Diff: crypto/ltc/ltc_ecc_map.c

Revision:

4:cbaf466d717d

Parent:

2:527a66d0a1a9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/crypto/ltc/ltc_ecc_map.c	Tue Jun 10 14:23:09 2014 +0000
@@ -0,0 +1,94 @@
+/*
+MiniTLS - A super trimmed down TLS/SSL Library for embedded devices
+Author: Donatien Garnier
+Copyright (C) 2013-2014 AppNearMe Ltd
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+*//* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
+ */
+
+/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b
+ *
+ * All curves taken from NIST recommendation paper of July 1999
+ * Available at http://csrc.nist.gov/cryptval/dss.htm
+ */
+#include "ltc.h"
+
+/**
+  @file ltc_ecc_map.c
+  ECC Crypto, Tom St Denis
+*/  
+
+#ifdef LTC_MECC
+
+/**
+  Map a projective jacbobian point back to affine space
+  @param P        [in/out] The point to map
+  @param modulus  The modulus of the field the ECC curve is in
+  @param mp       The "b" value from montgomery_setup()
+  @return MINITLS_OK on success
+*/
+int ltc_ecc_map(ecc_point *P, void *modulus, void *mp)
+{
+   fp_int t1, t2;
+   int   err;
+
+   LTC_ARGCHK(P       != NULL);
+   LTC_ARGCHK(modulus != NULL);
+   LTC_ARGCHK(mp      != NULL);
+
+   if ((err = mp_init_multi(&t1, &t2, NULL)) != MINITLS_OK) {
+      return MINITLS_ERR_MEMORY;
+   }
+
+   /* first map z back to normal */
+   /*if ((err = */mp_montgomery_reduce(&P->z, modulus, mp);/*) != MINITLS_OK)           { goto done; }*/
+
+   /* get 1/z */
+   if ((err = mp_invmod(&P->z, modulus, &t1)) != MINITLS_OK)                      { goto done; }
+ 
+   /* get 1/z^2 and 1/z^3 */
+   /*if ((err = */mp_sqr(&t1, &t2);/*) != MINITLS_OK)                                    { goto done; }*/
+   if ((err = mp_mod(&t2, modulus, &t2)) != MINITLS_OK)                           { goto done; }
+   /*if ((err =*/ mp_mul(&t1, &t2, &t1);/*) != MINITLS_OK)                                { goto done; }*/
+   /*if ((err =*/ mp_mod(&t1, modulus, &t1);/*) != MINITLS_OK)                           { goto done; }*/
+
+   /* multiply against x/y */
+   /*if ((err =*/ mp_mul(&P->x, &t2, &P->x);/*) != MINITLS_OK)                            { goto done; }*/
+   /*if ((err =*/ mp_montgomery_reduce(&P->x, modulus, mp);/*) != MINITLS_OK)           { goto done; }*/
+   /*if ((err =*/ mp_mul(&P->y, &t1, &P->y);/*) != MINITLS_OK)                            { goto done; }*/
+   /*if ((err =*/ mp_montgomery_reduce(&P->y, modulus, mp);/*) != MINITLS_OK)           { goto done; }*/
+   /*if ((err =*/ mp_set(&P->z, 1);/*) != MINITLS_OK)                                   { goto done; }*/
+
+   err = MINITLS_OK;
+done:
+   mp_clear_multi(&t1, &t2, NULL);
+   return err;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ltc_ecc_map.c,v $ */
+/* $Revision: 1.7 $ */
+/* $Date: 2007/05/12 14:32:35 $ */
+