/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*/
/**
@file ocb3_add_aad.c
OCB implementation, add AAD data, by Karel Miko
*/
#include "tomcrypt.h"
#ifdef LTC_OCB3_MODE
/**
Add AAD - additional associated data
@param ocb The OCB state
@param aad The AAD data
@param aadlen The size of AAD data (octets)
@return CRYPT_OK if successful
*/
int ocb3_add_aad(ocb3_state *ocb, const unsigned char *aad, unsigned long aadlen)
{
int err, x, full_blocks, full_blocks_len, last_block_len;
unsigned char *data;
unsigned long datalen, l;
LTC_ARGCHK(ocb != NULL);
LTC_ARGCHK(aad != NULL);
if (aadlen == 0) return CRYPT_OK;
if (ocb->adata_buffer_bytes > 0) {
l = ocb->block_len - ocb->adata_buffer_bytes;
if (l > aadlen) l = aadlen;
XMEMCPY(ocb->adata_buffer+ocb->adata_buffer_bytes, aad, l);
ocb->adata_buffer_bytes += l;
if (ocb->adata_buffer_bytes == ocb->block_len) {
if ((err = ocb3_int_aad_add_block(ocb, ocb->adata_buffer)) != CRYPT_OK) {
return err;
}
ocb->adata_buffer_bytes = 0;
}
data = (unsigned char *)aad + l;
datalen = aadlen - l;
}
else {
data = (unsigned char *)aad;
datalen = aadlen;
}
if (datalen <= 0) return CRYPT_OK;
full_blocks = datalen/ocb->block_len;
full_blocks_len = full_blocks * ocb->block_len;
last_block_len = datalen - full_blocks_len;
for (x=0; x<full_blocks; x++) {
if ((err = ocb3_int_aad_add_block(ocb, data+x*ocb->block_len)) != CRYPT_OK) {
return err;
}
}
if (last_block_len>0) {
XMEMCPY(ocb->adata_buffer, data+full_blocks_len, last_block_len);
ocb->adata_buffer_bytes = last_block_len;
}
return CRYPT_OK;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */