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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 0cbe8f6dbf9e
children f849a5ca2efc
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line source

/* 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, [email protected], http://libtomcrypt.com
 */

/**
  @file kasumi.c
  Implementation of the 3GPP Kasumi block cipher
  Derived from the 3GPP standard source code
*/

#include "tomcrypt.h"

#ifdef LTC_KASUMI

typedef unsigned u16;

#define ROL16(x, y) ((((x)<<(y)) | ((x)>>(16-(y)))) & 0xFFFF)

const struct ltc_cipher_descriptor kasumi_desc = {
   "kasumi",
   21,
   16, 16, 8, 8,
   &kasumi_setup,
   &kasumi_ecb_encrypt,
   &kasumi_ecb_decrypt,
   &kasumi_test,
   &kasumi_done,
   &kasumi_keysize,
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

static u16 FI( u16 in, u16 subkey )
{
   u16 nine, seven;
   static const u16 S7[128] = {
      54, 50, 62, 56, 22, 34, 94, 96, 38, 6, 63, 93, 2, 18,123, 33,
      55,113, 39,114, 21, 67, 65, 12, 47, 73, 46, 27, 25,111,124, 81,
      53, 9,121, 79, 52, 60, 58, 48,101,127, 40,120,104, 70, 71, 43,
      20,122, 72, 61, 23,109, 13,100, 77, 1, 16, 7, 82, 10,105, 98,
      117,116, 76, 11, 89,106, 0,125,118, 99, 86, 69, 30, 57,126, 87,
      112, 51, 17, 5, 95, 14, 90, 84, 91, 8, 35,103, 32, 97, 28, 66,
      102, 31, 26, 45, 75, 4, 85, 92, 37, 74, 80, 49, 68, 29,115, 44,
      64,107,108, 24,110, 83, 36, 78, 42, 19, 15, 41, 88,119, 59, 3 };
  static const u16 S9[512] = {
      167,239,161,379,391,334, 9,338, 38,226, 48,358,452,385, 90,397,
      183,253,147,331,415,340, 51,362,306,500,262, 82,216,159,356,177,
      175,241,489, 37,206, 17, 0,333, 44,254,378, 58,143,220, 81,400,
       95, 3,315,245, 54,235,218,405,472,264,172,494,371,290,399, 76,
      165,197,395,121,257,480,423,212,240, 28,462,176,406,507,288,223,
      501,407,249,265, 89,186,221,428,164, 74,440,196,458,421,350,163,
      232,158,134,354, 13,250,491,142,191, 69,193,425,152,227,366,135,
      344,300,276,242,437,320,113,278, 11,243, 87,317, 36, 93,496, 27,
      487,446,482, 41, 68,156,457,131,326,403,339, 20, 39,115,442,124,
      475,384,508, 53,112,170,479,151,126,169, 73,268,279,321,168,364,
      363,292, 46,499,393,327,324, 24,456,267,157,460,488,426,309,229,
      439,506,208,271,349,401,434,236, 16,209,359, 52, 56,120,199,277,
      465,416,252,287,246, 6, 83,305,420,345,153,502, 65, 61,244,282,
      173,222,418, 67,386,368,261,101,476,291,195,430, 49, 79,166,330,
      280,383,373,128,382,408,155,495,367,388,274,107,459,417, 62,454,
      132,225,203,316,234, 14,301, 91,503,286,424,211,347,307,140,374,
       35,103,125,427, 19,214,453,146,498,314,444,230,256,329,198,285,
       50,116, 78,410, 10,205,510,171,231, 45,139,467, 29, 86,505, 32,
       72, 26,342,150,313,490,431,238,411,325,149,473, 40,119,174,355,
      185,233,389, 71,448,273,372, 55,110,178,322, 12,469,392,369,190,
        1,109,375,137,181, 88, 75,308,260,484, 98,272,370,275,412,111,
      336,318, 4,504,492,259,304, 77,337,435, 21,357,303,332,483, 18,
       47, 85, 25,497,474,289,100,269,296,478,270,106, 31,104,433, 84,
      414,486,394, 96, 99,154,511,148,413,361,409,255,162,215,302,201,
      266,351,343,144,441,365,108,298,251, 34,182,509,138,210,335,133,
      311,352,328,141,396,346,123,319,450,281,429,228,443,481, 92,404,
      485,422,248,297, 23,213,130,466, 22,217,283, 70,294,360,419,127,
      312,377, 7,468,194, 2,117,295,463,258,224,447,247,187, 80,398,
      284,353,105,390,299,471,470,184, 57,200,348, 63,204,188, 33,451,
       97, 30,310,219, 94,160,129,493, 64,179,263,102,189,207,114,402,
      438,477,387,122,192, 42,381, 5,145,118,180,449,293,323,136,380,
       43, 66, 60,455,341,445,202,432, 8,237, 15,376,436,464, 59,461};

