aesopt.h

AES高级加密标准的C代码

/*
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 Copyright (c) 2003, Dr Brian Gladman, Worcester, UK.   All rights reserved.

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 Issue 01/08/2005

 This file contains the compilation options for AES (Rijndael) and code
 that is common across encryption, key scheduling and table generation.

 OPERATION

 These source code files implement the AES algorithm Rijndael designed by
 Joan Daemen and Vincent Rijmen. This version is designed for the standard
 block size of 16 bytes and for key sizes of 128, 192 and 256 bits (16, 24
 and 32 bytes).

 This version is designed for flexibility and speed using operations on
 32-bit words rather than operations on bytes.  It can be compiled with
 either big or little endian internal byte order but is faster when the
 native byte order for the processor is used.

 THE CIPHER INTERFACE

 The cipher interface is implemented as an array of bytes in which lower
 AES bit sequence indexes map to higher numeric significance within bytes.

  uint_8t                 (an unsigned  8-bit type)
  uint_32t                 (an unsigned 32-bit type)
  struct aes_encrypt_ctx  (structure for the cipher encryption context)
  struct aes_decrypt_ctx  (structure for the cipher decryption context)
  aes_rval                the function return type

  C subroutine calls:

  aes_rval aes_encrypt_key128(const unsigned char *key, aes_encrypt_ctx cx[1]);
  aes_rval aes_encrypt_key192(const unsigned char *key, aes_encrypt_ctx cx[1]);
  aes_rval aes_encrypt_key256(const unsigned char *key, aes_encrypt_ctx cx[1]);
  aes_rval aes_encrypt(const unsigned char *in, unsigned char *out,
                                                  const aes_encrypt_ctx cx[1]);

  aes_rval aes_decrypt_key128(const unsigned char *key, aes_decrypt_ctx cx[1]);
  aes_rval aes_decrypt_key192(const unsigned char *key, aes_decrypt_ctx cx[1]);
  aes_rval aes_decrypt_key256(const unsigned char *key, aes_decrypt_ctx cx[1]);
  aes_rval aes_decrypt(const unsigned char *in, unsigned char *out,
                                                  const aes_decrypt_ctx cx[1]);

 IMPORTANT NOTE: If you are using this C interface with dynamic tables make sure that
 you call genTabs() before AES is used so that the tables are initialised.

 C++ aes class subroutines:

     Class AESencrypt  for encryption

      Construtors:
          AESencrypt(void)
          AESencrypt(const unsigned char *key) - 128 bit key
      Members:
          aes_rval key128(const unsigned char *key)
          aes_rval key192(const unsigned char *key)
          aes_rval key256(const unsigned char *key)
          aes_rval encrypt(const unsigned char *in, unsigned char *out) const

      Class AESdecrypt  for encryption
      Construtors:
          AESdecrypt(void)
          AESdecrypt(const unsigned char *key) - 128 bit key
      Members:
          aes_rval key128(const unsigned char *key)
          aes_rval key192(const unsigned char *key)
          aes_rval key256(const unsigned char *key)
          aes_rval decrypt(const unsigned char *in, unsigned char *out) const

    COMPILATION

    The files used to provide AES (Rijndael) are

    a. aes.h for the definitions needed for use in C.
    b. aescpp.h for the definitions needed for use in C++.
    c. aesopt.h for setting compilation options (also includes common code).
    d. aescrypt.c for encryption and decrytpion, or
    e. aeskey.c for key scheduling.
    f. aestab.c for table loading or generation.
    g. aescrypt.asm for encryption and decryption using assembler code.
    h. aescrypt.mmx.asm for encryption and decryption using MMX assembler.

    To compile AES (Rijndael) for use in C code use aes.h and set the
    defines here for the facilities you need (key lengths, encryption
    and/or decryption). Do not define BUILD_DLL or AES_CPP.  Set the options
    for optimisations and table sizes here.

    To compile AES (Rijndael) for use in in C++ code use aescpp.h but do
    not define BUILD_DLL

    To compile AES (Rijndael) in C as a Dynamic Link Library DLL) use
    aes.h and include the BUILD_DLL define.

    CONFIGURATION OPTIONS (here and in aes.h)

    a. set BUILD_DLL in aes.h if AES (Rijndael) is to be compiled as a DLL
    b. You may need to set PLATFORM_BYTE_ORDER to define the byte order.
    c. If you want the code to run in a specific internal byte order, then
       ALGORITHM_BYTE_ORDER must be set accordingly.
    d. set other configuration options decribed below.
*/

#if !defined( _AESOPT_H )
#define _AESOPT_H

#if defined( __cplusplus ) && defined( AES_CPP )
#include "aescpp.h"
#else
#include "aes.h"
#endif

/*  PLATFORM SPECIFIC INCLUDES */

#include "edefs.h"

