twofish.c

该压缩包中包括 tom的加密函数库及pdf说明 ,以及Rinick s ECC：椭圆曲线非对称加密密钥生成器

/* 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, [e-mail], http://libtomcrypt.org
 */

 /** 
   @file twofish.c
   Implementation of Twofish by Tom St Denis 
 */
#include "tomcrypt.h"

#ifdef TWOFISH

/* first TWOFISH_ALL_TABLES must ensure TWOFISH_TABLES is defined */
#ifdef TWOFISH_ALL_TABLES
#ifndef TWOFISH_TABLES
#define TWOFISH_TABLES
#endif
#endif

const struct ltc_cipher_descriptor twofish_desc =
{
    "twofish",
    7,
    16, 32, 16, 16,
    &twofish_setup,
    &twofish_ecb_encrypt,
    &twofish_ecb_decrypt,
    &twofish_test,
    &twofish_done,
    &twofish_keysize,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

/* the two polynomials */
#define MDS_POLY          0x169
#define RS_POLY           0x14D

/* The 4x4 MDS Linear Transform */
static const unsigned char MDS[4][4] = {
    { 0x01, 0xEF, 0x5B, 0x5B },
    { 0x5B, 0xEF, 0xEF, 0x01 },
    { 0xEF, 0x5B, 0x01, 0xEF },
    { 0xEF, 0x01, 0xEF, 0x5B }
};

/* The 4x8 RS Linear Transform */
static const unsigned char RS[4][8] = {
    { 0x01, 0xA4, 0x55, 0x87, 0x5A, 0x58, 0xDB, 0x9E },
    { 0xA4, 0x56, 0x82, 0xF3, 0X1E, 0XC6, 0X68, 0XE5 },
    { 0X02, 0XA1, 0XFC, 0XC1, 0X47, 0XAE, 0X3D, 0X19 },
    { 0XA4, 0X55, 0X87, 0X5A, 0X58, 0XDB, 0X9E, 0X03 }
};

/* sbox usage orderings */
static const unsigned char qord[4][5] = {
   { 1, 1, 0, 0, 1 },
   { 0, 1, 1, 0, 0 },
   { 0, 0, 0, 1, 1 },
   { 1, 0, 1, 1, 0 }
};

#ifdef TWOFISH_TABLES

#include "twofish_tab.c"

#define sbox(i, x) ((ulong32)SBOX[i][(x)&255])

#else

/* The Q-box tables */
static const unsigned char qbox[2][4][16] = {
{
   { 0x8, 0x1, 0x7, 0xD, 0x6, 0xF, 0x3, 0x2, 0x0, 0xB, 0x5, 0x9, 0xE, 0xC, 0xA, 0x4 },
   { 0xE, 0XC, 0XB, 0X8, 0X1, 0X2, 0X3, 0X5, 0XF, 0X4, 0XA, 0X6, 0X7, 0X0, 0X9, 0XD },
   { 0XB, 0XA, 0X5, 0XE, 0X6, 0XD, 0X9, 0X0, 0XC, 0X8, 0XF, 0X3, 0X2, 0X4, 0X7, 0X1 },
   { 0XD, 0X7, 0XF, 0X4, 0X1, 0X2, 0X6, 0XE, 0X9, 0XB, 0X3, 0X0, 0X8, 0X5, 0XC, 0XA }
},
{
   { 0X2, 0X8, 0XB, 0XD, 0XF, 0X7, 0X6, 0XE, 0X3, 0X1, 0X9, 0X4, 0X0, 0XA, 0XC, 0X5 },
   { 0X1, 0XE, 0X2, 0XB, 0X4, 0XC, 0X3, 0X7, 0X6, 0XD, 0XA, 0X5, 0XF, 0X9, 0X0, 0X8 },
   { 0X4, 0XC, 0X7, 0X5, 0X1, 0X6, 0X9, 0XA, 0X0, 0XE, 0XD, 0X8, 0X2, 0XB, 0X3, 0XF },
   { 0xB, 0X9, 0X5, 0X1, 0XC, 0X3, 0XD, 0XE, 0X6, 0X4, 0X7, 0XF, 0X2, 0X0, 0X8, 0XA }
}
};

/* computes S_i[x] */
#ifdef LTC_CLEAN_STACK
static ulong32 _sbox(int i, ulong32 x)
#else
static ulong32 sbox(int i, ulong32 x)
#endif
{
   unsigned char a0,b0,a1,b1,a2,b2,a3,b3,a4,b4,y;

   /* a0,b0 = [x/16], x mod 16 */
   a0 = (unsigned char)((x>>4)&15);
   b0 = (unsigned char)((x)&15);

