/* 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.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
*/
/**
@file gcm_memory.c
GCM implementation, process a packet, by Tom St Denis
*/
#include "tomcrypt.h"
#ifdef GCM_MODE
/**
Process an entire GCM packet in one call.
@param cipher Index of cipher to use
@param key The secret key
@param keylen The length of the secret key
@param IV The initial vector
@param IVlen The length of the initial vector
@param adata The additional authentication data (header)
@param adatalen The length of the adata
@param pt The plaintext
@param ptlen The length of the plaintext (ciphertext length is the same)
@param ct The ciphertext
@param tag [out] The MAC tag
@param taglen [in/out] The MAC tag length
@param direction Encrypt or Decrypt mode (GCM_ENCRYPT or GCM_DECRYPT)
@return CRYPT_OK on success
*/
int
gcm_memory(
int
cipher,
const
unsigned
char
*key, unsigned
long
keylen,
const
unsigned
char
*IV, unsigned
long
IVlen,
const
unsigned
char
*adata, unsigned
long
adatalen,
unsigned
char
*pt, unsigned
long
ptlen,
unsigned
char
*ct,
unsigned
char
*tag, unsigned
long
*taglen,
int
direction)
{
void
*orig;
gcm_state *gcm;
int
err;
if
((err = cipher_is_valid(cipher)) != CRYPT_OK) {
return
err;
}
if
(cipher_descriptor[cipher].accel_gcm_memory != NULL) {
return
cipher_descriptor[cipher].accel_gcm_memory
(key, keylen,
IV, IVlen,
adata, adatalen,
pt, ptlen,
ct,
tag, taglen,
direction);
}
#ifndef GCM_TABLES_SSE2
orig = gcm = XMALLOC(
sizeof
(*gcm));
#else
orig = gcm = XMALLOC(
sizeof
(*gcm) + 16);
#endif
if
(gcm == NULL) {
return
CRYPT_MEM;
}
/* Force GCM to be on a multiple of 16 so we can use 128-bit aligned operations
* note that we only modify gcm and keep orig intact. This code is not portable
* but again it's only for SSE2 anyways, so who cares?
*/
#ifdef GCM_TABLES_SSE2
if
((unsigned
long
)gcm & 15) {
gcm = (gcm_state *)((unsigned
long
)gcm + (16 - ((unsigned
long
)gcm & 15)));
}
#endif
if
((err = gcm_init(gcm, cipher, key, keylen)) != CRYPT_OK) {
goto
LTC_ERR;
}
if
((err = gcm_add_iv(gcm, IV, IVlen)) != CRYPT_OK) {
goto
LTC_ERR;
}
if
((err = gcm_add_aad(gcm, adata, adatalen)) != CRYPT_OK) {
goto
LTC_ERR;
}
if
((err = gcm_process(gcm, pt, ptlen, ct, direction)) != CRYPT_OK) {
goto
LTC_ERR;
}
err = gcm_done(gcm, tag, taglen);
LTC_ERR:
XFREE(orig);
return
err;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/encauth/gcm/gcm_memory.c,v $ */
/* $Revision: 1.23 $ */
/* $Date: 2006/09/07 10:00:57 $ */