69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
|
|
/* SPDX-License-Identifier: Unlicense */
|
|
|
|
/**
|
|
@file ocb_done_decrypt.c
|
|
OCB implementation, terminate decryption, by Tom St Denis
|
|
*/
|
|
#include "tomcrypt_private.h"
|
|
|
|
#ifdef LTC_OCB_MODE
|
|
|
|
/**
|
|
Terminate a decrypting OCB state
|
|
@param ocb The OCB state
|
|
@param ct The ciphertext (if any)
|
|
@param ctlen The length of the ciphertext (octets)
|
|
@param pt [out] The plaintext
|
|
@param tag The authentication tag (to compare against)
|
|
@param taglen The length of the authentication tag provided
|
|
@param stat [out] The result of the tag comparison
|
|
@return CRYPT_OK if the process was successful regardless if the tag is valid
|
|
*/
|
|
int ocb_done_decrypt(ocb_state *ocb,
|
|
const unsigned char *ct, unsigned long ctlen,
|
|
unsigned char *pt,
|
|
const unsigned char *tag, unsigned long taglen, int *stat)
|
|
{
|
|
int err;
|
|
unsigned char *tagbuf;
|
|
unsigned long tagbuflen;
|
|
|
|
LTC_ARGCHK(ocb != NULL);
|
|
LTC_ARGCHK(pt != NULL);
|
|
LTC_ARGCHK(ct != NULL);
|
|
LTC_ARGCHK(tag != NULL);
|
|
LTC_ARGCHK(stat != NULL);
|
|
|
|
/* default to failed */
|
|
*stat = 0;
|
|
|
|
/* allocate memory */
|
|
tagbuf = XMALLOC(MAXBLOCKSIZE);
|
|
if (tagbuf == NULL) {
|
|
return CRYPT_MEM;
|
|
}
|
|
|
|
tagbuflen = MAXBLOCKSIZE;
|
|
if ((err = s_ocb_done(ocb, ct, ctlen, pt, tagbuf, &tagbuflen, 1)) != CRYPT_OK) {
|
|
goto LBL_ERR;
|
|
}
|
|
|
|
if (taglen <= tagbuflen && XMEM_NEQ(tagbuf, tag, taglen) == 0) {
|
|
*stat = 1;
|
|
}
|
|
|
|
err = CRYPT_OK;
|
|
LBL_ERR:
|
|
#ifdef LTC_CLEAN_STACK
|
|
zeromem(tagbuf, MAXBLOCKSIZE);
|
|
#endif
|
|
|
|
XFREE(tagbuf);
|
|
|
|
return err;
|
|
}
|
|
|
|
#endif
|
|
|