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      1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
      2  *
      3  * LibTomCrypt is a library that provides various cryptographic
      4  * algorithms in a highly modular and flexible manner.
      5  *
      6  * The library is free for all purposes without any express
      7  * guarantee it works.
      8  *
      9  * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com
     10  */
     11 #include "tomcrypt.h"
     12 
     13 /**
     14   @file f9_init.c
     15   F9 Support, start an F9 state
     16 */
     17 
     18 #ifdef LTC_F9_MODE
     19 
     20 /** Initialize F9-MAC state
     21   @param f9    [out] f9 state to initialize
     22   @param cipher  Index of cipher to use
     23   @param key     [in]  Secret key
     24   @param keylen  Length of secret key in octets
     25   Return CRYPT_OK on success
     26 */
     27 int f9_init(f9_state *f9, int cipher, const unsigned char *key, unsigned long keylen)
     28 {
     29    int            x, err;
     30 
     31    LTC_ARGCHK(f9   != NULL);
     32    LTC_ARGCHK(key  != NULL);
     33 
     34    /* schedule the key */
     35    if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
     36       return err;
     37    }
     38 
     39 #ifdef LTC_FAST
     40    if (cipher_descriptor[cipher].block_length % sizeof(LTC_FAST_TYPE)) {
     41        return CRYPT_INVALID_ARG;
     42    }
     43 #endif
     44 
     45    if ((err = cipher_descriptor[cipher].setup(key, keylen, 0, &f9->key)) != CRYPT_OK) {
     46       goto done;
     47    }
     48 
     49    /* make the second key */
     50    for (x = 0; (unsigned)x < keylen; x++) {
     51       f9->akey[x] = key[x] ^ 0xAA;
     52    }
     53 
     54    /* setup struct */
     55    zeromem(f9->IV,  cipher_descriptor[cipher].block_length);
     56    zeromem(f9->ACC, cipher_descriptor[cipher].block_length);
     57    f9->blocksize = cipher_descriptor[cipher].block_length;
     58    f9->cipher    = cipher;
     59    f9->buflen    = 0;
     60    f9->keylen    = keylen;
     61 done:
     62    return err;
     63 }
     64 
     65 #endif
     66 
     67 /* $Source: /cvs/libtom/libtomcrypt/src/mac/f9/f9_init.c,v $ */
     68 /* $Revision: 1.4 $ */
     69 /* $Date: 2006/11/08 22:54:18 $ */
     70 
     71