mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-11-25 00:48:19 +00:00
234 lines
10 KiB
C
234 lines
10 KiB
C
/*
|
|
---------------------------------------------------------------------------
|
|
Copyright (c) 1998-2010, Brian Gladman, Worcester, UK. All rights reserved.
|
|
|
|
The redistribution and use of this software (with or without changes)
|
|
is allowed without the payment of fees or royalties provided that:
|
|
|
|
source code distributions include the above copyright notice, this
|
|
list of conditions and the following disclaimer;
|
|
|
|
binary distributions include the above copyright notice, this list
|
|
of conditions and the following disclaimer in their documentation.
|
|
|
|
This software is provided 'as is' with no explicit or implied warranties
|
|
in respect of its operation, including, but not limited to, correctness
|
|
and fitness for purpose.
|
|
---------------------------------------------------------------------------
|
|
Issue Date: 11/01/2011
|
|
|
|
I am grateful for the work done by Mark Rodenkirch and Jason Papadopoulos
|
|
in helping to remove a bug in the operation of this code on big endian
|
|
systems when fast buffer operations are enabled.
|
|
---------------------------------------------------------------------------
|
|
*/
|
|
|
|
#ifndef _GCM_H
|
|
#define _GCM_H
|
|
|
|
#include "aes.h"
|
|
#include "gf128mul.h"
|
|
|
|
/* USER DEFINABLE OPTIONS (Further options need to be set in gf128mul.h) */
|
|
|
|
/* UNIT_BITS sets the size of variables used to process 16 byte buffers
|
|
when the buffer alignment allows this. When buffers are processed
|
|
in bytes, 16 individual operations are invoolved. But if, say, such
|
|
a buffer is divided into 4 32 bit variables, it can then be processed
|
|
in 4 operations, making the code typically much faster. In general
|
|
it will pay to use the longest natively supported size, which will
|
|
probably be 32 or 64 bits in 32 and 64 bit systems respectively.
|
|
*/
|
|
|
|
#if defined( UNIT_BITS )
|
|
# undef UNIT_BITS
|
|
#endif
|
|
|
|
#if !defined( UNIT_BITS )
|
|
# if PLATFORM_BYTE_ORDER == IS_BIG_ENDIAN
|
|
# if 0
|
|
# define UNIT_BITS 8
|
|
# elif 0
|
|
# define UNIT_BITS 32
|
|
# elif 1
|
|
# define UNIT_BITS 64
|
|
# endif
|
|
# elif defined( _WIN64 )
|
|
# define UNIT_BITS 64
|
|
# else
|
|
# define UNIT_BITS 32
|
|
# endif
|
|
#endif
|
|
|
|
#if UNIT_BITS == 64 && !defined( NEED_UINT_64T )
|
|
# define NEED_UINT_64T
|
|
#endif
|
|
|
|
/* END OF USER DEFINABLE OPTIONS */
|
|
|
|
/* After encryption or decryption operations the return value of
|
|
'compute tag' will be one of the values RETURN_GOOD, RETURN_WARN
|
|
or RETURN_ERROR, the latter indicating an error. A return value
|
|
RETURN_GOOD indicates that both encryption and authentication
|
|
have taken place and resulted in the returned tag value. If
|
|
the returned value is RETURN_WARN, the tag value is the result
|
|
of authentication alone without encryption (CCM) or decryption
|
|
(GCM and EAX).
|
|
*/
|
|
#ifndef RETURN_GOOD
|
|
# define RETURN_WARN 1
|
|
# define RETURN_GOOD 0
|
|
# define RETURN_ERROR -1
|
|
#endif
|
|
|
|
#if defined(__cplusplus)
|
|
extern "C"
|
|
{
|
|
#endif
|
|
|
|
#ifndef RET_TYPE_DEFINED
|
|
typedef int ret_type;
|
|
#endif
|
|
UNIT_TYPEDEF(gcm_unit_t, UNIT_BITS);
|
|
BUFR_TYPEDEF(gcm_buf_t, UNIT_BITS, AES_BLOCK_SIZE);
|
|
|
|
#define GCM_BLOCK_SIZE AES_BLOCK_SIZE
|
|
|
|
/* The GCM-AES context */
|
|
|
|
typedef struct
|
|
{
|
|
#if defined( TABLES_64K )
|
|
gf_t64k_a gf_t64k;
|
|
#endif
|
|
#if defined( TABLES_8K )
|
|
gf_t8k_a gf_t8k;
|
|
#endif
|
|
#if defined( TABLES_4K )
|
|
gf_t4k_a gf_t4k;
|
|
#endif
|
|
#if defined( TABLES_256 )
|
|
gf_t256_a gf_t256;
|
|
#endif
|
|
gcm_buf_t ctr_val; /* CTR counter value */
|
|
gcm_buf_t enc_ctr; /* encrypted CTR block */
|
|
gcm_buf_t hdr_ghv; /* ghash buffer (header) */
|
|
gcm_buf_t txt_ghv; /* ghash buffer (ciphertext) */
|
|
gf_t ghash_h; /* ghash H value */
|
|
aes_encrypt_ctx aes[1]; /* AES encryption context */
|
|
uint32_t y0_val; /* initial counter value */
|
|
uint32_t hdr_cnt; /* header bytes so far */
|
|
uint32_t txt_ccnt; /* text bytes so far (encrypt) */
|
|
uint32_t txt_acnt; /* text bytes so far (auth) */
|
|
} gcm_ctx;
|
|
|
|
/* The following calls handle mode initialisation, keying and completion */
|
|
|
|
ret_type gcm_init_and_key( /* initialise mode and set key */
|
|
const unsigned char key[], /* the key value */
|
|
unsigned long key_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
ret_type gcm_end( /* clean up and end operation */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