  /* The sixteen bit input is split into two unequal halves, *
   * nine bits and seven bits - as is the subkey            */

  nine  = (u16)(in>>7)&0x1FF;
  seven = (u16)(in&0x7F);

  /* Now run the various operations */
  nine   = (u16)(S9[nine] ^ seven);
  seven  = (u16)(S7[seven] ^ (nine & 0x7F));
  seven ^= (subkey>>9);
  nine  ^= (subkey&0x1FF);
  nine   = (u16)(S9[nine] ^ seven);
  seven  = (u16)(S7[seven] ^ (nine & 0x7F));
  return (u16)(seven<<9) + nine;
}

static ulong32 FO( ulong32 in, int round_no, symmetric_key *key)
{
   u16 left, right;

  /* Split the input into two 16-bit words */
  left = (u16)(in>>16);
  right = (u16) in&0xFFFF;

  /* Now apply the same basic transformation three times */
  left ^= key->kasumi.KOi1[round_no];
  left = FI( left, key->kasumi.KIi1[round_no] );
  left ^= right;

  right ^= key->kasumi.KOi2[round_no];
  right = FI( right, key->kasumi.KIi2[round_no] );
  right ^= left;

  left ^= key->kasumi.KOi3[round_no];
  left = FI( left, key->kasumi.KIi3[round_no] );
  left ^= right;

  return (((ulong32)right)<<16)+left;
}

static ulong32 FL( ulong32 in, int round_no, symmetric_key *key )
{
    u16 l, r, a, b;
    /* split out the left and right halves */
    l = (u16)(in>>16);
    r = (u16)(in)&0xFFFF;
    /* do the FL() operations           */
    a = (u16) (l & key->kasumi.KLi1[round_no]);
    r ^= ROL16(a,1);
    b = (u16)(r | key->kasumi.KLi2[round_no]);
    l ^= ROL16(b,1);
    /* put the two halves back together */

    return (((ulong32)l)<<16) + r;
}

int kasumi_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
{
    ulong32 left, right, temp;
    int n;

    LTC_ARGCHK(pt   != NULL);
    LTC_ARGCHK(ct   != NULL);
    LTC_ARGCHK(skey != NULL);

    LOAD32H(left, pt);
    LOAD32H(right, pt+4);

    for (n = 0; n <= 7; ) {     
        temp = FL(left,  n,   skey);
        temp = FO(temp,  n++, skey);
        right ^= temp;
        temp = FO(right, n,   skey);
        temp = FL(temp,  n++, skey);
        left ^= temp;
    }

    STORE32H(left, ct);
    STORE32H(right, ct+4);

    return CRYPT_OK;
}

int kasumi_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
{
    ulong32 left, right, temp;
    int n;

    LTC_ARGCHK(pt   != NULL);
    LTC_ARGCHK(ct   != NULL);
    LTC_ARGCHK(skey != NULL);

    LOAD32H(left, ct);
    LOAD32H(right, ct+4);

    for (n = 7; n >= 0; ) {
        temp = FO(right, n,   skey);
        temp = FL(temp,  n--, skey);
        left ^= temp;
        temp = FL(left,  n,   skey);
        temp = FO(temp,  n--, skey);
        right ^= temp;
    }

