ltc_tommath.h

这是由Rinick编写的加解密函数库。最近找了不少关于加解密的C源码

/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was 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, [e-mail], http://math.libtomcrypt.org
 */
#ifndef BN_H_
#define BN_H_

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>

#include <tommath_class.h>

#undef MIN
#define MIN(x,y) ((x)<(y)?(x):(y))
#undef MAX
#define MAX(x,y) ((x)>(y)?(x):(y))

#ifdef __cplusplus
extern "C" {

/* C++ compilers don't like assigning void * to mp_digit * */
#define  OPT_CAST(x)  (x *)

#else

/* C on the other hand doesn't care */
#define  OPT_CAST(x)

#endif


/* detect 64-bit mode if possible */
#if defined(__x86_64__) 
   #if !(defined(MP_64BIT) && defined(MP_16BIT) && defined(MP_8BIT))
      #define MP_64BIT
   #endif
#endif

/* some default configurations.
 *
 * A "mp_digit" must be able to hold DIGIT_BIT + 1 bits
 * A "mp_word" must be able to hold 2*DIGIT_BIT + 1 bits
 *
 * At the very least a mp_digit must be able to hold 7 bits
 * [any size beyond that is ok provided it doesn't overflow the data type]
 */
#ifdef MP_8BIT
   typedef unsigned char      mp_digit;
   typedef unsigned short     mp_word;
#elif defined(MP_16BIT)
   typedef unsigned short     mp_digit;
   typedef unsigned long      mp_word;
#elif defined(MP_64BIT)
   /* for GCC only on supported platforms */
#ifndef CRYPT
   typedef unsigned long long ulong64;
   typedef signed long long   long64;
#endif

   typedef unsigned long      mp_digit;
   typedef unsigned long      mp_word __attribute__ ((mode(TI)));

   #define DIGIT_BIT          60
#else
   /* this is the default case, 28-bit digits */
   
   /* this is to make porting into LibTomCrypt easier :-) */
#ifndef CRYPT
   #if defined(_MSC_VER) || defined(__BORLANDC__) 
      typedef unsigned __int64   ulong64;
      typedef signed __int64     long64;
   #else
      typedef unsigned long long ulong64;
      typedef signed long long   long64;
   #endif
#endif

   typedef unsigned long      mp_digit;
   typedef ulong64            mp_word;

#ifdef MP_31BIT   
   /* this is an extension that uses 31-bit digits */
   #define DIGIT_BIT          31
#else
   /* default case is 28-bit digits, defines MP_28BIT as a handy macro to test */
   #define DIGIT_BIT          28
   #define MP_28BIT
#endif   
#endif

/* define heap macros */
#ifndef CRYPT
   /* default to libc stuff */
   #ifndef XMALLOC 
       #define XMALLOC  malloc
       #define XFREE    free
       #define XREALLOC realloc
       #define XCALLOC  calloc
   #else
      /* prototypes for our heap functions */
      extern void *XMALLOC(size_t n);
      extern void *XREALLOC(void *p, size_t n);
      extern void *XCALLOC(size_t n, size_t s);
      extern void XFREE(void *p);
   #endif
#endif


/* otherwise the bits per digit is calculated automatically from the size of a mp_digit */
#ifndef DIGIT_BIT
   #define DIGIT_BIT     ((int)((CHAR_BIT * sizeof(mp_digit) - 1)))  /* bits per digit */
#endif

#define MP_DIGIT_BIT     DIGIT_BIT
#define MP_MASK          ((((mp_digit)1)<<((mp_digit)DIGIT_BIT))-((mp_digit)1))
#define MP_DIGIT_MAX     MP_MASK

/* equalities */
#define MP_LT        -1   /* less than */
#define MP_EQ         0   /* equal to */
#define MP_GT         1   /* greater than */

#define MP_ZPOS       0   /* positive integer */
#define MP_NEG        1   /* negative */

#define MP_OKAY       0   /* ok result */
#define MP_MEM        -2  /* out of mem */
#define MP_VAL        -3  /* invalid input */
#define MP_RANGE      MP_VAL

#define MP_YES        1   /* yes response */
#define MP_NO         0   /* no response */

/* Primality generation flags */
#define LTM_PRIME_BBS      0x0001 /* BBS style prime */
#define LTM_PRIME_SAFE     0x0002 /* Safe prime (p-1)/2 == prime */
#define LTM_PRIME_2MSB_ON  0x0008 /* force 2nd MSB to 1 */

typedef int           mp_err;

