serpent.c

开源的目录加密软件

    skey->serpent.K[4 * (r) + 1] = b; \
    skey->serpent.K[4 * (r) + 2] = c; \
    skey->serpent.K[4 * (r) + 3] = d

/* the linear transformation and its inverse    */

#define rot(a,b,c,d)    \
    a = ROL(a, 13);    \
    c = ROL(c, 3);     \
    d ^= c ^ (a << 3);  \
    b ^= a ^ c;         \
    d = ROL(d, 7);     \
    b = ROL(b, 1);     \
    a ^= b ^ d;         \
    c ^= d ^ (b << 7);  \
    a = ROL(a, 5);     \
    c = ROL(c, 22)

#define irot(a,b,c,d)   \
    c = ROR(c, 22);    \
    a = ROR(a, 5);     \
    c ^= d ^ (b << 7);  \
    a ^= b ^ d;         \
    d = ROR(d, 7);     \
    b = ROR(b, 1);     \
    d ^= c ^ (a << 3);  \
    b ^= a ^ c;         \
    c = ROR(c, 3);     \
    a = ROR(a, 13)

/**
  Initialize the Serpent 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 _serpent_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
#else
int serpent_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
#endif
{
    unsigned long lkey[140], t, a, b, c, d, e, f, g, h, x;
    unsigned long t1,t2,t3,t4,t5,t6,t7,t8,t9,t10,t11,t12,t13,t14,t15,t16;
    unsigned char buf[32];

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

    /* check rounds */
    if (num_rounds != 0 && num_rounds != 32) {
       return CRYPT_INVALID_ROUNDS;
    }

    /* check keylen */
    if (keylen < 16 || keylen > 32) {
       return CRYPT_INVALID_KEYSIZE;
    }

    /* copy key and expand to 32bytes as required */
    for (x = 0; x < (unsigned long)keylen; x++) {
        buf[x] = key[x];
    }

    if (x < 32) {
       buf[x++] = (unsigned char)0x01;
       while (x < 32) {
           buf[x++] = (unsigned char)0;
       }
    }

    /* copy key into 32-bit words */
    for (x = 0; x < 8; x++) {
        LOAD32L(lkey[x], &buf[x*4]);
    }

    /* expand using the LFSR to 140 words */
    for (x = 0; x < 132; x++) {
        t = lkey[x] ^ lkey[x+3] ^ lkey[x+5] ^ lkey[x+7] ^ x ^ 0x9E3779B9UL;
        lkey[x + 8] = ROL(t, 11);
    }

    /* perform the substituions */
    for (x = 0; x < 32; ) {
       k_set( x,a,b,c,d);sb3(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb2(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb1(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb0(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb7(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb6(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb5(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
       k_set( x,a,b,c,d);sb4(a,b,c,d,e,f,g,h);k_get( x,e,f,g,h); ++x;
    }
    k_set(32,a,b,c,d);sb3(a,b,c,d,e,f,g,h);k_get(32,e,f,g,h);
    return CRYPT_OK;
}

#ifdef LTC_CLEAN_STACK
int serpent_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
{
   int x;
   x = _serpent_setup(key, keylen, num_rounds, skey);
   burn_stack(sizeof(unsigned long)*166 + sizeof(unsigned char)*32);
   return x;
}
#endif

/**
  Encrypts a block of text with Serpent
  @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 _serpent_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
#else
int serpent_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
#endif
{
    unsigned long a,b,c,d,e,f,g,h;
    unsigned long t1,t2,t3,t4,t5,t6,t7,t8,t9,t10,t11,t12,t13,t14,t15,t16;

