TWOFISH *TwoFishInit(const char *userkey)
{ TWOFISH *tfdata;
int i,x,m;
char tkey[TwoFish_KEY_LENGTH+40];
tfdata=malloc(sizeof(TWOFISH)); /* allocate the TwoFish structure */
if(tfdata!=NULL)
{ if(*userkey)
{ strncpy(tkey,userkey,TwoFish_KEY_LENGTH); /* use first 32 chars of user supplied password */
tkey[TwoFish_KEY_LENGTH]=0; /* make sure it wasn't more */
}
else
strcpy(tkey,TwoFish_DEFAULT_PW); /* if no key defined, use default password */
for(i=0,x=0,m=strlen(tkey);i<TwoFish_KEY_LENGTH;i++) /* copy into data structure */
{ tfdata->key[i]=tkey[x++]; /* fill the whole keyspace with repeating key. */
if(x==m)
x=0;
}
if(!TwoFish_MDSready)
_TwoFish_PrecomputeMDSmatrix(); /* "Wake Up, Neo" */
_TwoFish_MakeSubKeys(tfdata); /* generate subkeys */
_TwoFish_ResetCBC(tfdata); /* reset the CBC */
tfdata->output=NULL; /* nothing to output yet */
tfdata->dontflush=FALSE; /* reset decrypt skip block flag */
if(TwoFish_srand)
{ TwoFish_srand=FALSE;
srand(time(NULL));
}
}
return tfdata; /* return the data pointer */
}
unsigned long TwoFishDecryptRaw(const char *in,
char *out,
unsigned long len,
TWOFISH *tfdata)
{ _TwoFish_ResetCBC(tfdata); /* reset CBC flag. */
tfdata->output=(unsigned char*)out; /* output straight into output buffer. */
return _TwoFish_CryptRaw(in,out,len,TRUE,tfdata); /* and go for it. */
}
/* TwoFish Raw Decryption
*
* Does not use header, but does use CBC (if more than one block has to be decrypted).
*
* Input: Pointer to the buffer of the ciphertext to be decrypted.
* Pointer to the buffer receiving the plaintext.
* The length of the ciphertext buffer (at least one cipher block).
* The TwoFish structure.
*
* Output: The amount of bytes decrypted if successful, otherwise 0.
*/
uint32_t TwoFishDecryptRaw(uint8_t *in,
uint8_t *out,
uint32_t len,
TWOFISH *tfdata)
{
_TwoFish_ResetCBC(tfdata); /* reset CBC flag. */
tfdata->output = out; /* output straight into output buffer. */
return _TwoFish_CryptRaw(in, out, len, TRUE, tfdata); /* and go for it. */
}
/* TwoFish Initialization
*
* This routine generates a global data structure for use with TwoFish,
* initializes important values (such as subkeys, sBoxes), generates subkeys
* and precomputes the MDS matrix if not already done.
*
* Input: User supplied password (will be appended by default password of 'SnortHas2FishEncryptionRoutines!')
*
* Output: Pointer to TWOFISH structure. This data structure contains key dependent data.
* This pointer is used with all other crypt functions.
*/
TWOFISH *TwoFishInit(const uint8_t *userkey, uint32_t keysize)
{
TWOFISH *tfdata;
int i, x, m;
uint8_t tkey[TwoFish_KEY_LENGTH + 40];
memset( tkey, 0, TwoFish_KEY_LENGTH + 40 );
tfdata = (TWOFISH *)malloc(sizeof(TWOFISH)); /* allocate the TwoFish structure */
if (tfdata != NULL) {
/* Changes here prevented a dangerous random key segment for keys of length < TwoFish_KEY_LENGTH */
if (keysize > 0) {
memcpy( tkey, userkey, keysize ); /* The rest will be zeros */
} else {
memcpy( tkey, TwoFish_DEFAULT_PW, TwoFish_DEFAULT_PW_LEN ); /* if no key defined, use default password */
}
/* This loop is awful - surely a loop on memcpy() would be clearer and more efficient */
for (i = 0, x = 0, m = keysize; i < TwoFish_KEY_LENGTH; i++) { /* copy into data structure */
tfdata->key[i] = tkey[x++]; /* fill the whole keyspace with repeating key. */
if (x == m)
x = 0;
}
if (!TwoFish_MDSready)
_TwoFish_PrecomputeMDSmatrix(); /* "Wake Up, Neo" */
_TwoFish_MakeSubKeys(tfdata); /* generate subkeys */
_TwoFish_ResetCBC(tfdata); /* reset the CBC */
tfdata->output = NULL; /* nothing to output yet */
tfdata->dontflush = FALSE; /* reset decrypt skip block flag */
if (TwoFish_srand) {
TwoFish_srand = FALSE;
/* REVISIT: BbMaj7 : Should choose something with less predictability
* particularly for embedded targets with no real-time clock. */
srand((unsigned int)time(NULL));
}
}
return tfdata; /* return the data pointer */
}
