Refactor the ECC code into 3 files.

* cipher/ecc-common.h, cipher/ecc-curves.c, cipher/ecc-misc.c: New.
* cipher/Makefile.am (EXTRA_libcipher_la_SOURCES): Add new files.
* configure.ac (GCRYPT_PUBKEY_CIPHERS): Add new .c files.
* cipher/ecc.c (curve_aliases, ecc_domain_parms_t, domain_parms)
(scanval): Move to ecc-curves.c.
(fill_in_curve): Move to ecc-curve.c as _gcry_ecc_fill_in_curve.
(ecc_get_curve): Move to ecc-curve.c as _gcry_ecc_get_curve.
(_gcry_mpi_ec_ec2os): Move to ecc-misc.c.
(ec2os): Move to ecc-misc.c as _gcry_ecc_ec2os.
(os2ec): Move to ecc-misc.c as _gcry_ecc_os2ec.
(point_set): Move as inline function to ecc-common.h.
(_gcry_ecc_curve_free): Move to ecc-misc.c as _gcry_ecc_curve_free.
(_gcry_ecc_curve_copy): Move to ecc-misc.c as _gcry_ecc_curve_copy.
(mpi_from_keyparam, point_from_keyparam): Move to ecc-curves.c.
(_gcry_mpi_ec_new): Move to ecc-curves.c.
(ecc_get_param): Move to ecc-curves.c as _gcry_ecc_get_param.
(ecc_get_param_sexp): Move to ecc-curves.c as _gcry_ecc_get_param_sexp.

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 183 insertions, 0 deletions

diff --git a/cipher/ecc-misc.c b/cipher/ecc-misc.c
new file mode 100644
index 00000000..5e06bef9
--- /dev/null
+++ b/cipher/ecc-misc.c
@@ -0,0 +1,183 @@
+/* ecc-misc.c  -  Elliptic Curve miscellaneous functions
+ * Copyright (C) 2007, 2008, 2010, 2011 Free Software Foundation, Inc.
+ * Copyright (C) 2013 g10 Code GmbH
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * Libgcrypt 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "g10lib.h"
+#include "mpi.h"
+#include "context.h"
+#include "ec-context.h"
+#include "ecc-common.h"
+
+
+/*
+ * Release a curve object.
+ */
+void
+_gcry_ecc_curve_free (elliptic_curve_t *E)
+{
+  mpi_free (E->p); E->p = NULL;
+  mpi_free (E->a); E->a = NULL;
+  mpi_free (E->b);  E->b = NULL;
+  _gcry_mpi_point_free_parts (&E->G);
+  mpi_free (E->n);  E->n = NULL;
+}
+
+
+/*
+ * Return a copy of a curve object.
+ */
+elliptic_curve_t
+_gcry_ecc_curve_copy (elliptic_curve_t E)
+{
+  elliptic_curve_t R;
+
+  R.p = mpi_copy (E.p);
+  R.a = mpi_copy (E.a);
+  R.b = mpi_copy (E.b);
+  _gcry_mpi_point_init (&R.G);
+  point_set (&R.G, &E.G);
+  R.n = mpi_copy (E.n);
+
+  return R;
+}
+
+
+gcry_mpi_t
+_gcry_ecc_ec2os (gcry_mpi_t x, gcry_mpi_t y, gcry_mpi_t p)
+{
+  gpg_error_t err;
+  int pbytes = (mpi_get_nbits (p)+7)/8;
+  size_t n;
+  unsigned char *buf, *ptr;
+  gcry_mpi_t result;
+
+  buf = gcry_xmalloc ( 1 + 2*pbytes );
+  *buf = 04; /* Uncompressed point.  */
+  ptr = buf+1;
+  err = gcry_mpi_print (GCRYMPI_FMT_USG, ptr, pbytes, &n, x);
+  if (err)
+    log_fatal ("mpi_print failed: %s\n", gpg_strerror (err));
+  if (n < pbytes)
+    {
+      memmove (ptr+(pbytes-n), ptr, n);
+      memset (ptr, 0, (pbytes-n));
+    }
+  ptr += pbytes;
+  err = gcry_mpi_print (GCRYMPI_FMT_USG, ptr, pbytes, &n, y);
+  if (err)
+    log_fatal ("mpi_print failed: %s\n", gpg_strerror (err));
+  if (n < pbytes)
+    {
+      memmove (ptr+(pbytes-n), ptr, n);
+      memset (ptr, 0, (pbytes-n));
+    }
+
+  err = gcry_mpi_scan (&result, GCRYMPI_FMT_USG, buf, 1+2*pbytes, NULL);
+  if (err)
+    log_fatal ("mpi_scan failed: %s\n", gpg_strerror (err));
+  gcry_free (buf);
+
+  return result;
+}
+
+
+/* Convert POINT into affine coordinates using the context CTX and
+   return a newly allocated MPI.  If the conversion is not possible
+   NULL is returned.  This function won't print an error message.  */
+gcry_mpi_t
+_gcry_mpi_ec_ec2os (gcry_mpi_point_t point, mpi_ec_t ectx)
+{
+  gcry_mpi_t g_x, g_y, result;
+
+  g_x = mpi_new (0);
+  g_y = mpi_new (0);
+  if (_gcry_mpi_ec_get_affine (g_x, g_y, point, ectx))
+    result = NULL;
+  else
+    result = _gcry_ecc_ec2os (g_x, g_y, ectx->p);
+  mpi_free (g_x);
+  mpi_free (g_y);
+
+  return result;
+}
+
+
+/* RESULT must have been initialized and is set on success to the
+   point given by VALUE.  */
+gcry_error_t
+_gcry_ecc_os2ec (mpi_point_t result, gcry_mpi_t value)
+{
+  gcry_error_t err;
+  size_t n;
+  unsigned char *buf;
+  gcry_mpi_t x, y;
+
+  n = (mpi_get_nbits (value)+7)/8;
+  buf = gcry_xmalloc (n);
+  err = gcry_mpi_print (GCRYMPI_FMT_USG, buf, n, &n, value);
+  if (err)
+    {
+      gcry_free (buf);
+      return err;
+    }
+  if (n < 1)
+    {
+      gcry_free (buf);
+      return GPG_ERR_INV_OBJ;
+    }
+  if (*buf != 4)
+    {
+      gcry_free (buf);
+      return GPG_ERR_NOT_IMPLEMENTED; /* No support for point compression.  */
+    }
+  if ( ((n-1)%2) )
+    {
+      gcry_free (buf);
+      return GPG_ERR_INV_OBJ;
+    }
+  n = (n-1)/2;
+  err = gcry_mpi_scan (&x, GCRYMPI_FMT_USG, buf+1, n, NULL);
+  if (err)
+    {
+      gcry_free (buf);
+      return err;
+    }
+  err = gcry_mpi_scan (&y, GCRYMPI_FMT_USG, buf+1+n, n, NULL);
+  gcry_free (buf);
+  if (err)
+    {
+      mpi_free (x);
+      return err;
+    }
+
+  mpi_set (result->x, x);
+  mpi_set (result->y, y);
+  mpi_set_ui (result->z, 1);
+
+  mpi_free (x);
+  mpi_free (y);
+
+  return 0;
+}