/* The following calls handle complete messages in memory as one operation */
|
|
|
|
ret_type gcm_encrypt_message( /* encrypt an entire message */
|
|
const unsigned char iv[], /* the initialisation vector */
|
|
unsigned long iv_len, /* and its length in bytes */
|
|
const unsigned char hdr[], /* the header buffer */
|
|
unsigned long hdr_len, /* and its length in bytes */
|
|
unsigned char msg[], /* the message buffer */
|
|
unsigned long msg_len, /* and its length in bytes */
|
|
unsigned char tag[], /* the buffer for the tag */
|
|
unsigned long tag_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
/* RETURN_GOOD is returned if the input tag */
|
|
/* matches that for the decrypted message */
|
|
ret_type gcm_decrypt_message( /* decrypt an entire message */
|
|
const unsigned char iv[], /* the initialisation vector */
|
|
unsigned long iv_len, /* and its length in bytes */
|
|
const unsigned char hdr[], /* the header buffer */
|
|
unsigned long hdr_len, /* and its length in bytes */
|
|
unsigned char msg[], /* the message buffer */
|
|
unsigned long msg_len, /* and its length in bytes */
|
|
const unsigned char tag[], /* the buffer for the tag */
|
|
unsigned long tag_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
/* The following calls handle messages in a sequence of operations followed */
|
|
/* by tag computation after the sequence has been completed. In these calls */
|
|
/* the user is responsible for verfiying the computed tag on decryption */
|
|
|
|
ret_type gcm_init_message( /* initialise a new message */
|
|
const unsigned char iv[], /* the initialisation vector */
|
|
unsigned long iv_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
ret_type gcm_auth_header( /* authenticate the header */
|
|
const unsigned char hdr[], /* the header buffer */
|
|
unsigned long hdr_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
ret_type gcm_encrypt( /* encrypt & authenticate data */
|
|
unsigned char data[], /* the data buffer */
|
|
unsigned long data_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
ret_type gcm_decrypt( /* authenticate & decrypt data */
|
|
unsigned char data[], /* the data buffer */
|
|
unsigned long data_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
ret_type gcm_compute_tag( /* compute authentication tag */
|
|
unsigned char tag[], /* the buffer for the tag */
|
|
unsigned long tag_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
/* The use of the following calls should be avoided if possible because
|
|
their use requires a very good understanding of the way this encryption
|
|
mode works and the way in which this code implements it in order to use
|
|
them correctly.
|
|
|
|
The gcm_auth_data routine is used to authenticate encrypted message data.
|
|
In message encryption gcm_crypt_data must be called before gcm_auth_data
|
|
is called since it is encrypted data that is authenticated. In message
|
|
decryption authentication must occur before decryption and data can be
|
|
authenticated without being decrypted if necessary.
|
|
|
|
If these calls are used it is up to the user to ensure that these routines
|
|
are called in the correct order and that the correct data is passed to
|
|
them.
|
|
|
|
When gcm_compute_tag is called it is assumed that an error in use has
|
|
occurred if both encryption (or decryption) and authentication have taken
|
|
place but the total lengths of the message data respectively authenticated
|
|
and encrypted are not the same. If authentication has taken place but
|
|
there has been no corresponding encryption or decryption operations (none
|
|
at all) only a warning is issued. This should be treated as an error if it
|
|
occurs during encryption but it is only signalled as a warning as it might
|
|
be intentional when decryption operations are involved (this avoids having
|
|
different compute tag functions for encryption and decryption). Decryption
|
|
operations can be undertaken freely after authetication but if the tag is
|
|
computed after such operations an error will be signalled if the lengths
|
|
of the data authenticated and decrypted don't match.
|
|
*/
|
|
|
|
ret_type gcm_auth_data( /* authenticate ciphertext data */
|
|
const unsigned char data[], /* the data buffer */
|
|
unsigned long data_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
ret_type gcm_crypt_data( /* encrypt or decrypt data */
|
|
unsigned char data[], /* the data buffer */
|
|
unsigned long data_len, /* and its length in bytes */
|
|
gcm_ctx ctx[1]); /* the mode context */
|
|
|
|
#if defined(__cplusplus)
|
|
}
|
|
#endif
|
|
|
|
#endif
|