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

    LOAD32L(a, &pt[0]);LOAD32L(b, &pt[4]);LOAD32L(c, &pt[8]);LOAD32L(d, &pt[12]);
    k_xor( 0,a,b,c,d); sb0(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor( 1,e,f,g,h); sb1(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor( 2,a,b,c,d); sb2(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor( 3,e,f,g,h); sb3(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor( 4,a,b,c,d); sb4(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor( 5,e,f,g,h); sb5(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor( 6,a,b,c,d); sb6(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor( 7,e,f,g,h); sb7(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor( 8,a,b,c,d); sb0(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor( 9,e,f,g,h); sb1(e,f,g,h,a,b,c,d); rot(a,b,c,d); 
    k_xor(10,a,b,c,d); sb2(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(11,e,f,g,h); sb3(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(12,a,b,c,d); sb4(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(13,e,f,g,h); sb5(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(14,a,b,c,d); sb6(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(15,e,f,g,h); sb7(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(16,a,b,c,d); sb0(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(17,e,f,g,h); sb1(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(18,a,b,c,d); sb2(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(19,e,f,g,h); sb3(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(20,a,b,c,d); sb4(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(21,e,f,g,h); sb5(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(22,a,b,c,d); sb6(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(23,e,f,g,h); sb7(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(24,a,b,c,d); sb0(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(25,e,f,g,h); sb1(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(26,a,b,c,d); sb2(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(27,e,f,g,h); sb3(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(28,a,b,c,d); sb4(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(29,e,f,g,h); sb5(e,f,g,h,a,b,c,d); rot(a,b,c,d);
    k_xor(30,a,b,c,d); sb6(a,b,c,d,e,f,g,h); rot(e,f,g,h);
    k_xor(31,e,f,g,h); sb7(e,f,g,h,a,b,c,d); k_xor(32,a,b,c,d);
    STORE32L(a, &ct[0]);STORE32L(b, &ct[4]);STORE32L(c, &ct[8]);STORE32L(d, &ct[12]);

	return CRYPT_OK;
}

#ifdef LTC_CLEAN_STACK
int serpent_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
{
   int err = _serpent_ecb_encrypt(pt, ct, skey);
   burn_stack(sizeof(unsigned long)*24);
   return err;
}
#endif


/**
  Decrypts a block of text with Serpent
  @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 _serpent_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
#else
int serpent_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
#endif
{
    unsigned long a,b,c,d,e,f,g,h;
    unsigned long t1,t2,t3,t4,t5,t6,t7,t8,t9,t10,t11,t12,t13,t14,t15,t16;

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

    LOAD32L(a, &ct[0]);LOAD32L(b, &ct[4]);LOAD32L(c, &ct[8]);LOAD32L(d, &ct[12]);
    k_xor(32,a,b,c,d); ib7(a,b,c,d,e,f,g,h); k_xor(31,e,f,g,h);
    irot(e,f,g,h); ib6(e,f,g,h,a,b,c,d); k_xor(30,a,b,c,d);
    irot(a,b,c,d); ib5(a,b,c,d,e,f,g,h); k_xor(29,e,f,g,h);
    irot(e,f,g,h); ib4(e,f,g,h,a,b,c,d); k_xor(28,a,b,c,d);
    irot(a,b,c,d); ib3(a,b,c,d,e,f,g,h); k_xor(27,e,f,g,h);
    irot(e,f,g,h); ib2(e,f,g,h,a,b,c,d); k_xor(26,a,b,c,d);
    irot(a,b,c,d); ib1(a,b,c,d,e,f,g,h); k_xor(25,e,f,g,h);
    irot(e,f,g,h); ib0(e,f,g,h,a,b,c,d); k_xor(24,a,b,c,d);
    irot(a,b,c,d); ib7(a,b,c,d,e,f,g,h); k_xor(23,e,f,g,h);
    irot(e,f,g,h); ib6(e,f,g,h,a,b,c,d); k_xor(22,a,b,c,d);
    irot(a,b,c,d); ib5(a,b,c,d,e,f,g,h); k_xor(21,e,f,g,h);
    irot(e,f,g,h); ib4(e,f,g,h,a,b,c,d); k_xor(20,a,b,c,d);
    irot(a,b,c,d); ib3(a,b,c,d,e,f,g,h); k_xor(19,e,f,g,h);
    irot(e,f,g,h); ib2(e,f,g,h,a,b,c,d); k_xor(18,a,b,c,d);
    irot(a,b,c,d); ib1(a,b,c,d,e,f,g,h); k_xor(17,e,f,g,h);
    irot(e,f,g,h); ib0(e,f,g,h,a,b,c,d); k_xor(16,a,b,c,d);
    irot(a,b,c,d); ib7(a,b,c,d,e,f,g,h); k_xor(15,e,f,g,h);
    irot(e,f,g,h); ib6(e,f,g,h,a,b,c,d); k_xor(14,a,b,c,d);
    irot(a,b,c,d); ib5(a,b,c,d,e,f,g,h); k_xor(13,e,f,g,h);
    irot(e,f,g,h); ib4(e,f,g,h,a,b,c,d); k_xor(12,a,b,c,d);
    irot(a,b,c,d); ib3(a,b,c,d,e,f,g,h); k_xor(11,e,f,g,h);
    irot(e,f,g,h); ib2(e,f,g,h,a,b,c,d); k_xor(10,a,b,c,d);
    irot(a,b,c,d); ib1(a,b,c,d,e,f,g,h); k_xor( 9,e,f,g,h);
    irot(e,f,g,h); ib0(e,f,g,h,a,b,c,d); k_xor( 8,a,b,c,d);
    irot(a,b,c,d); ib7(a,b,c,d,e,f,g,h); k_xor( 7,e,f,g,h);
    irot(e,f,g,h); ib6(e,f,g,h,a,b,c,d); k_xor( 6,a,b,c,d);
    irot(a,b,c,d); ib5(a,b,c,d,e,f,g,h); k_xor( 5,e,f,g,h);
    irot(e,f,g,h); ib4(e,f,g,h,a,b,c,d); k_xor( 4,a,b,c,d);
    irot(a,b,c,d); ib3(a,b,c,d,e,f,g,h); k_xor( 3,e,f,g,h);
    irot(e,f,g,h); ib2(e,f,g,h,a,b,c,d); k_xor( 2,a,b,c,d);
    irot(a,b,c,d); ib1(a,b,c,d,e,f,g,h); k_xor( 1,e,f,g,h);
    irot(e,f,g,h); ib0(e,f,g,h,a,b,c,d); k_xor( 0,a,b,c,d);
    STORE32L(a, &pt[0]);STORE32L(b, &pt[4]);STORE32L(c, &pt[8]);STORE32L(d, &pt[12]);

