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

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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

/* emits an optimized version of SAFER+ ... only does encrypt so far... */

#include <stdio.h>
#include <string.h>

/* This is the "Armenian" Shuffle.  It takes the input from b and stores it in b2 */
#define SHUF\
    b2[0] = b[8]; b2[1] = b[11]; b2[2] = b[12]; b2[3] = b[15];   \
    b2[4] = b[2]; b2[5] = b[1]; b2[6] = b[6]; b2[7] = b[5];      \
    b2[8] = b[10]; b2[9] = b[9]; b2[10] = b[14]; b2[11] = b[13]; \
    b2[12] = b[0]; b2[13] = b[7]; b2[14] = b[4]; b2[15] = b[3]; memcpy(b, b2, sizeof(b));

/* This is the inverse shuffle.  It takes from b and gives to b2 */
#define iSHUF(b, b2)                                               \
    b2[0] = b[12]; b2[1] = b[5]; b2[2] = b[4]; b2[3] = b[15];      \
    b2[4] = b[14]; b2[5] = b[7]; b2[6] = b[6]; b2[7] = b[13];      \
    b2[8] = b[0]; b2[9] = b[9]; b2[10] = b[8]; b2[11] = b[1];      \
    b2[12] = b[2]; b2[13] = b[11]; b2[14] = b[10]; b2[15] = b[3]; memcpy(b, b2, sizeof(b));
    
#define ROUND(b, i)                                                                        \
    b[0]  = (safer_ebox[(b[0] ^ skey->saferp.K[i][0]) & 255] + skey->saferp.K[i+1][0]) & 255;    \
    b[1]  = safer_lbox[(b[1] + skey->saferp.K[i][1]) & 255] ^ skey->saferp.K[i+1][1];            \
    b[2]  = safer_lbox[(b[2] + skey->saferp.K[i][2]) & 255] ^ skey->saferp.K[i+1][2];            \
    b[3]  = (safer_ebox[(b[3] ^ skey->saferp.K[i][3]) & 255] + skey->saferp.K[i+1][3]) & 255;    \
    b[4]  = (safer_ebox[(b[4] ^ skey->saferp.K[i][4]) & 255] + skey->saferp.K[i+1][4]) & 255;    \
    b[5]  = safer_lbox[(b[5] + skey->saferp.K[i][5]) & 255] ^ skey->saferp.K[i+1][5];            \
    b[6]  = safer_lbox[(b[6] + skey->saferp.K[i][6]) & 255] ^ skey->saferp.K[i+1][6];            \
    b[7]  = (safer_ebox[(b[7] ^ skey->saferp.K[i][7]) & 255] + skey->saferp.K[i+1][7]) & 255;    \
    b[8]  = (safer_ebox[(b[8] ^ skey->saferp.K[i][8]) & 255] + skey->saferp.K[i+1][8]) & 255;    \
    b[9]  = safer_lbox[(b[9] + skey->saferp.K[i][9]) & 255] ^ skey->saferp.K[i+1][9];            \
    b[10] = safer_lbox[(b[10] + skey->saferp.K[i][10]) & 255] ^ skey->saferp.K[i+1][10];         \
    b[11] = (safer_ebox[(b[11] ^ skey->saferp.K[i][11]) & 255] + skey->saferp.K[i+1][11]) & 255; \
    b[12] = (safer_ebox[(b[12] ^ skey->saferp.K[i][12]) & 255] + skey->saferp.K[i+1][12]) & 255; \
    b[13] = safer_lbox[(b[13] + skey->saferp.K[i][13]) & 255] ^ skey->saferp.K[i+1][13];         \
    b[14] = safer_lbox[(b[14] + skey->saferp.K[i][14]) & 255] ^ skey->saferp.K[i+1][14];         \
    b[15] = (safer_ebox[(b[15] ^ skey->saferp.K[i][15]) & 255] + skey->saferp.K[i+1][15]) & 255;        

int main(void)
{
   int b[16], b2[16], x, y, z;
   
/* -- ENCRYPT ---  */
   for (x = 0; x < 16; x++) b[x] = x;
   /* emit encrypt preabmle  */
printf(
"void saferp_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)\n"
"{\n"
"   int x;\n"
"   unsigned char b[16];\n"
"\n"
"   LTC_ARGCHK(pt   != NULL);\n"
"   LTC_ARGCHK(ct   != NULL);\n"
"   LTC_ARGCHK(skey != NULL);\n"
"\n"
"   /* do eight rounds */\n"
"   for (x = 0; x < 16; x++) {\n"
"       b[x] = pt[x];\n"
"   }\n");   

