add (de)serialization + test. add some docu and stubs

3 files changed, 298 insertions, 115 deletions

diff --git a/crypto.c b/crypto.c
index 186a704..f892e7d 100644
--- a/crypto.c
+++ b/crypto.c
@@ -88,89 +88,6 @@ brandt_hash (const void *block, size_t size, struct brandt_hash_code *ret)
 }
 
 
-/* --- MPI --- */
-
-/**
- * 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 (void *buf, size_t size, size_t target)
-{
-	char *p = buf;
-
-	if (size < target)
-	{
-		memmove (&p[target - size], buf, size);
-		memset (buf, 0, target - size);
-	}
-}
-
-
-/**
- * Output the given MPI value to the given buffer in
- * network byte order.
- * The MPI @a val may not be negative.
- *
- * @param buf where to output to
- * @param size number of bytes in @a buf
- * @param val value to write to @a buf
- */
-void
-brandt_mpi_print_unsigned (void *buf, size_t size, gcry_mpi_t val)
-{
-	size_t       rsize;
-	gcry_error_t rc;
-
-	if (gcry_mpi_get_flag (val, GCRYMPI_FLAG_OPAQUE))
-	{
-		/* Store opaque MPIs left aligned into the buffer.  */
-		unsigned int nbits;
-		const void   *p;
-
-		p = gcry_mpi_get_opaque (val, &nbits);
-		brandt_assert (NULL != p);
-		rsize = (nbits + 7) / 8;
-		if (rsize > size)
-			rsize = size;
-		memcpy (buf, p, rsize);
-		if (rsize < size)
-			memset (((char *)buf) + rsize, 0, size - rsize);
-	}
-	else
-	{
-		/* Store regular MPIs as unsigned integers right aligned into the buffer. */
-		rsize = size;
-		rc = gcry_mpi_print (GCRYMPI_FMT_USG, buf, rsize, &rsize, val);
-		brandt_assert_gpgerr (rc);
-		adjust (buf, rsize, size);
-	}
-}
-
-
-/**
- * Convert data buffer into MPI value.
- * The buffer is interpreted as network
- * byte order, unsigned integer.
- *
- * @param result where to store MPI value (allocated)
- * @param data raw data (GCRYMPI_FMT_USG)
- * @param size number of bytes in @a data
- */
-void
-brandt_mpi_scan_unsigned (gcry_mpi_t *result, const void *data, size_t size)
-{
-	gcry_error_t rc;
-
-	rc = gcry_mpi_scan (result, GCRYMPI_FMT_USG, data, size, &size);
-	brandt_assert_gpgerr (rc);
-}
-
-
 /* --- EC --- */
 
 /**
@@ -289,6 +206,145 @@ ec_point_cmp (const gcry_mpi_point_t a, const gcry_mpi_point_t b)
 }
 