	return CRYPT_OK;
}

#ifdef LTC_CLEAN_STACK
int serpent_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
{
   int err = _serpent_ecb_decrypt(ct, pt, skey);
   burn_stack(sizeof(unsigned long)*24);
   return err;
}
#endif

/**
  Performs a self-test of the Twofish block cipher
  @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
*/
int serpent_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else    
   static const struct {
       int keylen;
       unsigned char key[32], pt[16], ct[16];
   } tests[] = {
   {
      16,
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0xdd, 0xd2, 0x6b, 0x98, 0xa5, 0xff, 0xd8, 0x2c,
        0x05, 0x34, 0x5a, 0x9d, 0xad, 0xbf, 0xaf, 0x49 }
   },
   {
      16,
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80 },
      { 0x4a, 0xe9, 0xa2, 0x0b, 0x2b, 0x14, 0xa1, 0x02,
        0x90, 0xcb, 0xb8, 0x20, 0xb7, 0xff, 0xb5, 0x10 }
   },
   {
      24,
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08 },
      { 0xe1, 0x1b, 0x01, 0x52, 0x4e, 0xa1, 0xf4, 0x65, 
        0xa2, 0xa2, 0x00, 0x43, 0xeb, 0x9f, 0x7e, 0x8a }
   },
   {
      32,
      { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0xe0, 0x88, 0x5d, 0x44, 0x60, 0x37, 0x34, 0x69,
        0xd1, 0xfa, 0x6c, 0x36, 0xa6, 0xe1, 0xc5, 0x2f }
   },
   {
      32,
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x17, 0xc6, 0x25, 0x8e, 0x60, 0x09, 0xe2, 0x82,
        0x66, 0x18, 0x69, 0xd5, 0x25, 0xf7, 0xd2, 0x04 }
   },
   {
      32,
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      { 0x9f, 0xe1, 0x43, 0x25, 0x0d, 0x00, 0xe2, 0x56, 
        0x96, 0xb0, 0x1e, 0x0a, 0x2e, 0xd0, 0x5d, 0xb3 }
   }
   };

   unsigned char buf[2][16];
   int x, err;
   symmetric_key key;

   for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
      /* setup key */
      if ((err = serpent_setup(tests[x].key, tests[x].keylen, 0, &key))!= CRYPT_OK) {
         return err;
      }

      /* encrypt and decrypt */
      serpent_ecb_encrypt(tests[x].pt, buf[0], &key);
      serpent_ecb_decrypt(buf[0], buf[1], &key);

      /* compare */
      if (memcmp(buf[0], tests[x].ct, 16) != 0 || memcmp(buf[1], tests[x].pt, 16) != 0) {
         return CRYPT_FAIL_TESTVECTOR;
      }
   }
   return CRYPT_OK;
  #endif
}

/** Terminate the context 
   @param skey    The scheduled key
*/
void serpent_done(symmetric_key *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 serpent_keysize(int *keysize)
{
   LTC_ARGCHK(keysize != NULL);

   if (*keysize < 16)
      return CRYPT_INVALID_KEYSIZE;
   if (*keysize > 32)
      *keysize = 32;
   return CRYPT_OK;
}

#endif