added libtommath-0.22

Author: Tom St Denis

bn.pdf

@@ -1,7 +1,7 @@
 \documentclass[]{article}
 \begin{document}
 
-\title{LibTomMath v0.21 \\ A Free Multiple Precision Integer Library \\ http://math.libtomcrypt.org }
+\title{LibTomMath v0.22 \\ A Free Multiple Precision Integer Library \\ http://math.libtomcrypt.org }
 \author{Tom St Denis \\ tomstdenis@iahu.ca}
 \maketitle
 \newpage

bn.tex

@@ -66,8 +66,8 @@ fast_mp_invmod (mp_int * a, mp_int * b, mp_int * c)
     if ((res = mp_div_2 (&u, &u)) != MP_OKAY) {
       goto __ERR;
     }
-    /* 4.2 if A or B is odd then */
-    if (mp_iseven (&B) == 0) {
+    /* 4.2 if B is odd then */
+    if (mp_isodd (&B) == 1) {
       if ((res = mp_sub (&B, &x, &B)) != MP_OKAY) {
         goto __ERR;
       }
@@ -84,8 +84,8 @@ fast_mp_invmod (mp_int * a, mp_int * b, mp_int * c)
     if ((res = mp_div_2 (&v, &v)) != MP_OKAY) {
       goto __ERR;
     }
-    /* 5.2 if C,D are even then */
-    if (mp_iseven (&D) == 0) {
+    /* 5.2 if D is odd then */
+    if (mp_isodd (&D) == 1) {
       /* D = (D-x)/2 */
       if ((res = mp_sub (&D, &x, &D)) != MP_OKAY) {
         goto __ERR;

bn_fast_mp_invmod.c

@@ -0,0 +1,40 @@
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is library that provides for multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library is designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+#include <tommath.h>
+
+/* Counts the number of lsbs which are zero before the first zero bit */
+int mp_cnt_lsb(mp_int *a)
+{
+   int x;
+   mp_digit q;
+
+   if (mp_iszero(a) == 1) {
+      return 0;
+   }
+
+   /* scan lower digits until non-zero */
+   for (x = 0; x < a->used && a->dp[x] == 0; x++);
+   q = a->dp[x];
+   x *= DIGIT_BIT;
+
+   /* now scan this digit until a 1 is found */
+   while ((q & 1) == 0) {
+      q >>= 1;
+      x  += 1;
+   }
+
+   return x;
+}
+

bn_mp_cnt_lsb.c

@@ -58,11 +58,14 @@ mp_div_2d (mp_int * a, int b, mp_int * c, mp_int * d)
   /* shift any bit count < DIGIT_BIT */
   D = (mp_digit) (b % DIGIT_BIT);
   if (D != 0) {
-    register mp_digit *tmpc, mask;
+    register mp_digit *tmpc, mask, shift;
 
     /* mask */
     mask = (((mp_digit)1) << D) - 1;
 
+    /* shift for lsb */
+    shift = DIGIT_BIT - D;
+
     /* alias */
     tmpc = c->dp + (c->used - 1);
 
@@ -73,7 +76,7 @@ mp_div_2d (mp_int * a, int b, mp_int * c, mp_int * d)
       rr = *tmpc & mask;
 
       /* shift the current word and mix in the carry bits from the previous word */
-      *tmpc = (*tmpc >> D) | (r << (DIGIT_BIT - D));
+      *tmpc = (*tmpc >> D) | (r << shift);
       --tmpc;
 
       /* set the carry to the carry bits of the current word found above */

bn_mp_div_2d.c

@@ -1,64 +1,64 @@
-/* LibTomMath, multiple-precision integer library -- Tom St Denis
- *
- * LibTomMath is library that provides for multiple-precision
- * integer arithmetic as well as number theoretic functionality.
- *
- * The library is designed directly after the MPI library by
- * Michael Fromberger but has been written from scratch with
- * additional optimizations in place.
- *
- * The library is free for all purposes without any express
- * guarantee it works.
- *
- * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
- */
-#include <tommath.h>
-
-/* divide by three (based on routine from MPI and the GMP manual) */
-int
-mp_div_3 (mp_int * a, mp_int *c, mp_digit * d)
-{
-  mp_int   q;
-  mp_word  w, t;
-  mp_digit b;
-  int      res, ix;
-  
-  /* b = 2**DIGIT_BIT / 3 */
-  b = (((mp_word)1) << ((mp_word)DIGIT_BIT)) / ((mp_word)3);
-
-  if ((res = mp_init_size(&q, a->used)) != MP_OKAY) {
-     return res;
-  }
-  
-  q.used = a->used;
-  q.sign = a->sign;
-  w = 0;
-  for (ix = a->used - 1; ix >= 0; ix--) {
-     w = (w << ((mp_word)DIGIT_BIT)) | ((mp_word)a->dp[ix]);
-     
-     if (w >= 3) {
-        t = (w * ((mp_word)b)) >> ((mp_word)DIGIT_BIT);
-        w -= (t << ((mp_word)1)) + t;
-        while (w >= 3) {
-           t += 1;
-           w -= 3;
-        }
-      } else {
-        t = 0;
-      }
-      q.dp[ix] = (mp_digit)t;
-  }
-  
-  if (d != NULL) {
-     *d = (mp_digit)w;
-  }
-  
-  if (c != NULL) {
-     mp_clamp(&q);
-     mp_exch(&q, c);
-  }
-  mp_clear(&q);
-  
-  return res;
-}
-
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is library that provides for multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library is designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+#include <tommath.h>
+
+/* divide by three (based on routine from MPI and the GMP manual) */
+int
+mp_div_3 (mp_int * a, mp_int *c, mp_digit * d)
+{
+  mp_int   q;
+  mp_word  w, t;
+  mp_digit b;
+  int      res, ix;
+  
+  /* b = 2**DIGIT_BIT / 3 */
+  b = (((mp_word)1) << ((mp_word)DIGIT_BIT)) / ((mp_word)3);
+
+  if ((res = mp_init_size(&q, a->used)) != MP_OKAY) {
+     return res;
+  }
+  
+  q.used = a->used;
+  q.sign = a->sign;
+  w = 0;
+  for (ix = a->used - 1; ix >= 0; ix--) {
+     w = (w << ((mp_word)DIGIT_BIT)) | ((mp_word)a->dp[ix]);
+     
+     if (w >= 3) {
+        t = (w * ((mp_word)b)) >> ((mp_word)DIGIT_BIT);
+        w -= (t << ((mp_word)1)) + t;
+        while (w >= 3) {
+           t += 1;
+           w -= 3;
+        }
+      } else {
+        t = 0;
+      }
+      q.dp[ix] = (mp_digit)t;
+  }
+  
+  if (d != NULL) {
+     *d = (mp_digit)w;
+  }
+  
+  if (c != NULL) {
+     mp_clamp(&q);
+     mp_exch(&q, c);
+  }
+  mp_clear(&q);
+  
+  return res;
+}
+