 
+/**
+ * mpi_serialize outputs the given MPI value to the given destination buffer in
+ * network byte order. The MPI @a src may not be negative.
+ *
+ * @param[out] dst where to output to
+ * @param[in] src value to write to @a dst
+ */
+void
+mpi_serialize (struct ec_mpi *dst, gcry_mpi_t src)
+{
+	size_t       rsize = 0;
+	unsigned int nbits;
+	const void   *p;
+	gcry_error_t rc;
+
+	if (gcry_mpi_get_flag (src, GCRYMPI_FLAG_OPAQUE))
+	{
+		/* Store opaque MPIs left aligned into the buffer. Used by Ed25519 point
+		 * compression */
+		p = gcry_mpi_get_opaque (src, &nbits);
+		brandt_assert (p);
+		rsize = (nbits + 7) / 8;
+		if (rsize > sizeof (struct ec_mpi))
+			rsize = sizeof (struct ec_mpi);
+		memcpy (dst, p, rsize);
+		if (rsize < sizeof (struct ec_mpi))
+			memset (((char *)dst) + rsize, 0, sizeof (struct ec_mpi) - rsize);
+	}
+	else
+	{
+		/* Store regular MPIs as unsigned ints right aligned into the buffer. */
+		rc = gcry_mpi_print (GCRYMPI_FMT_USG, (void *)dst,
+		                     sizeof (struct ec_mpi), &rsize, src);
+		brandt_assert_gpgerr (rc);
+
+		/* Shift the output to the right, if shorter than available space */
+		if (rsize && rsize < sizeof (struct ec_mpi))
+		{
+			memmove (&dst[sizeof (struct ec_mpi) - rsize], dst, rsize);
+			memset (dst, 0, sizeof (struct ec_mpi) - rsize);
+		}
+	}
+}
+
+
+/**
+ * mpi_parse converts src buffer into MPI value.
+ * The buffer is interpreted as network byte order, unsigned integer.
+ *
+ * @param[out] dst where to store MPI value. Must be initialized.
+ * @param[in] src raw data source (GCRYMPI_FMT_USG)
+ */
+void
+mpi_parse (gcry_mpi_t dst, const struct ec_mpi *src)
+{
+	gcry_mpi_t   ret;
+	gcry_error_t rc;
+
+	rc = gcry_mpi_scan (&ret, GCRYMPI_FMT_USG,
+	                    src, sizeof (struct ec_mpi), NULL);
+	brandt_assert_gpgerr (rc);
+
+	gcry_mpi_snatch (dst, ret);
+}
+
+
+/**
+ * ec_point_serialize outputs the given curve point to the @a dst buffer.
+ *
+ * @param[out] dst where to write the raw data to
+ * @param[in] src curve point to write to @a dst
+ */
+void
+ec_point_serialize (struct ec_mpi *dst, const gcry_mpi_point_t src)
+{
+	gcry_sexp_t  s;
+	gcry_ctx_t   ctx;
+	gcry_error_t rc;
+	gcry_mpi_t   q;
+
+	brandt_assert (dst);
+
+	rc = gcry_sexp_build (&s, NULL, "(public-key(ecc(curve " CURVE ")))");
+	brandt_assert_gpgerr (rc);
+	brandt_assert (NULL != s);
+
+	rc = gcry_mpi_ec_new (&ctx, s, NULL);
+	brandt_assert_gpgerr (rc);
+	gcry_sexp_release (s);
+
+	rc = gcry_mpi_ec_set_point ("q", src, ctx);
+	brandt_assert_gpgerr (rc);
+
+	q = gcry_mpi_ec_get_mpi ("q@eddsa", ctx, 0);
+	brandt_assert (NULL != q);
+	gcry_ctx_release (ctx);
+
+	mpi_serialize (dst, q);
+	gcry_mpi_release (q);
+}
+
+
+/**
+ * ec_point_parse parses a point on the Ed25519 curve from @a src into @a dst.
+ *
+ * @param[out] dst where to store the curve point. Must be initialized
+ * @param[in] src raw data source
+ */
+void
+ec_point_parse (gcry_mpi_point_t dst, const struct ec_mpi *src)
+{
+	gcry_sexp_t      s;
+	gcry_ctx_t       ctx;
+	gcry_mpi_point_t ret;
+	gcry_error_t     rc;
+
+	rc = gcry_sexp_build (&s, NULL, "(public-key(ecc(curve " CURVE ")(q %b)))",
+	                      sizeof (struct ec_mpi), src);
+	brandt_assert_gpgerr (rc);
+
+	rc = gcry_mpi_ec_new (&ctx, s, NULL);
+	brandt_assert_gpgerr (rc);
+	gcry_sexp_release (s);
+
+	ret = gcry_mpi_ec_get_point ("q", ctx, 0);
+	brandt_assert (ret);
+	gcry_ctx_release (ctx);
+	gcry_mpi_ec_mul (dst, GCRYMPI_CONST_ONE, ret, ec_ctx);
+}
+
+
+/**
+ * smc_init2 creates a 2 dimensional array of curve points
+ *
+ * @param[in] size1 size of the first dimension
+ * @param[in] size2 size of the second dimension
+ * @return a pointer to the array. If not used anymore use smc_free2 to reclaim
+ * the memory.
+ */
 static gcry_mpi_point_t **
 smc_init2 (uint16_t size1, uint16_t size2)
 {
@@ -310,6 +366,13 @@ smc_init2 (uint16_t size1, uint16_t size2)
 }
 
 
+/**
+ * smc_free2 releases all points in @a dst and frees the memory
+ *
+ * @param[in,out] dst The 2 dimensional array to clean up
+ * @param[in] size1 size of the first dimension
+ * @param[in] size2 size of the second dimension
+ */
 static void
 smc_free2 (gcry_mpi_point_t **dst, uint16_t size1, uint16_t size2)
 {
@@ -322,6 +385,15 @@ smc_free2 (gcry_mpi_point_t **dst, uint16_t size1, uint16_t size2)
 }
 
