--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/ecc/ltc_ecc_mulmod_timing.c	Thu Jan 11 02:41:05 2007 +0000
@@ -0,0 +1,167 @@
+/* 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, [email protected], http://libtomcrypt.com
+ */
+
+/* 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 "tomcrypt.h"
+
+/**
+  @file ltc_ecc_mulmod_timing.c
+  ECC Crypto, Tom St Denis
+*/  
+
+#ifdef MECC
+
+#ifdef LTC_ECC_TIMING_RESISTANT
+
+/**
+   Perform a point multiplication  (timing resistant)
+   @param k    The scalar to multiply by
+   @param G    The base point
+   @param R    [out] Destination for kG
+   @param modulus  The modulus of the field the ECC curve is in
+   @param map      Boolean whether to map back to affine or not (1==map, 0 == leave in projective)
+   @return CRYPT_OK on success
+*/
+int ltc_ecc_mulmod(void *k, ecc_point *G, ecc_point *R, void *modulus, int map)
+{
+   ecc_point *tG, *M[3];
+   int        i, j, err;
+   void       *mu, *mp;
+   unsigned long buf;
+   int        first, bitbuf, bitcpy, bitcnt, mode, digidx;
+
+   LTC_ARGCHK(k       != NULL);
+   LTC_ARGCHK(G       != NULL);
+   LTC_ARGCHK(R       != NULL);
+   LTC_ARGCHK(modulus != NULL);
+
+   /* init montgomery reduction */
+   if ((err = mp_montgomery_setup(modulus, &mp)) != CRYPT_OK) {
+      return err;
+   }
+   if ((err = mp_init(&mu)) != CRYPT_OK) {
+      mp_montgomery_free(mp);
+      return err;
+   }
+   if ((err = mp_montgomery_normalization(mu, modulus)) != CRYPT_OK) {
+      mp_clear(mu);
+      mp_montgomery_free(mp);
+      return err;
+   }
+
+  /* alloc ram for window temps */
+  for (i = 0; i < 3; i++) {
+      M[i] = ltc_ecc_new_point();
+      if (M[i] == NULL) {
+         for (j = 0; j < i; j++) {
+             ltc_ecc_del_point(M[j]);
+         }
+         mp_clear(mu);
+         mp_montgomery_free(mp);
+         return CRYPT_MEM;
+      }
+  }
+
+   /* make a copy of G incase R==G */
+   tG = ltc_ecc_new_point();
+   if (tG == NULL)                                                                   { err = CRYPT_MEM; goto done; }
+
+   /* tG = G  and convert to montgomery */
+   if ((err = mp_mulmod(G->x, mu, modulus, tG->x)) != CRYPT_OK)                      { goto done; }
+   if ((err = mp_mulmod(G->y, mu, modulus, tG->y)) != CRYPT_OK)                      { goto done; }
+   if ((err = mp_mulmod(G->z, mu, modulus, tG->z)) != CRYPT_OK)                      { goto done; }
+   mp_clear(mu);
+   mu = NULL;
+   
+   /* calc the M tab */
+   /* M[0] == G */
+   if ((err = mp_copy(tG->x, M[0]->x)) != CRYPT_OK)                                  { goto done; }
+   if ((err = mp_copy(tG->y, M[0]->y)) != CRYPT_OK)                                  { goto done; }
+   if ((err = mp_copy(tG->z, M[0]->z)) != CRYPT_OK)                                  { goto done; }
+   /* M[1] == 2G */
+   if ((err = ltc_mp.ecc_ptdbl(tG, M[1], modulus, mp)) != CRYPT_OK)                  { goto done; }
+
+   /* setup sliding window */
+   mode   = 0;
+   bitcnt = 1;
+   buf    = 0;
+   digidx = mp_get_digit_count(k) - 1;
+   bitcpy = bitbuf = 0;
+   first  = 1;
+
+   /* perform ops */
+   for (;;) {
+     /* grab next digit as required */
+      if (--bitcnt == 0) {
+         if (digidx == -1) {
+            break;
+         }
+         buf    = mp_get_digit(k, digidx);
+         bitcnt = (int) MP_DIGIT_BIT;
+         --digidx;
+      }
+
+      /* grab the next msb from the ltiplicand */
+      i = (buf >> (MP_DIGIT_BIT - 1)) & 1;
+      buf <<= 1;
+
+      if (mode == 0 && i == 0) {
+         /* dummy operations */
+         if ((err = ltc_mp.ecc_ptadd(M[0], M[1], M[2], modulus, mp)) != CRYPT_OK)    { goto done; }
+         if ((err = ltc_mp.ecc_ptdbl(M[1], M[2], modulus, mp)) != CRYPT_OK)          { goto done; }
+         continue;
+      }
+
+      if (mode == 0 && i == 1) {
+         mode = 1;
+         /* dummy operations */
+         if ((err = ltc_mp.ecc_ptadd(M[0], M[1], M[2], modulus, mp)) != CRYPT_OK)    { goto done; }
+         if ((err = ltc_mp.ecc_ptdbl(M[1], M[2], modulus, mp)) != CRYPT_OK)          { goto done; }
+         continue;
+      }
+
+      if ((err = ltc_mp.ecc_ptadd(M[0], M[1], M[i^1], modulus, mp)) != CRYPT_OK)     { goto done; }
+      if ((err = ltc_mp.ecc_ptdbl(M[i], M[i], modulus, mp)) != CRYPT_OK)             { goto done; }
+   }
+
+   /* copy result out */
+   if ((err = mp_copy(M[0]->x, R->x)) != CRYPT_OK)                                   { goto done; }
+   if ((err = mp_copy(M[0]->y, R->y)) != CRYPT_OK)                                   { goto done; }
+   if ((err = mp_copy(M[0]->z, R->z)) != CRYPT_OK)                                   { goto done; }
+
+   /* map R back from projective space */
+   if (map) {
+      err = ltc_ecc_map(R, modulus, mp);
+   } else {
+      err = CRYPT_OK;
+   }
+done:
+   if (mu != NULL) {
+      mp_clear(mu);
+   }
+   mp_montgomery_free(mp);
+   ltc_ecc_del_point(tG);
+   for (i = 0; i < 3; i++) {
+       ltc_ecc_del_point(M[i]);
+   }
+   return err;
+}
+
+#endif
+#endif
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ltc_ecc_mulmod_timing.c,v $ */
+/* $Revision: 1.11 $ */
+/* $Date: 2006/12/04 22:17:46 $ */
+