initial commit with v0.8.6.1

git-svn-id: http://mirotr.googlecode.com/svn/trunk@2 eced67a3-f377-a0ae-92ae-d6de1850b05a

1 files changed, 326 insertions, 0 deletions

diff --git a/libgcrypt-1.4.6/mpi/mpi-pow.c b/libgcrypt-1.4.6/mpi/mpi-pow.c
new file mode 100644
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+++ b/libgcrypt-1.4.6/mpi/mpi-pow.c
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+/* mpi-pow.c  -  MPI functions for exponentiation
+ * Copyright (C) 1994, 1996, 1998, 2000, 2002
+ *               2003  Free Software Foundation, Inc.
+ *
+ * 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/>.
+ *
+ * Note: This code is heavily based on the GNU MP Library.
+ *	 Actually it's the same code with only minor changes in the
+ *	 way the data is stored; this is to support the abstraction
+ *	 of an optional secure memory allocation which may be used
+ *	 to avoid revealing of sensitive data due to paging etc.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mpi-internal.h"
+#include "longlong.h"
+
+
+/****************
+ * RES = BASE ^ EXPO mod MOD
+ */
+void
+gcry_mpi_powm (gcry_mpi_t res, 
+               gcry_mpi_t base, gcry_mpi_t expo, gcry_mpi_t mod)
+{
+  /* Pointer to the limbs of the arguments, their size and signs. */
+  mpi_ptr_t  rp, ep, mp, bp;
+  mpi_size_t esize, msize, bsize, rsize;
+  int               msign, bsign, rsign;
+  /* Flags telling the secure allocation status of the arguments.  */
+  int        esec,  msec,  bsec,  rsec;  
+  /* Size of the result including space for temporary values.  */
+  mpi_size_t size;
+  /* Helper.  */
+  int mod_shift_cnt;
+  int negative_result;
+  mpi_ptr_t mp_marker = NULL;
+  mpi_ptr_t bp_marker = NULL;
+  mpi_ptr_t ep_marker = NULL;
+  mpi_ptr_t xp_marker = NULL;
+  unsigned int mp_nlimbs = 0;
+  unsigned int bp_nlimbs = 0;
+  unsigned int ep_nlimbs = 0;
+  unsigned int xp_nlimbs = 0;
+  mpi_ptr_t tspace = NULL;
+  mpi_size_t tsize = 0; 
+
+
+  esize = expo->nlimbs;
+  msize = mod->nlimbs;
+  size = 2 * msize;
+  msign = mod->sign;
+  
+  esec = mpi_is_secure(expo);
+  msec = mpi_is_secure(mod);
+  bsec = mpi_is_secure(base);
+  rsec = mpi_is_secure(res);
+
+  rp = res->d;
+  ep = expo->d;
+
+  if (!msize)
+    msize = 1 / msize;	    /* Provoke a signal.  */
+
+  if (!esize) 
+    {
+      /* Exponent is zero, result is 1 mod MOD, i.e., 1 or 0 depending
+        on if MOD equals 1.  */
+      rp[0] = 1;
+      res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1;
+      res->sign = 0;
+      goto leave;
+    }
+
+  /* Normalize MOD (i.e. make its most significant bit set) as
+     required by mpn_divrem.  This will make the intermediate values
+     in the calculation slightly larger, but the correct result is
+     obtained after a final reduction using the original MOD value. */
+  mp_nlimbs = msec? msize:0;
+  mp = mp_marker = mpi_alloc_limb_space(msize, msec);
+  count_leading_zeros (mod_shift_cnt, mod->d[msize-1]);
+  if (mod_shift_cnt)
+    _gcry_mpih_lshift (mp, mod->d, msize, mod_shift_cnt);
+  else
+    MPN_COPY( mp, mod->d, msize );
+
+  bsize = base->nlimbs;
+  bsign = base->sign;
+  if (bsize > msize) 
+    {
+      /* The base is larger than the module.  Reduce it.
