53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
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*/
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#include "mycrypt.h"
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#ifdef CBC
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int cbc_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_CBC *cbc)
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{
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int x, err;
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unsigned char tmp[MAXBLOCKSIZE];
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_ARGCHK(pt != NULL);
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_ARGCHK(ct != NULL);
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_ARGCHK(cbc != NULL);
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if ((err = cipher_is_valid(cbc->cipher)) != CRYPT_OK) {
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return err;
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}
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/* is blocklen valid? */
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if (cbc->blocklen < 0 || cbc->blocklen > (int)sizeof(cbc->IV)) {
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return CRYPT_INVALID_ARG;
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}
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/* xor IV against plaintext */
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for (x = 0; x < cbc->blocklen; x++) {
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tmp[x] = pt[x] ^ cbc->IV[x];
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}
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/* encrypt */
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cipher_descriptor[cbc->cipher].ecb_encrypt(tmp, ct, &cbc->key);
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/* store IV [ciphertext] for a future block */
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for (x = 0; x < cbc->blocklen; x++) {
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cbc->IV[x] = ct[x];
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}
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#ifdef CLEAN_STACK
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zeromem(tmp, sizeof(tmp));
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#endif
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return CRYPT_OK;
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}
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#endif
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