/* Implementation of the Noekeon block cipher by Tom St Denis */
#include "mycrypt.h"

#ifdef NOEKEON

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

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 ^ ROL(temp, 8) ^ ROR(temp, 8); \
    b ^= temp; d ^= temp;                                  \
    temp = b^d; temp = temp ^ ROL(temp, 8) ^ ROR(temp, 8); \
    a ^= temp; c ^= temp;

#define THETA(k, a, b, c, d)                               \
    temp = a^c; temp = temp ^ ROL(temp, 8) ^ ROR(temp, 8); \
    b ^= temp; d ^= temp;                                  \
    a ^= k[0]; b ^= k[1];                                  \
    c ^= k[2]; d ^= k[3];                                  \
    temp = b^d; temp = temp ^ ROL(temp, 8) ^ ROR(temp, 8); \
    a ^= temp; c ^= temp;
    
#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) \
    a = ROL(a, 1); c = ROL(c, 5); d = ROL(d, 2);
    
#define PI2(a, b, c, d) \
    a = ROR(a, 1); c = ROR(c, 5); d = ROR(d, 2);
    
int noekeon_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
{
   ulong32 temp;
   
   _ARGCHK(key != NULL);
   _ARGCHK(skey != NULL);
   
   if (keylen != 16) {
      return CRYPT_INVALID_KEYSIZE;
   }
   
   if (num_rounds != 16 && num_rounds != 0) {
      return CRYPT_INVALID_ROUNDS;
   }
   
   LOAD32L(skey->noekeon.K[0],&key[0]);
   LOAD32L(skey->noekeon.K[1],&key[4]);
   LOAD32L(skey->noekeon.K[2],&key[8]);
   LOAD32L(skey->noekeon.K[3],&key[12]);
   
   LOAD32L(skey->noekeon.dK[0],&key[0]);
   LOAD32L(skey->noekeon.dK[1],&key[4]);
   LOAD32L(skey->noekeon.dK[2],&key[8]);
   LOAD32L(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;
}

#ifdef CLEAN_STACK
static void _noekeon_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
#else
void noekeon_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
#endif
{
   ulong32 a,b,c,d,temp;
   int r;

   _ARGCHK(key != NULL);
   _ARGCHK(pt != NULL);
   _ARGCHK(ct != NULL);
   
   LOAD32L(a,&pt[0]); LOAD32L(b,&pt[4]);
   LOAD32L(c,&pt[8]); LOAD32L(d,&pt[12]);
   
#define ROUND(i) \
       a ^= RC[r+i]; \
       THETA(key->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 += 2) {
       ROUND(0);
       ROUND(1);
   }

#undef ROUND

   a ^= RC[16];
   THETA(key->noekeon.K, a, b, c, d);
   
   STORE32L(a,&ct[0]); STORE32L(b,&ct[4]);
   STORE32L(c,&ct[8]); STORE32L(d,&ct[12]);
}

#ifdef CLEAN_STACK
void noekeon_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
{
   _noekeon_ecb_encrypt(pt, ct, key);
   burn_stack(sizeof(ulong32) * 5 + sizeof(int));
}
#endif

#ifdef CLEAN_STACK
static void _noekeon_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
#else
void noekeon_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
#endif
{
   ulong32 a,b,c,d, temp;
   int r;

   _ARGCHK(key != NULL);
   _ARGCHK(pt != NULL);
   _ARGCHK(ct != NULL);
   
   LOAD32L(a,&ct[0]); LOAD32L(b,&ct[4]);
   LOAD32L(c,&ct[8]); LOAD32L(d,&ct[12]);
   
#define ROUND(i) \
       THETA(key->noekeon.dK, a,b,c,d); \
       a ^= RC[r-i]; \
       PI1(a,b,c,d); \
       GAMMA(a,b,c,d); \
       PI2(a,b,c,d); 
       

   for (r = 16; r > 0; r -= 2) {
       ROUND(0);
       ROUND(1);
   }
   
#undef ROUND

   THETA(key->noekeon.dK, a,b,c,d);
   a ^= RC[0];
   STORE32L(a,&pt[0]); STORE32L(b, &pt[4]);
   STORE32L(c,&pt[8]); STORE32L(d, &pt[12]);
}

#ifdef CLEAN_STACK
void noekeon_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
{
   _noekeon_ecb_decrypt(ct, pt, key);
   burn_stack(sizeof(ulong32) * 5 + sizeof(int));
}
#endif

int noekeon_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else    
   static const unsigned char
          key[] = 
             { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
          pt[] = 
             { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
          ct[] = 
             { 0x57, 0x9a, 0x6c, 0xe8, 0x91, 0x16, 0x52, 0x53,
               0x32, 0x00, 0xca, 0x0a, 0x17, 0x5d, 0x28, 0x0e };
   unsigned char tmp[2][16];
   int err;
   symmetric_key skey;
   
   if ((err = noekeon_setup(key, 16, 0, &skey)) != CRYPT_OK) {
      return err;
   }
   
   noekeon_ecb_encrypt(pt, tmp[0], &skey);
   noekeon_ecb_decrypt(tmp[0], tmp[1], &skey);
   
   if (memcmp(tmp[0], ct, 16) != 0 || memcmp(tmp[1], pt, 16) != 0) {
      return CRYPT_FAIL_TESTVECTOR;
   }
   
   return CRYPT_OK;
 #endif
}

int noekeon_keysize(int *desired_keysize)
{
   _ARGCHK(desired_keysize != NULL);
   if (*desired_keysize < 16) {
      return CRYPT_INVALID_KEYSIZE;
   } else {
      *desired_keysize = 16;
      return CRYPT_OK;
   }
}

#endif