 
+/**
+ * smc_init3 creates a 3 dimensional array of curve points
+ *
+ * @param[in] size1 size of the first dimension
+ * @param[in] size2 size of the second dimension
+ * @param[in] size3 size of the third dimension
+ * @return a pointer to the array. If not used anymore use smc_free3 to reclaim
+ * the memory.
+ */
 static gcry_mpi_point_t ***
 smc_init3 (uint16_t size1, uint16_t size2, uint16_t size3)
 {
@@ -351,6 +423,14 @@ smc_init3 (uint16_t size1, uint16_t size2, uint16_t size3)
 }
 
 
+/**
+ * smc_free3 releases all points in @a dst and frees the memory
+ *
+ * @param[in,out] dst The 3 dimensional array to clean up
+ * @param[in] size1 size of the first dimension
+ * @param[in] size2 size of the second dimension
+ * @param[in] size3 size of the third dimension
+ */
 static void
 smc_free3 (gcry_mpi_point_t ***dst,
            uint16_t         size1,
@@ -425,6 +505,12 @@ smc_compute_pkey (struct AuctionData *ad)
 }
 
 
+/**
+ * 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
+ */
 void
 smc_gen_keyshare (struct AuctionData *ad)
 {
@@ -439,6 +525,21 @@ smc_gen_keyshare (struct AuctionData *ad)
 }
 
 
+/**
+ * smc_encrypt_bid \todo
+ *
+ * @param ad TODO
+ * @param j TODO
+ * @param a1 TODO
+ * @param a2 TODO
+ * @param b1 TODO
+ * @param b2 TODO
+ * @param c TODO
+ * @param d1 TODO
+ * @param d2 TODO
+ * @param r1 TODO
+ * @param r2 TODO
+ */
 void
 smc_encrypt_bid (struct AuctionData *ad,
                  uint16_t           j,
@@ -458,6 +559,27 @@ smc_encrypt_bid (struct AuctionData *ad,
 
 
 /**
+ * smc_compute_outcome \todo
+ *
+ * @param ad TODO
+ */
+void
+smc_compute_outcome (struct AuctionData *ad)
+{
+	uint16_t i, j;
+
+	// create temporary table with partial sums
+
+
+	for (i = 0; i < ad->n; i++)
+	{
+
+	}
+	/*\todo ZKP*/
+}
+
+
+/**
  * smc_zkp_dl
  *
  * @param v \todo
@@ -481,6 +603,7 @@ smc_zkp_dl (const gcry_mpi_point_t v,
 
 	/* compute challange c */
 	/**\todo: generate c from HASH(g,v,a) and don't output it */
+//	brandt_hash (const void *block, size_t size, struct brandt_hash_code *ret)
 	ec_skey_create (c);
 	gcry_mpi_mod (c, c, ec_n);
 
@@ -524,6 +647,19 @@ smc_zkp_dl_check (const gcry_mpi_point_t v,
 }
 
 
+/**
+ * smc_zkp_2dle \todo
+ *
+ * @param v TODO
+ * @param w TODO
+ * @param g1 TODO
+ * @param g2 TODO
+ * @param x TODO
+ * @param a TODO
+ * @param b TODO
+ * @param c TODO
+ * @param r TODO
+ */
 void
 smc_zkp_2dle (const gcry_mpi_point_t v,
               const gcry_mpi_point_t w,
@@ -552,6 +688,19 @@ smc_zkp_2dle (const gcry_mpi_point_t v,
 }
 
 
+/**
+ * smc_zkp_2dle_check \todo
+ *
+ * @param v TODO
+ * @param w TODO
+ * @param g1 TODO
+ * @param g2 TODO
+ * @param a TODO
+ * @param b TODO
+ * @param c TODO
+ * @param r TODO
+ * @return TODO
+ */
 int
 smc_zkp_2dle_check (const gcry_mpi_point_t v,
                     const gcry_mpi_point_t w,
@@ -583,6 +732,23 @@ smc_zkp_2dle_check (const gcry_mpi_point_t v,
 }
 
 
+/**
+ * smc_zkp_0og \todo
+ *
+ * @param alpha TODO
+ * @param m TODO
+ * @param y TODO
+ * @param beta TODO
+ * @param a1 TODO
+ * @param a2 TODO
+ * @param b1 TODO
+ * @param b2 TODO
+ * @param c TODO
+ * @param d1 TODO
+ * @param d2 TODO
+ * @param r1 TODO
+ * @param r2 TODO
+ */
 void
 smc_zkp_0og (gcry_mpi_point_t       alpha,
              const gcry_mpi_point_t m,
@@ -691,6 +857,23 @@ smc_zkp_0og (gcry_mpi_point_t       alpha,
 }
 
