diff --git a/smc.c b/smc.c
index 52c1b3b..c58b1c2 100644
--- a/smc.c
+++ b/smc.c
@@ -45,8 +45,11 @@ smc_zkp_dl (gcry_mpi_point_t v, gcry_mpi_point_t g, gcry_mpi_t x,
 	gcry_mpi_t z = gcry_mpi_new (0);
 
 	brandt_ec_keypair_create_base (a, &z, g);
+
+	/* compute challange c */
 	/**TODO: generate c from HASH(g,v,a) and don't output it */
 	brandt_ec_skey_create (c);
+
 	*r = gcry_mpi_new (0);
 	gcry_mpi_mul (*r, *c, x);
 	gcry_mpi_add (*r, *r, z);
@@ -54,6 +57,7 @@ smc_zkp_dl (gcry_mpi_point_t v, gcry_mpi_point_t g, gcry_mpi_t x,
 	gcry_mpi_release (z);
 }
 
+
 /**
  * smc_zkp_dl_check
  *
@@ -84,6 +88,51 @@ smc_zkp_dl_check (gcry_mpi_point_t v, gcry_mpi_point_t g, gcry_mpi_point_t a,
 	return ret;
 }
 
+
+void
+smc_zkp_2dle (gcry_mpi_point_t v, gcry_mpi_point_t w, gcry_mpi_point_t g1, gcry_mpi_point_t g2, gcry_mpi_t x, gcry_mpi_point_t *a, gcry_mpi_point_t *b, gcry_mpi_t *c, gcry_mpi_t *r)
+{
+	gcry_mpi_t z = gcry_mpi_new (0);
+
+	brandt_ec_keypair_create_base (a, &z, g1);
+	*b = gcry_mpi_point_new(0);
+	gcry_mpi_ec_mul(*b, z, g2, ec_ctx);
+
+	/* compute challange c */
+	/**TODO: generate c from HASH(g1,g2,v,w,a,b) and don't output it */
+	brandt_ec_skey_create (c);
+
+	*r = gcry_mpi_new (0);
+	gcry_mpi_mul (*r, *c, x);
+	gcry_mpi_add (*r, *r, z);
+
+	gcry_mpi_release (z);
+}
+
+
+int
+smc_zkp_2dle_check (gcry_mpi_point_t v, gcry_mpi_point_t w, gcry_mpi_point_t g1, gcry_mpi_point_t g2, gcry_mpi_point_t a, gcry_mpi_point_t b, gcry_mpi_t c, gcry_mpi_t r)
+{
+	int              ret;
+	gcry_mpi_point_t left = gcry_mpi_point_new (0);
+	gcry_mpi_point_t right = gcry_mpi_point_new (0);
+
+	gcry_mpi_ec_mul (left, r, g1, ec_ctx);
+	gcry_mpi_ec_mul (right, c, v, ec_ctx);
+	gcry_mpi_ec_add (right, a, right, ec_ctx);
+	ret = brandt_ec_point_cmp (left, right);
+
+	gcry_mpi_ec_mul (left, r, g2, ec_ctx);
+	gcry_mpi_ec_mul (right, c, w, ec_ctx);
+	gcry_mpi_ec_add (right, b, right, ec_ctx);
+	ret &= brandt_ec_point_cmp (left, right);
+
+	gcry_mpi_point_release (left);
+	gcry_mpi_point_release (right);
+
+	return ret;
+}
+
 //GEN
 //smc_hextodec (const char *s)
 //{
diff --git a/smc.h b/smc.h
index 5ea81e8..c2826c2 100644
--- a/smc.h
+++ b/smc.h
@@ -27,4 +27,7 @@
 void smc_zkp_dl (gcry_mpi_point_t v, gcry_mpi_point_t g, gcry_mpi_t x, gcry_mpi_point_t *a, gcry_mpi_t *c, gcry_mpi_t *r);
 int smc_zkp_dl_check (gcry_mpi_point_t v, gcry_mpi_point_t g, gcry_mpi_point_t a, gcry_mpi_t c, gcry_mpi_t r);
 
+void smc_zkp_2dle (gcry_mpi_point_t v, gcry_mpi_point_t w, gcry_mpi_point_t g1, gcry_mpi_point_t g2, gcry_mpi_t x, gcry_mpi_point_t *a, gcry_mpi_point_t *b, gcry_mpi_t *c, gcry_mpi_t *r);
+int smc_zkp_2dle_check (gcry_mpi_point_t v, gcry_mpi_point_t w, gcry_mpi_point_t g1, gcry_mpi_point_t g2, gcry_mpi_point_t a, gcry_mpi_point_t b, gcry_mpi_t c, gcry_mpi_t r);
+
 #endif // ifndef _BRANDT_SMC_H
diff --git a/test_crypto.c b/test_crypto.c
index d692055..5103e0e 100644
--- a/test_crypto.c
+++ b/test_crypto.c
@@ -85,6 +85,58 @@ test_smc_zkp_dl ()
 	gcry_mpi_point_release (v);
 }
 
+int
+test_smc_zkp_2dle ()
+{
+	static int       first = 1;
+	gcry_mpi_t       c;
+	gcry_mpi_t       r;
+	gcry_mpi_t       s;
+	gcry_mpi_t       x;
+	gcry_mpi_point_t a;
+	gcry_mpi_point_t b;
+	gcry_mpi_point_t g1;
+	gcry_mpi_point_t g2;
+	gcry_mpi_point_t v = gcry_mpi_point_new (0);
+	gcry_mpi_point_t w = gcry_mpi_point_new (0);
+
+	check (v, "no pub1 key initialized");
+	check (w, "no pub2 key initialized");
+	brandt_ec_keypair_create (&g1, &s);
+	gcry_mpi_release (s);
+	brandt_ec_keypair_create (&g2, &s);
+	check (g1, "no gen1 created");
+	check (g2, "no gen2 created");
+
+	if (first)
+	{
+		gcry_mpi_ec_mul (g1, GCRYMPI_CONST_ONE, ec_gen, ec_ctx);
+		gcry_mpi_ec_mul (g2, GCRYMPI_CONST_ONE, ec_gen, ec_ctx);
+		first = 0;
+	}
+
+	brandt_ec_skey_create (&x);
+	check (x, "no sec key created");
+	gcry_mpi_ec_mul (v, x, g1, ec_ctx);
+	check (v, "no pub1 key created");
+	gcry_mpi_ec_mul (w, x, g2, ec_ctx);
+	check (w, "no pub2 key created");
+
+	smc_zkp_2dle (v, w, g1, g2, x, &a, &b, &c, &r);
+	check (!smc_zkp_2dle_check (v, w, g1, g2, a, b, c, r), "zkp was false, should be true");
+
+	gcry_mpi_release (c);
+	gcry_mpi_release (r);
+	gcry_mpi_release (s);
+	gcry_mpi_release (x);
+	gcry_mpi_point_release (a);
+	gcry_mpi_point_release (b);
+	gcry_mpi_point_release (g1);
+	gcry_mpi_point_release (g2);
+	gcry_mpi_point_release (v);
+	gcry_mpi_point_release (w);
+}
+
 int
 main (int argc, char *argv[])
 {