+
+         Allocate (BSIZE + 1) with space for remainder and quotient.
+         (The quotient is (bsize - msize + 1) limbs.)  */
+      bp_nlimbs = bsec ? (bsize + 1):0;
+      bp = bp_marker = mpi_alloc_limb_space( bsize + 1, bsec );
+      MPN_COPY ( bp, base->d, bsize );
+      /* We don't care about the quotient, store it above the
+       * remainder, at BP + MSIZE.  */
+      _gcry_mpih_divrem( bp + msize, 0, bp, bsize, mp, msize );
+      bsize = msize;
+      /* Canonicalize the base, since we are going to multiply with it
+	 quite a few times.  */
+      MPN_NORMALIZE( bp, bsize );
+    }
+  else
+    bp = base->d;
+
+  if (!bsize)
+    {
+      res->nlimbs = 0;
+      res->sign = 0;
+      goto leave;
+    }
+
+
+  /* Make BASE, EXPO and MOD not overlap with RES.  */
+  if ( rp == bp )
+    {
+      /* RES and BASE are identical.  Allocate temp. space for BASE.  */
+      gcry_assert (!bp_marker);
+      bp_nlimbs = bsec? bsize:0;
+      bp = bp_marker = mpi_alloc_limb_space( bsize, bsec );
+      MPN_COPY(bp, rp, bsize);
+    }
+  if ( rp == ep )
+    {
+      /* RES and EXPO are identical.  Allocate temp. space for EXPO.  */
+      ep_nlimbs = esec? esize:0;
+      ep = ep_marker = mpi_alloc_limb_space( esize, esec );
+      MPN_COPY(ep, rp, esize);
+    }
+  if ( rp == mp ) 
+    {
+      /* RES and MOD are identical.  Allocate temporary space for MOD.*/
+      gcry_assert (!mp_marker);
+      mp_nlimbs = msec?msize:0;
+      mp = mp_marker = mpi_alloc_limb_space( msize, msec );
+      MPN_COPY(mp, rp, msize);
+    }
+
+  /* Copy base to the result.  */
+  if (res->alloced < size)
+    {
+      mpi_resize (res, size);
+      rp = res->d;
+    }
+  MPN_COPY ( rp, bp, bsize );
+  rsize = bsize;
+  rsign = bsign;
+  
+  /* Main processing.  */
+  {
+    mpi_size_t i;
+    mpi_ptr_t xp;
+    int c;
+    mpi_limb_t e;
+    mpi_limb_t carry_limb;
+    struct karatsuba_ctx karactx;
+    
+    xp_nlimbs = msec? (2 * (msize + 1)):0;
+    xp = xp_marker = mpi_alloc_limb_space( 2 * (msize + 1), msec );
+    
+    memset( &karactx, 0, sizeof karactx );
+    negative_result = (ep[0] & 1) && base->sign;
+    
+    i = esize - 1;
+    e = ep[i];
+    count_leading_zeros (c, e);
+    e = (e << c) << 1;     /* Shift the expo bits to the left, lose msb.  */
+    c = BITS_PER_MPI_LIMB - 1 - c;
+
+    /* Main loop.
