81 lines
1.8 KiB
C
81 lines
1.8 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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/* EAX Implementation by Tom St Denis */
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#include "mycrypt.h"
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#ifdef EAX_MODE
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int eax_decrypt_verify_memory(int cipher,
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const unsigned char *key, unsigned long keylen,
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const unsigned char *nonce, unsigned long noncelen,
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const unsigned char *header, unsigned long headerlen,
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const unsigned char *ct, unsigned long ctlen,
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unsigned char *pt,
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unsigned char *tag, unsigned long taglen,
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int *res)
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{
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int err;
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eax_state *eax;
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unsigned char *buf;
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unsigned long buflen;
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_ARGCHK(res != NULL);
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/* default to zero */
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*res = 0;
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/* allocate ram */
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buf = XMALLOC(taglen);
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eax = XMALLOC(sizeof(eax_state));
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if (eax == NULL || buf == NULL) {
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if (eax != NULL) {
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XFREE(eax);
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}
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if (buf != NULL) {
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XFREE(buf);
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}
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return CRYPT_MEM;
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}
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if ((err = eax_init(eax, cipher, key, keylen, nonce, noncelen, header, headerlen)) != CRYPT_OK) {
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goto __ERR;
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}
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if ((err = eax_decrypt(eax, ct, pt, ctlen)) != CRYPT_OK) {
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goto __ERR;
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}
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buflen = taglen;
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if ((err = eax_done(eax, buf, &buflen)) != CRYPT_OK) {
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goto __ERR;
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}
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/* compare tags */
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if (buflen >= taglen && memcmp(buf, tag, taglen) == 0) {
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*res = 1;
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}
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err = CRYPT_OK;
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__ERR:
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#ifdef CLEAN_STACK
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zeromem(buf, taglen);
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zeromem(eax, sizeof(eax_state));
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#endif
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XFREE(eax);
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XFREE(buf);
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return err;
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}
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#endif
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