view libtomcrypt/notes/etc/whirlgen.c @ 994:5c5ade336926

Prefer stronger algorithms in algorithm negotiation. Prefer diffie-hellman-group14-sha1 (2048 bit) over diffie-hellman-group1-sha1 (1024 bit). Due to meet-in-the-middle attacks the effective key length of three key 3DES is 112 bits. AES is stronger and faster then 3DES. Prefer to delay the start of compression until after authentication has completed. This avoids exposing compression code to attacks from unauthenticated users. (github pull request #9)
author Fedor Brunner <fedor.brunner@azet.sk>
date Fri, 23 Jan 2015 23:00:25 +0800
parents 1b9e69c058d2
children f849a5ca2efc
line wrap: on
line source

#include <stdio.h>

unsigned E[16] =  { 1, 0xb, 9, 0xc, 0xd, 6, 0xf, 3, 0xe, 8, 7, 4, 0xa, 2, 5, 0 };
unsigned Ei[16];
unsigned R[16] =  { 7, 0xc, 0xb, 0xd, 0xe, 4, 9, 0xf, 6, 3, 8, 0xa, 2, 5, 1, 0 };
unsigned cir[8][8] = { 
 {1, 1, 4, 1, 8, 5, 2, 9 },
}; 


unsigned gf_mul(unsigned a, unsigned b)
{
   unsigned r;
   
   r = 0;
   while (a) {
      if (a & 1) r ^= b;
      a >>= 1;
      b = (b << 1) ^ (b & 0x80 ? 0x11d : 0x00);
   }
   return r;
}

unsigned sbox(unsigned x)
{
   unsigned a, b, w;
   
   a = x >> 4;
   b = x & 15;
   
   a = E[a]; b = Ei[b];
   w = a ^ b; w = R[w];
   a = E[a ^ w]; b = Ei[b ^ w];
   
   
   return (a << 4) | b;
}

int main(void)
{
   unsigned x, y;
   
   for (x = 0; x < 16; x++) Ei[E[x]] = x;
   
//   for (x = 0; x < 16; x++) printf("%2x ", sbox(x));
   for (y = 1; y < 8; y++) {
      for (x = 0; x < 8; x++) {
          cir[y][x] = cir[y-1][(x-1)&7];
      }
   }

/*   
   printf("\n");
   for (y = 0; y < 8; y++) {
       for (x = 0; x < 8; x++) printf("%2d ", cir[y][x]);
       printf("\n");
   }
*/

   for (y = 0; y < 8; y++) {
       printf("static const ulong64 sbox%d[] = {\n", y);
       for (x = 0; x < 256; ) {
           printf("CONST64(0x%02x%02x%02x%02x%02x%02x%02x%02x)",
              gf_mul(sbox(x), cir[y][0]),
              gf_mul(sbox(x), cir[y][1]),
              gf_mul(sbox(x), cir[y][2]),
              gf_mul(sbox(x), cir[y][3]),
              gf_mul(sbox(x), cir[y][4]),
              gf_mul(sbox(x), cir[y][5]),
              gf_mul(sbox(x), cir[y][6]),
              gf_mul(sbox(x), cir[y][7]));
           if (x < 255) printf(", ");
           if (!(++x & 3)) printf("\n");
       }
       printf("};\n\n");
  }
  
  printf("static const ulong64 cont[] = {\n");
  for (y = 0; y <= 10; y++) {
      printf("CONST64(0x");
      for (x = 0; x < 8; x++) {
         printf("%02x", sbox((8*y + x)&255));
      }
      printf("),\n");
  }
  printf("};\n\n");
  return 0;
   
}



/* $Source: /cvs/libtom/libtomcrypt/notes/etc/whirlgen.c,v $ */
/* $Revision: 1.2 $ */
/* $Date: 2005/05/05 14:35:58 $ */