view libtomcrypt/src/ciphers/noekeon.c @ 1790:42745af83b7d

Introduce extra delay before closing unauthenticated sessions To make it harder for attackers, introduce a delay to keep an unauthenticated session open a bit longer, thus blocking a connection slot until after the delay. Without this, while there is a limit on the amount of attempts an attacker can make at the same time (MAX_UNAUTH_PER_IP), the time taken by dropbear to handle one attempt is still short and thus for each of the allowed parallel attempts many attempts can be chained one after the other. The attempt rate is then: "MAX_UNAUTH_PER_IP / <process time of one attempt>". With the delay, this rate becomes: "MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".
author Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
date Wed, 15 Feb 2017 13:53:04 +0100
parents 6dba84798cd5
children
line wrap: on
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.
 */
/**
   @file noekeon.c
   Implementation of the Noekeon block cipher by Tom St Denis
*/
#include "tomcrypt.h"

#ifdef LTC_NOEKEON

const struct ltc_cipher_descriptor noekeon_desc =
{
    "noekeon",
    16,
    16, 16, 16, 16,
    &noekeon_setup,
    &noekeon_ecb_encrypt,
    &noekeon_ecb_decrypt,
    &noekeon_test,
    &noekeon_done,
    &noekeon_keysize,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

static const ulong32 RC[] = {
   0x00000080UL, 0x0000001bUL, 0x00000036UL, 0x0000006cUL,
   0x000000d8UL, 0x000000abUL, 0x0000004dUL, 0x0000009aUL,
   0x0000002fUL, 0x0000005eUL, 0x000000bcUL, 0x00000063UL,
   0x000000c6UL, 0x00000097UL, 0x00000035UL, 0x0000006aUL,
   0x000000d4UL
};

#define kTHETA(a, b, c, d)                                 \
    temp = a^c; temp = temp ^ ROLc(temp, 8) ^ RORc(temp, 8); \
    b ^= temp; d ^= temp;                                  \
    temp = b^d; temp = temp ^ ROLc(temp, 8) ^ RORc(temp, 8); \
    a ^= temp; c ^= temp;

#define THETA(k, a, b, c, d)                               \
    temp = a^c; temp = temp ^ ROLc(temp, 8) ^ RORc(temp, 8); \
    b ^= temp ^ k[1]; d ^= temp ^ k[3];                    \
    temp = b^d; temp = temp ^ ROLc(temp, 8) ^ RORc(temp, 8); \
    a ^= temp ^ k[0]; c ^= temp ^ k[2];

#define GAMMA(a, b, c, d)     \
    b ^= ~(d|c);              \
    a ^= c&b;                 \
    temp = d; d = a; a = temp;\
    c ^= a ^ b ^ d;           \
    b ^= ~(d|c);              \
    a ^= c&b;

#define PI1(a, b, c, d) \
    b = ROLc(b, 1); c = ROLc(c, 5); d = ROLc(d, 2);

#define PI2(a, b, c, d) \
    b = RORc(b, 1); c = RORc(c, 5); d = RORc(d, 2);

 /**
    Initialize the Noekeon 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
 */
int noekeon_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
{
   ulong32 temp;

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

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

   if (num_rounds != 16 && num_rounds != 0) {
      return CRYPT_INVALID_ROUNDS;
   }

   LOAD32H(skey->noekeon.K[0],&key[0]);
   LOAD32H(skey->noekeon.K[1],&key[4]);
   LOAD32H(skey->noekeon.K[2],&key[8]);
   LOAD32H(skey->noekeon.K[3],&key[12]);

   LOAD32H(skey->noekeon.dK[0],&key[0]);
   LOAD32H(skey->noekeon.dK[1],&key[4]);
   LOAD32H(skey->noekeon.dK[2],&key[8]);
   LOAD32H(skey->noekeon.dK[3],&key[12]);

   kTHETA(skey->noekeon.dK[0], skey->noekeon.dK[1], skey->noekeon.dK[2], skey->noekeon.dK[3]);

   return CRYPT_OK;
}

/**
  Encrypts a block of text with Noekeon
  @param pt The input plaintext (16 bytes)
  @param ct The output ciphertext (16 bytes)
  @param skey The key as scheduled
  @return CRYPT_OK if successful
*/
#ifdef LTC_CLEAN_STACK
static int _noekeon_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
#else
int noekeon_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
#endif
{
   ulong32 a,b,c,d,temp;
   int r;

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

   LOAD32H(a,&pt[0]); LOAD32H(b,&pt[4]);
   LOAD32H(c,&pt[8]); LOAD32H(d,&pt[12]);

#define ROUND(i) \
       a ^= RC[i]; \
       THETA(skey->noekeon.K, a,b,c,d); \
       PI1(a,b,c,d); \
       GAMMA(a,b,c,d); \
       PI2(a,b,c,d);

   for (r = 0; r < 16; ++r) {
       ROUND(r);
   }

#undef ROUND

   a ^= RC[16];
   THETA(skey->noekeon.K, a, b, c, d);