bn_mp_div_3.c

@@ -21,10 +21,17 @@
  *
  * Uses Montgomery or Diminished Radix reduction [whichever appropriate]
  */
+
+#ifdef MP_LOW_MEM
+   #define TAB_SIZE 32
+#else
+   #define TAB_SIZE 256
+#endif
+
 int
 mp_exptmod_fast (mp_int * G, mp_int * X, mp_int * P, mp_int * Y, int redmode)
 {
-  mp_int  M[256], res;
+  mp_int  M[TAB_SIZE], res;
   mp_digit buf, mp;
   int     err, bitbuf, bitcpy, bitcnt, mode, digidx, x, y, winsize;
 
@@ -58,17 +65,24 @@ mp_exptmod_fast (mp_int * G, mp_int * X, mp_int * P, mp_int * Y, int redmode)
   }
 #endif
 
+  /* init M array */
+  /* init first cell */
+  if ((err = mp_init(&M[1])) != MP_OKAY) {
+     return err; 
+  }
 
-  /* init G array */
-  for (x = 0; x < (1 << winsize); x++) {
-    if ((err = mp_init (&M[x])) != MP_OKAY) {
-      for (y = 0; y < x; y++) {
+  /* now init the second half of the array */
+  for (x = 1<<(winsize-1); x < (1 << winsize); x++) {
+    if ((err = mp_init(&M[x])) != MP_OKAY) {
+      for (y = 1<<(winsize-1); y < x; y++) {
         mp_clear (&M[y]);
       }
+      mp_clear(&M[1]);
       return err;
     }
   }
 
+
   /* determine and setup reduction code */
   if (redmode == 0) {
      /* now setup montgomery  */
@@ -257,7 +271,8 @@ mp_exptmod_fast (mp_int * G, mp_int * X, mp_int * P, mp_int * Y, int redmode)
   err = MP_OKAY;
 __RES:mp_clear (&res);
 __M:
-  for (x = 0; x < (1 << winsize); x++) {
+  mp_clear(&M[1]);
+  for (x = 1<<(winsize-1); x < (1 << winsize); x++) {
     mp_clear (&M[x]);
   }
   return err;

bn_mp_exptmod_fast.c

@@ -0,0 +1,61 @@
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is library that provides for multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library is designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+#include <tommath.h>
+
+/* read a bigint from a file stream in ASCII */
+int mp_fread(mp_int *a, int radix, FILE *stream)
+{
+   int err, ch, neg, y;
+   
+   /* clear a */
+   mp_zero(a);
+   
+   /* if first digit is - then set negative */
+   ch = fgetc(stream);
+   if (ch == '-') {
+      neg = MP_NEG;
+      ch = fgetc(stream);
+   } else {
+      neg = MP_ZPOS;
+   }
+   
+   for (;;) {
+      /* find y in the radix map */
+      for (y = 0; y < radix; y++) {
+          if (mp_s_rmap[y] == ch) {
+             break;
+          }
+      }
+      if (y == radix) {
+         break;
+      }
+      
+      /* shift up and add */
+      if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
+         return err;
+      }
+      if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
+         return err;
+      }
+      
+      ch = fgetc(stream);
+   }
+   if (mp_cmp_d(a, 0) != MP_EQ) {
+      a->sign = neg;
+   }
+   
+   return MP_OKAY;
+}
+

bn_mp_fread.c

@@ -0,0 +1,47 @@
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is library that provides for multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library is designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+#include <tommath.h>
+
+int mp_fwrite(mp_int *a, int radix, FILE *stream)
+{
+   char *buf;
+   int err, len, x;
+   
+   len = mp_radix_size(a, radix);
+   if (len == 0) {
+      return MP_VAL;
+   }
+   
+   buf = malloc(len);
+   if (buf == NULL) {
+      return MP_MEM;
+   }
+   
+   if ((err = mp_toradix(a, buf, radix)) != MP_OKAY) {
+      free(buf);
+      return err;
+   }
+   
+   for (x = 0; x < len; x++) {
+       if (fputc(buf[x], stream) == EOF) {
+          free(buf);
+          return MP_VAL;
+       }
+   }
+   
+   free(buf);
+   return MP_OKAY;
+}
+