 
+/**
+ * smc_zkp_0og_check \todo
+ *
+ * @param alpha TODO
+ * @param y TODO
+ * @param beta TODO
+ * @param a1 TODO
+ * @param a2 TODO
+ * @param b1 TODO
+ * @param b2 TODO
+ * @param c TODO
+ * @param d1 TODO
+ * @param d2 TODO
+ * @param r1 TODO
+ * @param r2 TODO
+ * @return TODO
+ */
 int
 smc_zkp_0og_check (const gcry_mpi_point_t alpha,
                    const gcry_mpi_point_t y,
@@ -764,29 +947,6 @@ smc_zkp_0og_check (const gcry_mpi_point_t alpha,
 //}
 
 
-//gcry_mpi_point_t
-//deserialize_point(const struct brandt_point* data, const int len)
-//{
-//	gcry_sexp_t s;
-//	gcry_ctx_t ctx;
-//	gcry_mpi_point_t ret;
-//	gcry_error_t rc;
-//
-//	rc = gcry_sexp_build(&s, NULL, "(public-key(ecc(curve " CURVE ")(q %b)))",
-//						 len, data);
-//	brandt_assert_gpgerr(rc);
-//
-//	rc = gcry_mpi_ec_new(&ctx, s, NULL);
-//	brandt_assert_gpgerr(rc);
-//	gcry_sexp_release(s);
-//
-//	ret = gcry_mpi_ec_get_point("q", ctx, 0);
-//	brandt_assert(ret);
-//	gcry_ctx_release(ctx);
-//	return ret;
-//}
-
-
 ///**
 // * Generate a random value mod n.
 // *
diff --git a/crypto.h b/crypto.h
index aa518cd..4ccd1ca 100644
--- a/crypto.h
+++ b/crypto.h
@@ -44,17 +44,11 @@ struct brandt_hash_code {
 void brandt_hash (const void *block, size_t size, struct brandt_hash_code *ret);
 
 
-/* --- MPI --- */
-
-void brandt_mpi_print_unsigned (void *buf, size_t size, gcry_mpi_t val);
-void brandt_mpi_scan_unsigned (gcry_mpi_t *result,
-                               const void *data,
-                               size_t     size);
-
-
 /* --- EC --- */
 
-struct ec_point {
+/* used for serialized mpis and serialized curve points (they are the same size
+ * when compressed) */
+struct ec_mpi {
 	unsigned char data[256 / 8];
 };
 
diff --git a/test_crypto.c b/test_crypto.c
index a9acdde..5f72c71 100644
--- a/test_crypto.c
+++ b/test_crypto.c
@@ -68,6 +68,34 @@ test_smc_3d_array ()
 
 
 int
+test_serialization ()
+{
+	gcry_mpi_point_t oldp = gcry_mpi_point_new (0);
+	gcry_mpi_point_t newp = gcry_mpi_point_new (0);
+	gcry_mpi_t       oldi = gcry_mpi_new (0);
+	gcry_mpi_t       newi = gcry_mpi_new (0);
+	struct ec_mpi    serp;
+	struct ec_mpi    seri;
+
+	ec_keypair_create (oldp, oldi);
+
+	ec_point_serialize (&serp, oldp);
+	mpi_serialize (&seri, oldi);
+
+	ec_point_parse (newp, &serp);
+	mpi_parse (newi, &seri);
+
+	check (!ec_point_cmp (oldp, newp), "serialization changed point");
+	check (!gcry_mpi_cmp (oldi, newi), "serialization changed mpi");
+
+	gcry_mpi_point_release (oldp);
+	gcry_mpi_point_release (newp);
+	gcry_mpi_release (oldi);
+	gcry_mpi_release (newi);
+}
+
+
+int
 test_smc_zkp_dl ()
 {
 	gcry_mpi_t       c = gcry_mpi_new (0);
@@ -210,6 +238,7 @@ main (int argc, char *argv[])
 
 	for (tests_run = 0; tests_run < repeat; tests_run++)
 	{
+		run (test_serialization);
 		run (test_smc_zkp_dl);
 		run (test_smc_zkp_2dle);
 		run (test_smc_zkp_0og);