);
 
@@ -1635,52 +1987,3 @@ smc_zkp_0og_check (const gcry_mpi_point_t y,
 		weprintf ("ret: 0x%x", ret);
 	return ret;
 }
-
-
-/* --- unused stuff, might become useful later --- */
-
-///**
-// * Clear memory that was used to store a private key.
-// *
-// * @param skey the key
-// */
-//void
-//brandt_ec_key_clear (gcry_mpi_t skey)
-//{
-//	gcry_mpi_randomize (skey, 256, GCRY_WEAK_RANDOM);
-//	gcry_mpi_release (skey);
-//}
-
-
-///**
-// * Generate a random value mod n.
-// *
-// * @param edc ECC context
-// * @return random value mod n.
-// */
-//gcry_mpi_t
-//GNUNET_CRYPTO_ecc_random_mod_n (struct GNUNET_CRYPTO_EccDlogContext *edc)
-//{
-//  gcry_mpi_t n;
-//  unsigned int highbit;
-//  gcry_mpi_t r;
-//
-//  n = gcry_mpi_ec_get_mpi ("n", edc->ctx, 1);
-//
-//  /* check public key for number of bits, bail out if key is all zeros */
-//  highbit = 256; /* Curve25519 */
-//  while ( (! gcry_mpi_test_bit (n, highbit)) &&
-//          (0 != highbit) )
-//    highbit--;
-//  GNUNET_assert (0 != highbit);
-//  /* generate fact < n (without bias) */
-//  GNUNET_assert (NULL != (r = gcry_mpi_new (0)));
-//  do {
-//    gcry_mpi_randomize (r,
-//			highbit + 1,
-//			GCRY_STRONG_RANDOM);
-//  }
-//  while (gcry_mpi_cmp (r, n) >= 0);
-//  gcry_mpi_release (n);
-//  return r;
-//}