/* you'll have to tune these... */
extern int KARATSUBA_MUL_CUTOFF,
           KARATSUBA_SQR_CUTOFF,
           TOOM_MUL_CUTOFF,
           TOOM_SQR_CUTOFF;

/* define this to use lower memory usage routines (exptmods mostly) */
/* #define MP_LOW_MEM */

/* default precision */
#ifndef MP_PREC
   #ifndef MP_LOW_MEM
      #define MP_PREC                 64     /* default digits of precision */
   #else
      #define MP_PREC                 8      /* default digits of precision */
   #endif   
#endif

/* size of comba arrays, should be at least 2 * 2**(BITS_PER_WORD - BITS_PER_DIGIT*2) */
#define MP_WARRAY               (1 << (sizeof(mp_word) * CHAR_BIT - 2 * DIGIT_BIT + 1))

/* the infamous mp_int structure */
typedef struct  {
    int used, alloc, sign;
    mp_digit *dp;
} mp_int;

/* callback for mp_prime_random, should fill dst with random bytes and return how many read [upto len] */
typedef int ltm_prime_callback(unsigned char *dst, int len, void *dat);


#define USED(m)    ((m)->used)
#define DIGIT(m,k) ((m)->dp[(k)])
#define SIGN(m)    ((m)->sign)

/* error code to char* string */
char *mp_error_to_string(int code);

/* ---> init and deinit bignum functions <--- */
/* init a bignum */
int mp_init(mp_int *a);

/* free a bignum */
void mp_clear(mp_int *a);

/* init a null terminated series of arguments */
int mp_init_multi(mp_int *mp, ...);

/* clear a null terminated series of arguments */
void mp_clear_multi(mp_int *mp, ...);

/* exchange two ints */
void mp_exch(mp_int *a, mp_int *b);

/* shrink ram required for a bignum */
int mp_shrink(mp_int *a);

/* grow an int to a given size */
int mp_grow(mp_int *a, int size);

/* init to a given number of digits */
int mp_init_size(mp_int *a, int size);

/* ---> Basic Manipulations <--- */
#define mp_iszero(a) (((a)->used == 0) ? MP_YES : MP_NO)
#define mp_iseven(a) (((a)->used > 0 && (((a)->dp[0] & 1) == 0)) ? MP_YES : MP_NO)
#define mp_isodd(a)  (((a)->used > 0 && (((a)->dp[0] & 1) == 1)) ? MP_YES : MP_NO)

/* set to zero */
void mp_zero(mp_int *a);

/* set to a digit */
void mp_set(mp_int *a, mp_digit b);

/* set a 32-bit const */
int mp_set_int(mp_int *a, unsigned long b);

/* get a 32-bit value */
unsigned long mp_get_int(mp_int * a);

/* initialize and set a digit */
int mp_init_set (mp_int * a, mp_digit b);

/* initialize and set 32-bit value */
int mp_init_set_int (mp_int * a, unsigned long b);

/* copy, b = a */
int mp_copy(mp_int *a, mp_int *b);

/* inits and copies, a = b */
int mp_init_copy(mp_int *a, mp_int *b);

/* trim unused digits */
void mp_clamp(mp_int *a);

/* ---> digit manipulation <--- */

/* right shift by "b" digits */
void mp_rshd(mp_int *a, int b);

/* left shift by "b" digits */
int mp_lshd(mp_int *a, int b);

/* c = a / 2**b */
int mp_div_2d(mp_int *a, int b, mp_int *c, mp_int *d);

/* b = a/2 */
int mp_div_2(mp_int *a, mp_int *b);

/* c = a * 2**b */
int mp_mul_2d(mp_int *a, int b, mp_int *c);

/* b = a*2 */
int mp_mul_2(mp_int *a, mp_int *b);

/* c = a mod 2**d */
int mp_mod_2d(mp_int *a, int b, mp_int *c);

/* computes a = 2**b */
int mp_2expt(mp_int *a, int b);

/* Counts the number of lsbs which are zero before the first zero bit */
int mp_cnt_lsb(mp_int *a);

/* I Love Earth! */

/* makes a pseudo-random int of a given size */
int mp_rand(mp_int *a, int digits);

/* ---> binary operations <--- */
/* c = a XOR b  */
int mp_xor(mp_int *a, mp_int *b, mp_int *c);

/* c = a OR b */
int mp_or(mp_int *a, mp_int *b, mp_int *c);

/* c = a AND b */
int mp_and(mp_int *a, mp_int *b, mp_int *c);