   /* a1 = a0 ^ b0 */
   a1 = a0 ^ b0;

   /* b1 = a0 ^ ROR(b0, 1) ^ 8a0 */
   b1 = (a0 ^ ((b0<<3)|(b0>>1)) ^ (a0<<3)) & 15;

   /* a2,b2 = t0[a1], t1[b1] */
   a2 = qbox[i][0][(int)a1];
   b2 = qbox[i][1][(int)b1];

   /* a3 = a2 ^ b2 */
   a3 = a2 ^ b2;

   /* b3 = a2 ^ ROR(b2, 1) ^ 8a2 */
   b3 = (a2 ^ ((b2<<3)|(b2>>1)) ^ (a2<<3)) & 15;

   /* a4,b4 = t2[a3], t3[b3] */
   a4 = qbox[i][2][(int)a3];
   b4 = qbox[i][3][(int)b3];

   /* y = 16b4 + a4 */
   y = (b4 << 4) + a4;

   /* return result */
   return (ulong32)y;
}

#ifdef LTC_CLEAN_STACK
static ulong32 sbox(int i, ulong32 x)
{
   ulong32 y;
   y = _sbox(i, x);
   burn_stack(sizeof(unsigned char) * 11);
   return y;
}
#endif /* LTC_CLEAN_STACK */

#endif /* TWOFISH_TABLES */

/* computes ab mod p */
static ulong32 gf_mult(ulong32 a, ulong32 b, ulong32 p)
{
   ulong32 result, B[2], P[2];

   P[1] = p;
   B[1] = b;
   result = P[0] = B[0] = 0;

   /* unrolled branchless GF multiplier */
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; a >>= 1;  B[1] = P[B[1]>>7] ^ (B[1] << 1); 
   result ^= B[a&1]; 

   return result;
}

/* computes [y0 y1 y2 y3] = MDS . [x0] */
#ifndef TWOFISH_TABLES
static ulong32 mds_column_mult(unsigned char in, int col)
{
   ulong32 x01, x5B, xEF;

   x01 = in;
   x5B = gf_mult(in, 0x5B, MDS_POLY);
   xEF = gf_mult(in, 0xEF, MDS_POLY);

   switch (col) {
       case 0:
          return (x01 << 0 ) |
                 (x5B << 8 ) |
                 (xEF << 16) |
                 (xEF << 24);
       case 1:
          return (xEF << 0 ) |
                 (xEF << 8 ) |
                 (x5B << 16) |
                 (x01 << 24);
       case 2:
          return (x5B << 0 ) |
                 (xEF << 8 ) |
                 (x01 << 16) |
                 (xEF << 24);
       case 3:
          return (x5B << 0 ) |
                 (x01 << 8 ) |
                 (xEF << 16) |
                 (x5B << 24);
   }
   /* avoid warnings, we'd never get here normally but just to calm compiler warnings... */
   return 0;
}

#else /* !TWOFISH_TABLES */

#define mds_column_mult(x, i) mds_tab[i][x]

#endif /* TWOFISH_TABLES */

/* Computes [y0 y1 y2 y3] = MDS . [x0 x1 x2 x3] */
static void mds_mult(const unsigned char *in, unsigned char *out)
{
  int x;
  ulong32 tmp;
  for (tmp = x = 0; x < 4; x++) {
      tmp ^= mds_column_mult(in[x], x);
  }
  STORE32L(tmp, out);
}

#ifdef TWOFISH_ALL_TABLES
/* computes [y0 y1 y2 y3] = RS . [x0 x1 x2 x3 x4 x5 x6 x7] */
static void rs_mult(const unsigned char *in, unsigned char *out)
{
   ulong32 tmp;
   tmp = rs_tab0[in[0]] ^ rs_tab1[in[1]] ^ rs_tab2[in[2]] ^ rs_tab3[in[3]] ^
         rs_tab4[in[4]] ^ rs_tab5[in[5]] ^ rs_tab6[in[6]] ^ rs_tab7[in[7]];
   STORE32L(tmp, out);
}

#else /* !TWOFISH_ALL_TABLES */

/* computes [y0 y1 y2 y3] = RS . [x0 x1 x2 x3 x4 x5 x6 x7] */
static void rs_mult(const unsigned char *in, unsigned char *out)
{
  int x, y;
  for (x = 0; x < 4; x++) {
      out[x] = 0;
      for (y = 0; y < 8; y++) {
          out[x] ^= gf_mult(in[y], RS[x][y], RS_POLY);
      }
  }
}