   STORE32H(a,&ct[0]); STORE32H(b,&ct[4]);
   STORE32H(c,&ct[8]); STORE32H(d,&ct[12]);

   return CRYPT_OK;
}

#ifdef LTC_CLEAN_STACK
int noekeon_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
{
   int err = _noekeon_ecb_encrypt(pt, ct, skey);
   burn_stack(sizeof(ulong32) * 5 + sizeof(int));
   return err;
}
#endif

/**
  Decrypts a block of text with Noekeon
  @param ct The input ciphertext (16 bytes)
  @param pt The output plaintext (16 bytes)
  @param skey The key as scheduled
  @return CRYPT_OK if successful
*/
#ifdef LTC_CLEAN_STACK
static int _noekeon_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
#else
int noekeon_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
#endif
{
   ulong32 a,b,c,d, temp;
   int r;

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

   LOAD32H(a,&ct[0]); LOAD32H(b,&ct[4]);
   LOAD32H(c,&ct[8]); LOAD32H(d,&ct[12]);


#define ROUND(i) \
       THETA(skey->noekeon.dK, a,b,c,d); \
       a ^= RC[i]; \
       PI1(a,b,c,d); \
       GAMMA(a,b,c,d); \
       PI2(a,b,c,d);

   for (r = 16; r > 0; --r) {
       ROUND(r);
   }

#undef ROUND

   THETA(skey->noekeon.dK, a,b,c,d);
   a ^= RC[0];
   STORE32H(a,&pt[0]); STORE32H(b, &pt[4]);
   STORE32H(c,&pt[8]); STORE32H(d, &pt[12]);
   return CRYPT_OK;
}

#ifdef LTC_CLEAN_STACK
int noekeon_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
{
   int err = _noekeon_ecb_decrypt(ct, pt, skey);
   burn_stack(sizeof(ulong32) * 5 + sizeof(int));
   return err;
}
#endif