    STORE32H(left, pt);
    STORE32H(right, pt+4);

    return CRYPT_OK;
}

int kasumi_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
{
    static const u16 C[8] = { 0x0123,0x4567,0x89AB,0xCDEF, 0xFEDC,0xBA98,0x7654,0x3210 };
    u16 ukey[8], Kprime[8];
    int n;

    LTC_ARGCHK(key  != NULL);
    LTC_ARGCHK(skey != NULL);

    if (keylen != 16) {
       return CRYPT_INVALID_KEYSIZE;
    }

    if (num_rounds != 0 && num_rounds != 8) {
       return CRYPT_INVALID_ROUNDS;
    }

    /* Start by ensuring the subkeys are endian correct on a 16-bit basis */
    for (n = 0; n < 8; n++ ) {
        ukey[n] = (((u16)key[2*n]) << 8) | key[2*n+1];
    }

    /* Now build the K'[] keys */
    for (n = 0; n < 8; n++) {
        Kprime[n] = ukey[n] ^ C[n];
    }

    /* Finally construct the various sub keys */
    for(n = 0; n < 8; n++) {
        skey->kasumi.KLi1[n] = ROL16(ukey[n],1);
        skey->kasumi.KLi2[n] = Kprime[(n+2)&0x7];
        skey->kasumi.KOi1[n] = ROL16(ukey[(n+1)&0x7],5);
        skey->kasumi.KOi2[n] = ROL16(ukey[(n+5)&0x7],8);
        skey->kasumi.KOi3[n] = ROL16(ukey[(n+6)&0x7],13);
        skey->kasumi.KIi1[n] = Kprime[(n+4)&0x7];
        skey->kasumi.KIi2[n] = Kprime[(n+3)&0x7];
        skey->kasumi.KIi3[n] = Kprime[(n+7)&0x7];
    }

    return CRYPT_OK;
}

void kasumi_done(symmetric_key *skey)
{
}

int kasumi_keysize(int *keysize)
{
   LTC_ARGCHK(keysize != NULL);
   if (*keysize >= 16) {
      *keysize = 16;
      return CRYPT_OK;
   } else {
      return CRYPT_INVALID_KEYSIZE;
   }
}

int kasumi_test(void)
{
#ifndef LTC_TEST
   return CRYPT_NOP;
#else
   static const struct {
      unsigned char key[16], pt[8], ct[8];
   } tests[] = {

{
   { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x4B, 0x58, 0xA7, 0x71, 0xAF, 0xC7, 0xE5, 0xE8 }
},

{
   { 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x7E, 0xEF, 0x11, 0x3C, 0x95, 0xBB, 0x5A, 0x77 }
},

{
   { 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x5F, 0x14, 0x06, 0x86, 0xD7, 0xAD, 0x5A, 0x39 },
},

{
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0x2E, 0x14, 0x91, 0xCF, 0x70, 0xAA, 0x46, 0x5D }
},

{
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00 },
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
   { 0xB5, 0x45, 0x86, 0xF4, 0xAB, 0x9A, 0xE5, 0x46 }
},

};
   unsigned char buf[2][8];
   symmetric_key key;
   int err, x;

   for (x = 0; x < (int)(sizeof(tests)/sizeof(tests[0])); x++) {
       if ((err = kasumi_setup(tests[x].key, 16, 0, &key)) != CRYPT_OK) {
          return err;
       }
       if ((err = kasumi_ecb_encrypt(tests[x].pt, buf[0], &key)) != CRYPT_OK) {
          return err;
       }
       if ((err = kasumi_ecb_decrypt(tests[x].ct, buf[1], &key)) != CRYPT_OK) {
          return err;
       }
       if (XMEMCMP(tests[x].pt, buf[1], 8) || XMEMCMP(tests[x].ct, buf[0], 8)) {
          return CRYPT_FAIL_TESTVECTOR;
       }
   }
   return CRYPT_OK;
#endif
}

#endif

/* $Source: /cvs/libtom/libtomcrypt/src/ciphers/kasumi.c,v $ */
/* $Revision: 1.7 $ */
/* $Date: 2006/11/09 03:05:44 $ */