#endif

/* computes h(x) */
static void h_func(const unsigned char *in, unsigned char *out, unsigned char *M, int k, int offset)
{
  int x;
  unsigned char y[4];
  for (x = 0; x < 4; x++) {
      y[x] = in[x];
 }
  switch (k) {
     case 4:
            y[0] = (unsigned char)(sbox(1, (ulong32)y[0]) ^ M[4 * (6 + offset) + 0]);
            y[1] = (unsigned char)(sbox(0, (ulong32)y[1]) ^ M[4 * (6 + offset) + 1]);
            y[2] = (unsigned char)(sbox(0, (ulong32)y[2]) ^ M[4 * (6 + offset) + 2]);
            y[3] = (unsigned char)(sbox(1, (ulong32)y[3]) ^ M[4 * (6 + offset) + 3]);
     case 3:
            y[0] = (unsigned char)(sbox(1, (ulong32)y[0]) ^ M[4 * (4 + offset) + 0]);
            y[1] = (unsigned char)(sbox(1, (ulong32)y[1]) ^ M[4 * (4 + offset) + 1]);
            y[2] = (unsigned char)(sbox(0, (ulong32)y[2]) ^ M[4 * (4 + offset) + 2]);
            y[3] = (unsigned char)(sbox(0, (ulong32)y[3]) ^ M[4 * (4 + offset) + 3]);
     case 2:
            y[0] = (unsigned char)(sbox(1, sbox(0, sbox(0, (ulong32)y[0]) ^ M[4 * (2 + offset) + 0]) ^ M[4 * (0 + offset) + 0]));
            y[1] = (unsigned char)(sbox(0, sbox(0, sbox(1, (ulong32)y[1]) ^ M[4 * (2 + offset) + 1]) ^ M[4 * (0 + offset) + 1]));
            y[2] = (unsigned char)(sbox(1, sbox(1, sbox(0, (ulong32)y[2]) ^ M[4 * (2 + offset) + 2]) ^ M[4 * (0 + offset) + 2]));
            y[3] = (unsigned char)(sbox(0, sbox(1, sbox(1, (ulong32)y[3]) ^ M[4 * (2 + offset) + 3]) ^ M[4 * (0 + offset) + 3]));
  }
  mds_mult(y, out);
}

#ifndef TWOFISH_SMALL

/* for GCC we don't use pointer aliases */
#if defined(__GNUC__)
    #define S1 skey->twofish.S[0]
    #define S2 skey->twofish.S[1]
    #define S3 skey->twofish.S[2]
    #define S4 skey->twofish.S[3]
#endif

/* the G function */
#define g_func(x, dum)  (S1[byte(x,0)] ^ S2[byte(x,1)] ^ S3[byte(x,2)] ^ S4[byte(x,3)])
#define g1_func(x, dum) (S2[byte(x,0)] ^ S3[byte(x,1)] ^ S4[byte(x,2)] ^ S1[byte(x,3)])

#else

#ifdef LTC_CLEAN_STACK
static ulong32 _g_func(ulong32 x, symmetric_key *key)
#else
static ulong32 g_func(ulong32 x, symmetric_key *key)
#endif
{
   unsigned char g, i, y, z;
   ulong32 res;

   res = 0;
   for (y = 0; y < 4; y++) {
       z = key->twofish.start;

       /* do unkeyed substitution */
       g = sbox(qord[y][z++], (x >> (8*y)) & 255);

       /* first subkey */
       i = 0;

       /* do key mixing+sbox until z==5 */
       while (z != 5) {
          g = g ^ key->twofish.S[4*i++ + y];
          g = sbox(qord[y][z++], g);
       }

       /* multiply g by a column of the MDS */
       res ^= mds_column_mult(g, y);
   }
   return res;
}

#define g1_func(x, key) g_func(ROLc(x, 8), key)

#ifdef LTC_CLEAN_STACK
static ulong32 g_func(ulong32 x, symmetric_key *key)
{
    ulong32 y;
    y = _g_func(x, key);
    burn_stack(sizeof(unsigned char) * 4 + sizeof(ulong32));
    return y;
}
#endif /* LTC_CLEAN_STACK */

#endif /* TWOFISH_SMALL */

 /**
    Initialize the Twofish block cipher
    @param key The symmetric key you wish to pass
    @param keylen The key length in bytes
    @param num_rounds The number of rounds desired (0 for default)
    @param skey The key in as scheduled by this function.
    @return CRYPT_OK if successful
 */
#ifdef LTC_CLEAN_STACK
static int _twofish_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
#else
int twofish_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
#endif
{
#ifndef TWOFISH_SMALL
   unsigned char S[4*4], tmpx0, tmpx1;
#endif
   int k, x, y;
   unsigned char tmp[4], tmp2[4], M[8*4];
   ulong32 A, B;