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/* gcm.h
*
* Galois counter mode, specified by NIST,
* http://csrc.nist.gov/publications/nistpubs/800-38D/SP-800-38D.pdf
*
*/
/* NOTE: Tentative interface, subject to change. No effort will be
made to avoid incompatible changes. */
/* nettle, low-level cryptographics library
*
* Copyright (C) 2011 Niels Möller
* Copyright (C) 2011 Katholieke Universiteit Leuven
*
* Contributed by Nikos Mavrogiannopoulos
*
* The nettle library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The nettle library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the nettle library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02111-1301, USA.
*/
#ifndef NETTLE_GCM_H_INCLUDED
#define NETTLE_GCM_H_INCLUDED
#include "aes.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Name mangling */
#define gcm_set_key nettle_gcm_set_key
#define gcm_set_iv nettle_gcm_set_iv
#define gcm_update nettle_gcm_update
#define gcm_encrypt nettle_gcm_encrypt
#define gcm_decrypt nettle_gcm_decrypt
#define gcm_digest nettle_gcm_digest
#define gcm_aes_set_key nettle_gcm_aes_set_key
#define gcm_aes_set_iv nettle_gcm_aes_set_iv
#define gcm_aes_update nettle_gcm_aes_update
#define gcm_aes_encrypt nettle_gcm_aes_encrypt
#define gcm_aes_decrypt nettle_gcm_aes_decrypt
#define gcm_aes_digest nettle_gcm_aes_digest
#define GCM_BLOCK_SIZE 16
#define GCM_IV_SIZE (GCM_BLOCK_SIZE - 4)
#define GCM_TABLE_BITS 8
/* To make sure that we have proper alignment. */
union gcm_block
{
uint8_t b[GCM_BLOCK_SIZE];
unsigned long w[GCM_BLOCK_SIZE / sizeof(unsigned long)];
};
/* Hashing subkey */
struct gcm_key
{
union gcm_block h[1 << GCM_TABLE_BITS];
};
/* Per-message state, depending on the iv */
struct gcm_ctx {
/* Original counter block */
union gcm_block iv;
/* Updated for each block. */
union gcm_block ctr;
/* Hashing state */
union gcm_block x;
uint64_t auth_size;
uint64_t data_size;
};
/* FIXME: Should use const for the cipher context. Then needs const for
nettle_crypt_func, which also rules out using that abstraction for
arcfour. */
void
gcm_set_key(struct gcm_key *key,
void *cipher, nettle_crypt_func *f);
void
gcm_set_iv(struct gcm_ctx *ctx, const struct gcm_key *key,
unsigned length, const uint8_t *iv);
void
gcm_update(struct gcm_ctx *ctx, const struct gcm_key *key,
unsigned length, const uint8_t *data);
void
gcm_encrypt(struct gcm_ctx *ctx, const struct gcm_key *key,
void *cipher, nettle_crypt_func *f,
unsigned length, uint8_t *dst, const uint8_t *src);
void
gcm_decrypt(struct gcm_ctx *ctx, const struct gcm_key *key,
void *cipher, nettle_crypt_func *f,
unsigned length, uint8_t *dst, const uint8_t *src);
void
gcm_digest(struct gcm_ctx *ctx, const struct gcm_key *key,
void *cipher, nettle_crypt_func *f,
unsigned length, uint8_t *digest);
/* Convenience macrology (not sure how useful it is) */
/* All-in-one context, with cipher, hash subkey, and message state. */
#define GCM_CTX(type) \
{ type cipher; struct gcm_key key; struct gcm_ctx gcm; }
/* NOTE: Avoid using NULL, as we don't include anything defining it. */
#define GCM_SET_KEY(ctx, set_key, encrypt, length, data) \
do { \
(set_key)(&(ctx)->cipher, (length), (data)); \
if (0) (encrypt)(&(ctx)->cipher, 0, (void *)0, (void *)0); \
gcm_set_key(&(ctx)->key, &(ctx)->cipher, \
(nettle_crypt_func *) (encrypt)); \
} while (0)
#define GCM_SET_IV(ctx, length, data) \
gcm_set_iv(&(ctx)->gcm, &(ctx)->key, (length), (data))
#define GCM_UPDATE(ctx, length, data) \
gcm_update(&(ctx)->gcm, &(ctx)->key, (length), (data))
#define GCM_ENCRYPT(ctx, encrypt, length, dst, src) \
(0 ? (encrypt)(&(ctx)->cipher, 0, (void *)0, (void *)0) \
: gcm_encrypt(&(ctx)->gcm, &(ctx)->key, &(ctx)->cipher, \
(nettle_crypt_func *) (encrypt), \
(length), (dst), (src)))
#define GCM_DECRYPT(ctx, encrypt, length, dst, src) \
(0 ? (encrypt)(&(ctx)->cipher, 0, (void *)0, (void *)0) \
: gcm_decrypt(&(ctx)->gcm, &(ctx)->key, &(ctx)->cipher, \
(nettle_crypt_func *) (encrypt), \
(length), (dst), (src)))
#define GCM_DIGEST(ctx, encrypt, length, digest) \
(0 ? (encrypt)(&(ctx)->cipher, 0, (void *)0, (void *)0) \
: gcm_digest(&(ctx)->gcm, &(ctx)->key, &(ctx)->cipher, \
(nettle_crypt_func *) (encrypt), \
(length), (digest)))
struct gcm_aes_ctx GCM_CTX(struct aes_ctx);
void
gcm_aes_set_key(struct gcm_aes_ctx *ctx,
unsigned length, const uint8_t *key);
void
gcm_aes_set_iv(struct gcm_aes_ctx *ctx,
unsigned length, const uint8_t *iv);
void
gcm_aes_update(struct gcm_aes_ctx *ctx,
unsigned length, const uint8_t *data);
void
gcm_aes_encrypt(struct gcm_aes_ctx *ctx,
unsigned length, uint8_t *dst, const uint8_t *src);
void
gcm_aes_decrypt(struct gcm_aes_ctx *ctx,
unsigned length, uint8_t *dst, const uint8_t *src);
void
gcm_aes_digest(struct gcm_aes_ctx *ctx, unsigned length, uint8_t *digest);
#ifdef __cplusplus
}
#endif
#endif /* NETTLE_GCM_H_INCLUDED */
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