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/* 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 gcm_memory.c
GCM implementation, process a packet, by Tom St Denis
*/
#include "tomcrypt.h"
#ifdef LTC_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 initialization vector
@param IVlen The length of the initialization 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 LTC_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 LTC_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
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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