annotate src/modes/cfb/cfb_start.c @ 381:999a5eb4ed10 libtomcrypt-dropbear

propagate from branch 'au.asn.ucc.matt.ltc.orig' (head 52840647ac7f5c707c3bd158d119a15734a7ef28) to branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 02:39:21 +0000
parents d5faf4814ddb
children
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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.com
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10 */
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11 #include "tomcrypt.h"
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12
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13 /**
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14 @file cfb_start.c
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15 CFB implementation, start chain, Tom St Denis
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16 */
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17
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18
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19 #ifdef LTC_CFB_MODE
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20
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21 /**
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22 Initialize a CFB context
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23 @param cipher The index of the cipher desired
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24 @param IV The initial vector
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25 @param key The secret key
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26 @param keylen The length of the secret key (octets)
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27 @param num_rounds Number of rounds in the cipher desired (0 for default)
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28 @param cfb The CFB state to initialize
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29 @return CRYPT_OK if successful
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30 */
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31 int cfb_start(int cipher, const unsigned char *IV, const unsigned char *key,
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32 int keylen, int num_rounds, symmetric_CFB *cfb)
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33 {
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34 int x, err;
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35
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36 LTC_ARGCHK(IV != NULL);
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37 LTC_ARGCHK(key != NULL);
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38 LTC_ARGCHK(cfb != NULL);
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39
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40 if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
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41 return err;
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42 }
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43
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44
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45 /* copy data */
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46 cfb->cipher = cipher;
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47 cfb->blocklen = cipher_descriptor[cipher].block_length;
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48 for (x = 0; x < cfb->blocklen; x++)
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49 cfb->IV[x] = IV[x];
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50
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51 /* init the cipher */
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52 if ((err = cipher_descriptor[cipher].setup(key, keylen, num_rounds, &cfb->key)) != CRYPT_OK) {
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53 return err;
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54 }
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55
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56 /* encrypt the IV */
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57 cfb->padlen = 0;
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58 return cipher_descriptor[cfb->cipher].ecb_encrypt(cfb->IV, cfb->IV, &cfb->key);
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59 }
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60
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61 #endif
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62
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63 /* $Source: /cvs/libtom/libtomcrypt/src/modes/cfb/cfb_start.c,v $ */
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64 /* $Revision: 1.6 $ */
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65 /* $Date: 2006/06/29 01:51:34 $ */