/**
  Performs a self-test of the Noekeon block cipher
  @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
*/
int noekeon_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else
 static const struct {
     int keylen;
     unsigned char key[16], pt[16], ct[16];
 } tests[] = {
   {
      16,
      { 0xAA, 0x3C, 0x8C, 0x86, 0xD9, 0x8B, 0xF8, 0xBE, 0x21, 0xE0, 0x36, 0x09, 0x78, 0xFB, 0xE4, 0x90 },
      { 0xE4, 0x96, 0x6C, 0xD3, 0x13, 0xA0, 0x6C, 0xAF, 0xD0, 0x23, 0xC9, 0xFD, 0x45, 0x32, 0x23, 0x16 },
      { 0xA6, 0xEC, 0xB8, 0xA8, 0x61, 0xFD, 0x62, 0xD9, 0x13, 0x02, 0xFE, 0x9E, 0x47, 0x01, 0x3F, 0xC3 }
   },
   {
      16,
      { 0xED, 0x43, 0xD1, 0x87, 0x21, 0x7E, 0xE0, 0x97, 0x3D, 0x76, 0xC3, 0x37, 0x2E, 0x7D, 0xAE, 0xD3 },
      { 0xE3, 0x38, 0x32, 0xCC, 0xF2, 0x2F, 0x2F, 0x0A, 0x4A, 0x8B, 0x8F, 0x18, 0x12, 0x20, 0x17, 0xD3 },
      { 0x94, 0xA5, 0xDF, 0xF5, 0xAE, 0x1C, 0xBB, 0x22, 0xAD, 0xEB, 0xA7, 0x0D, 0xB7, 0x82, 0x90, 0xA0 }
   },
   {
      16,
      { 0x6F, 0xDC, 0x23, 0x38, 0xF2, 0x10, 0xFB, 0xD3, 0xC1, 0x8C, 0x02, 0xF6, 0xB4, 0x6A, 0xD5, 0xA8 },
      { 0xDB, 0x29, 0xED, 0xB5, 0x5F, 0xB3, 0x60, 0x3A, 0x92, 0xA8, 0xEB, 0x9C, 0x6D, 0x9D, 0x3E, 0x8F },
      { 0x78, 0xF3, 0x6F, 0xF8, 0x9E, 0xBB, 0x8C, 0x6A, 0xE8, 0x10, 0xF7, 0x00, 0x22, 0x15, 0x30, 0x3D }
   },
   {
      16,
      { 0x2C, 0x0C, 0x02, 0xEF, 0x6B, 0xC4, 0xF2, 0x0B, 0x2E, 0xB9, 0xE0, 0xBF, 0xD9, 0x36, 0xC2, 0x4E },
      { 0x84, 0xE2, 0xFE, 0x64, 0xB1, 0xB9, 0xFE, 0x76, 0xA8, 0x3F, 0x45, 0xC7, 0x40, 0x7A, 0xAF, 0xEE },
      { 0x2A, 0x08, 0xD6, 0xA2, 0x1C, 0x63, 0x08, 0xB0, 0xF8, 0xBC, 0xB3, 0xA1, 0x66, 0xF7, 0xAE, 0xCF }
   },
   {
      16,
      { 0x6F, 0x30, 0xF8, 0x9F, 0xDA, 0x6E, 0xA0, 0x91, 0x04, 0x0F, 0x6C, 0x8B, 0x7D, 0xF7, 0x2A, 0x4B },
      { 0x65, 0xB6, 0xA6, 0xD0, 0x42, 0x14, 0x08, 0x60, 0x34, 0x8D, 0x37, 0x2F, 0x01, 0xF0, 0x46, 0xBE },
      { 0x66, 0xAC, 0x0B, 0x62, 0x1D, 0x68, 0x11, 0xF5, 0x27, 0xB1, 0x13, 0x5D, 0xF3, 0x2A, 0xE9, 0x18 }
   },
   {
      16,
      { 0xCA, 0xA4, 0x16, 0xB7, 0x1C, 0x92, 0x2E, 0xAD, 0xEB, 0xA7, 0xDB, 0x69, 0x92, 0xCB, 0x35, 0xEF },
      { 0x81, 0x6F, 0x8E, 0x4D, 0x96, 0xC6, 0xB3, 0x67, 0x83, 0xF5, 0x63, 0xC7, 0x20, 0x6D, 0x40, 0x23 },
      { 0x44, 0xF7, 0x63, 0x62, 0xF0, 0x43, 0xBB, 0x67, 0x4A, 0x75, 0x12, 0x42, 0x46, 0x29, 0x28, 0x19 }
   },
   {
      16,
      { 0x6B, 0xCF, 0x22, 0x2F, 0xE0, 0x1B, 0xB0, 0xAA, 0xD8, 0x3C, 0x91, 0x99, 0x18, 0xB2, 0x28, 0xE8 },
      { 0x7C, 0x37, 0xC7, 0xD0, 0xAC, 0x92, 0x29, 0xF1, 0x60, 0x82, 0x93, 0x89, 0xAA, 0x61, 0xAA, 0xA9 },
      { 0xE5, 0x89, 0x1B, 0xB3, 0xFE, 0x8B, 0x0C, 0xA1, 0xA6, 0xC7, 0xBE, 0x12, 0x73, 0x0F, 0xC1, 0x19 }
   },
   {
      16,
      { 0xE6, 0xD0, 0xF1, 0x03, 0x2E, 0xDE, 0x70, 0x8D, 0xD8, 0x9E, 0x36, 0x5C, 0x05, 0x52, 0xE7, 0x0D },
      { 0xE2, 0x42, 0xE7, 0x92, 0x0E, 0xF7, 0x82, 0xA2, 0xB8, 0x21, 0x8D, 0x26, 0xBA, 0x2D, 0xE6, 0x32 },
      { 0x1E, 0xDD, 0x75, 0x22, 0xB9, 0x36, 0x8A, 0x0F, 0x32, 0xFD, 0xD4, 0x48, 0x65, 0x12, 0x5A, 0x2F }
   }
 };
 symmetric_key key;
 unsigned char tmp[2][16];
 int err, i, y;

 for (i = 0; i < (int)(sizeof(tests)/sizeof(tests[0])); i++) {
    zeromem(&key, sizeof(key));
    if ((err = noekeon_setup(tests[i].key, tests[i].keylen, 0, &key)) != CRYPT_OK) {
       return err;
    }

    noekeon_ecb_encrypt(tests[i].pt, tmp[0], &key);
    noekeon_ecb_decrypt(tmp[0], tmp[1], &key);
    if (compare_testvector(tmp[0], 16, tests[i].ct, 16, "Noekeon Encrypt", i) ||
          compare_testvector(tmp[1], 16, tests[i].pt, 16, "Noekeon Decrypt", i)) {
        return CRYPT_FAIL_TESTVECTOR;
    }

    /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
    for (y = 0; y < 16; y++) tmp[0][y] = 0;
    for (y = 0; y < 1000; y++) noekeon_ecb_encrypt(tmp[0], tmp[0], &key);
    for (y = 0; y < 1000; y++) noekeon_ecb_decrypt(tmp[0], tmp[0], &key);
    for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
 }
 return CRYPT_OK;
 #endif
}

/** Terminate the context
   @param skey    The scheduled key
*/
void noekeon_done(symmetric_key *skey)
{
  LTC_UNUSED_PARAM(skey);
}

/**
  Gets suitable key size
  @param keysize [in/out] The length of the recommended key (in bytes).  This function will store the suitable size back in this variable.
  @return CRYPT_OK if the input key size is acceptable.
*/
int noekeon_keysize(int *keysize)
{
   LTC_ARGCHK(keysize != NULL);
   if (*keysize < 16) {
      return CRYPT_INVALID_KEYSIZE;
   } else {
      *keysize = 16;
      return CRYPT_OK;
   }
}

#endif


/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */