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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
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9 * Tom St Denis, [email protected], http://libtomcrypt.org |
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10 */ |
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11 #include "mycrypt.h" |
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12 |
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13 #ifdef CFB |
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14 |
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15 int cfb_start(int cipher, const unsigned char *IV, const unsigned char *key, |
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16 int keylen, int num_rounds, symmetric_CFB *cfb) |
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17 { |
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18 int x, err; |
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19 |
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20 _ARGCHK(IV != NULL); |
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21 _ARGCHK(key != NULL); |
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22 _ARGCHK(cfb != NULL); |
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23 |
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24 if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { |
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25 return err; |
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26 } |
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27 |
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28 |
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29 /* copy data */ |
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30 cfb->cipher = cipher; |
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31 cfb->blocklen = cipher_descriptor[cipher].block_length; |
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32 for (x = 0; x < cfb->blocklen; x++) |
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33 cfb->IV[x] = IV[x]; |
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34 |
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35 /* init the cipher */ |
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36 if ((err = cipher_descriptor[cipher].setup(key, keylen, num_rounds, &cfb->key)) != CRYPT_OK) { |
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37 return err; |
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38 } |
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39 |
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40 /* encrypt the IV */ |
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41 cipher_descriptor[cfb->cipher].ecb_encrypt(cfb->IV, cfb->IV, &cfb->key); |
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42 cfb->padlen = 0; |
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43 |
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44 return CRYPT_OK; |
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45 } |
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46 |
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47 #endif |