   /* do 8 rounds of ROUND; LT; */
   for (x = 0; x < 8; x++) {
       /* ROUND(..., x*2) */
       for (y = 0; y < 16; y++) {
printf("b[%d] = (safer_%cbox[(b[%d] %c skey->saferp.K[%d][%d]) & 255] %c skey->saferp.K[%d][%d]) & 255;\n",
          b[y], "elle"[y&3], b[y], "^++^"[y&3],      x*2, y, "+^^+"[y&3], x*2+1, y);
       }
       
       /* LT */
       for (y = 0; y < 4; y++) {
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[0], b[0], b[1], b[0], b[1]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[2], b[2], b[3], b[3], b[2]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[4], b[4], b[5], b[5], b[4]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[6], b[6], b[7], b[7], b[6]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[8], b[8], b[9], b[9], b[8]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[10], b[10], b[11], b[11], b[10]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[12], b[12], b[13], b[13], b[12]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[14], b[14], b[15], b[15], b[14]);
      if (y < 3) {
         SHUF;
      }         
      }   
  }
  
printf(
"   if (skey->saferp.rounds <= 8) {\n");
/* finish */
   for (x = 0; x < 16; x++) {
   printf(
"      ct[%d] = (b[%d] %c skey->saferp.K[skey->saferp.rounds*2][%d]) & 255;\n",
       x, b[x], "^++^"[x&3], x);
   }   
   printf("      return;\n   }\n");
  
  /* 192-bit keys */
printf(  
"   /* 192-bit key? */\n"
"   if (skey->saferp.rounds > 8) {\n");
  
   /* do 4 rounds of ROUND; LT; */
   for (x = 8; x < 12; x++) {
       /* ROUND(..., x*2) */
       for (y = 0; y < 16; y++) {
printf("b[%d] = (safer_%cbox[(b[%d] %c skey->saferp.K[%d][%d]) & 255] %c skey->saferp.K[%d][%d]) & 255;\n",
          b[y], "elle"[y&3], b[y], "^++^"[y&3],      x*2, y, "+^^+"[y&3], x*2+1, y);
       }
       
       /* LT */
       for (y = 0; y < 4; y++) {
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[0], b[0], b[1], b[0], b[1]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[2], b[2], b[3], b[3], b[2]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[4], b[4], b[5], b[5], b[4]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[6], b[6], b[7], b[7], b[6]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[8], b[8], b[9], b[9], b[8]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[10], b[10], b[11], b[11], b[10]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[12], b[12], b[13], b[13], b[12]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[14], b[14], b[15], b[15], b[14]);
      if (y < 3) {
         SHUF;
      }         
      }   
  }
printf("}\n");
  
printf(
"   if (skey->saferp.rounds <= 12) {\n");
/* finish */
   for (x = 0; x < 16; x++) {
   printf(
"      ct[%d] = (b[%d] %c skey->saferp.K[skey->saferp.rounds*2][%d]) & 255;\n",
       x, b[x], "^++^"[x&3], x);
   }   
   printf("      return;\n   }\n");

  /* 256-bit keys */
printf(  
"   /* 256-bit key? */\n"
"   if (skey->saferp.rounds > 12) {\n");
  
   /* do 4 rounds of ROUND; LT; */
   for (x = 12; x < 16; x++) {
       /* ROUND(..., x*2) */
       for (y = 0; y < 16; y++) {
printf("b[%d] = (safer_%cbox[(b[%d] %c skey->saferp.K[%d][%d]) & 255] %c skey->saferp.K[%d][%d]) & 255;\n",
          b[y], "elle"[y&3], b[y], "^++^"[y&3],      x*2, y, "+^^+"[y&3], x*2+1, y);
       }
       
       /* LT */
       for (y = 0; y < 4; y++) {
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[0], b[0], b[1], b[0], b[1]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[2], b[2], b[3], b[3], b[2]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[4], b[4], b[5], b[5], b[4]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[6], b[6], b[7], b[7], b[6]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[8], b[8], b[9], b[9], b[8]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[10], b[10], b[11], b[11], b[10]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[12], b[12], b[13], b[13], b[12]);
printf("   b[%d]  = (b[%d] + (b[%d] = (b[%d] + b[%d]) & 255)) & 255;\n", b[14], b[14], b[15], b[15], b[14]);
      if (y < 3) {
         SHUF;
      }         
      }   
  }
/* finish */
   for (x = 0; x < 16; x++) {
   printf(
"      ct[%d] = (b[%d] %c skey->saferp.K[skey->saferp.rounds*2][%d]) & 255;\n",
       x, b[x], "^++^"[x&3], x);
   }   
   printf("   return;\n");
printf("   }\n}\n\n");

   return 0;
}


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