+     
+       Make the result be pointed to alternately by XP and RP.  This
+       helps us avoid block copying, which would otherwise be
+       necessary with the overlap restrictions of
+       _gcry_mpih_divmod. With 50% probability the result after this
+       loop will be in the area originally pointed by RP (==RES->d),
+       and with 50% probability in the area originally pointed to by XP. */
+    for (;;)
+      {
+        while (c) 
+          {
+            mpi_ptr_t tp;
+            mpi_size_t xsize;
+            
+            /*mpih_mul_n(xp, rp, rp, rsize);*/
+            if ( rsize < KARATSUBA_THRESHOLD )
+              _gcry_mpih_sqr_n_basecase( xp, rp, rsize );
+            else 
+              {
+                if ( !tspace ) 
+                  {
+                    tsize = 2 * rsize;
+                    tspace = mpi_alloc_limb_space( tsize, 0 );
+                  }
+                else if ( tsize < (2*rsize) )
+                  {
+                    _gcry_mpi_free_limb_space (tspace, 0);
+                    tsize = 2 * rsize;
+                    tspace = mpi_alloc_limb_space (tsize, 0 );
+                  }
+                _gcry_mpih_sqr_n (xp, rp, rsize, tspace);
+              }
+
+            xsize = 2 * rsize;
+            if ( xsize > msize )
+              {
+                _gcry_mpih_divrem(xp + msize, 0, xp, xsize, mp, msize);
+                xsize = msize;
+              }
+
+            tp = rp; rp = xp; xp = tp;
+            rsize = xsize;
+
+            if ( (mpi_limb_signed_t)e < 0 )
+              {
+                /*mpih_mul( xp, rp, rsize, bp, bsize );*/
+                if( bsize < KARATSUBA_THRESHOLD ) 
+                  _gcry_mpih_mul ( xp, rp, rsize, bp, bsize );
+                else 
+                  _gcry_mpih_mul_karatsuba_case (xp, rp, rsize, bp, bsize,
+                                                 &karactx);
+                
+                xsize = rsize + bsize;
+                if ( xsize > msize ) 
+                  {
+                    _gcry_mpih_divrem(xp + msize, 0, xp, xsize, mp, msize);
+                    xsize = msize;
+                  }
+                
+                tp = rp; rp = xp; xp = tp;
+                rsize = xsize;
+              }
+            e <<= 1;
+            c--;
+          }
+
+        i--;
+        if ( i < 0 )
+          break;
+        e = ep[i];
+        c = BITS_PER_MPI_LIMB;
+      }
+
+    /* We shifted MOD, the modulo reduction argument, left
+       MOD_SHIFT_CNT steps.  Adjust the result by reducing it with the
+       original MOD.
+
+       Also make sure the result is put in RES->d (where it already
+       might be, see above).  */
+    if ( mod_shift_cnt ) 
+      {
+        carry_limb = _gcry_mpih_lshift( res->d, rp, rsize, mod_shift_cnt);
+        rp = res->d;
+        if ( carry_limb )
+          {
+            rp[rsize] = carry_limb;
+            rsize++;
+          }
+      }
+    else if (res->d != rp)
+      {
+        MPN_COPY (res->d, rp, rsize);
+        rp = res->d;
+      }
+
+    if ( rsize >= msize ) 
+      {
+        _gcry_mpih_divrem(rp + msize, 0, rp, rsize, mp, msize);
+        rsize = msize;
+      }
+
+    /* Remove any leading zero words from the result.  */
+    if ( mod_shift_cnt )
+      _gcry_mpih_rshift( rp, rp, rsize, mod_shift_cnt);
+    MPN_NORMALIZE (rp, rsize);
+    
+    _gcry_mpih_release_karatsuba_ctx (&karactx );
+  }
+
+  /* Fixup for negative results.  */
+  if ( negative_result && rsize )
+    {
+      if ( mod_shift_cnt )
+        _gcry_mpih_rshift( mp, mp, msize, mod_shift_cnt);
+      _gcry_mpih_sub( rp, mp, msize, rp, rsize);
+      rsize = msize;
+      rsign = msign;
+      MPN_NORMALIZE(rp, rsize);
+    }
+  gcry_assert (res->d == rp);
+  res->nlimbs = rsize;
+  res->sign = rsign;
+  
+ leave:
+  if (mp_marker)
+    _gcry_mpi_free_limb_space( mp_marker, mp_nlimbs );
+  if (bp_marker)
+    _gcry_mpi_free_limb_space( bp_marker, bp_nlimbs );
+  if (ep_marker)
+    _gcry_mpi_free_limb_space( ep_marker, ep_nlimbs );
+  if (xp_marker)
+    _gcry_mpi_free_limb_space( xp_marker, xp_nlimbs );
+  if (tspace)
+    _gcry_mpi_free_limb_space( tspace, 0 );
+}
+