42 lines
1.1 KiB
C
42 lines
1.1 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 OFB
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int ofb_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_OFB *ofb)
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{
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int err;
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_ARGCHK(pt != NULL);
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_ARGCHK(ct != NULL);
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_ARGCHK(ofb != NULL);
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if ((err = cipher_is_valid(ofb->cipher)) != CRYPT_OK) {
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return err;
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}
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/* is blocklen/padlen valid? */
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if (ofb->blocklen < 0 || ofb->blocklen > (int)sizeof(ofb->IV) ||
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ofb->padlen < 0 || ofb->padlen > (int)sizeof(ofb->IV)) {
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return CRYPT_INVALID_ARG;
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}
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while (len-- > 0) {
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if (ofb->padlen == ofb->blocklen) {
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cipher_descriptor[ofb->cipher].ecb_encrypt(ofb->IV, ofb->IV, &ofb->key);
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ofb->padlen = 0;
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}
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*ct++ = *pt++ ^ ofb->IV[ofb->padlen++];
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}
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return CRYPT_OK;
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}
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#endif
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