/*  CONFIGURATION - THE USE OF DEFINES

    Later in this section there are a number of defines that control the
    operation of the code.  In each section, the purpose of each define is
    explained so that the relevant form can be included or excluded by
    setting either 1's or 0's respectively on the branches of the related
    #if clauses.  The following local defines should not be changed.
*/

#define ENCRYPTION_IN_C     1
#define DECRYPTION_IN_C     2
#define ENC_KEYING_IN_C     4
#define DEC_KEYING_IN_C     8

#define ENCRYPTION_IN_ASM  16
#define DECRYPTION_IN_ASM  32
#define ENC_KEYING_IN_ASM  64
#define DEC_KEYING_IN_ASM 128

#define NO_TABLES           0
#define ONE_TABLE           1
#define FOUR_TABLES         4
#define NONE                0
#define PARTIAL             1
#define FULL                2

/*  1. BYTE ORDER WITHIN 32 BIT WORDS

    The fundamental data processing units in Rijndael are 8-bit bytes. The
    input, output and key input are all enumerated arrays of bytes in which
    bytes are numbered starting at zero and increasing to one less than the
    number of bytes in the array in question. This enumeration is only used
    for naming bytes and does not imply any adjacency or order relationship
    from one byte to another. When these inputs and outputs are considered
    as bit sequences, bits 8*n to 8*n+7 of the bit sequence are mapped to
    byte[n] with bit 8n+i in the sequence mapped to bit 7-i within the byte.
    In this implementation bits are numbered from 0 to 7 starting at the
    numerically least significant end of each byte (bit n represents 2^n).

    However, Rijndael can be implemented more efficiently using 32-bit
    words by packing bytes into words so that bytes 4*n to 4*n+3 are placed
    into word[n]. While in principle these bytes can be assembled into words
    in any positions, this implementation only supports the two formats in
    which bytes in adjacent positions within words also have adjacent byte
    numbers. This order is called big-endian if the lowest numbered bytes
    in words have the highest numeric significance and little-endian if the
    opposite applies.

    This code can work in either order irrespective of the order used by the
    machine on which it runs. Normally the internal byte order will be set
    to the order of the processor on which the code is to be run but this
    define can be used to reverse this in special situations

    WARNING: Assembler code versions rely on PLATFORM_BYTE_ORDER being set.
    This define will hence be redefined later (in section 4) if necessary
*/

#if 1 
#define ALGORITHM_BYTE_ORDER PLATFORM_BYTE_ORDER
#elif 0
#define ALGORITHM_BYTE_ORDER IS_LITTLE_ENDIAN
#elif 0
#define ALGORITHM_BYTE_ORDER IS_BIG_ENDIAN
#else
#error The algorithm byte order is not defined
#endif

/*  2. VIA ACE SUPPORT

    Define this option if support for the VIA ACE is required. This uses 
    inline assembler instructions and is only implemented for the Microsoft, 
    Intel and GCC compilers.  If VIA ACE is known to be present, then defining
    ASSUME_VIA_ACE_PRESENT will remove the ordinary encryption/decryption 
    code.  If USE_VIA_ACE_IF_PRESENT is defined then VIA ACE will be used if
    it is detected (both present and enabled) but the normal AES code will 
    also be present. 
    
    When VIA ACE is to be used, all AES encryption contexts MUST be 16 byte 
    aligned; other input/output buffers do not need to be 16 byte aligned 
    but there are very large performance gains if this can be arranged.  
    VIA ACE also requires the decryption key schedule to be in reverse 
    order (which the following defines ensure).
*/

#if 0 && !defined( USE_VIA_ACE_IF_PRESENT )
#define USE_VIA_ACE_IF_PRESENT
#endif

#if 0 && !defined( ASSUME_VIA_ACE_PRESENT )
#define ASSUME_VIA_ACE_PRESENT
#endif

#if !defined( _MSC_VER ) && !defined( __GNUC__ )
#  if defined( ASSUME_VIA_ACE_PRESENT )
#    undef ASSUME_VIA_ACE_PRESENT
#  endif
#  if defined( USE_VIA_ACE_IF_PRESENT )
#    undef USE_VIA_ACE_IF_PRESENT
#  endif
#endif

#if defined( ASSUME_VIA_ACE_PRESENT ) && !defined( USE_VIA_ACE_IF_PRESENT )
#define USE_VIA_ACE_IF_PRESENT
#endif

#if defined( USE_VIA_ACE_IF_PRESENT ) && !defined ( AES_REV_DKS )
#define AES_REV_DKS
#endif

/*  3. ASSEMBLER SUPPORT

    This define (which can be on the command line) enables the use of the
    assembler code routines for encryption, decryption and key scheduling
    as follows:

        ASM_V1		uses the assembler (aescrypt1.asm) for large tables with
                    tables and key scheduling in C
        ASM_V2		uses assembler (aescrypt2.asm) with compressed tables 
                    and key scheduling
        ASM_V2C		uses assembler (aescrypt2.asm) with compressed tables
                    but uses key scheduling in C
*/

#if 0 && !defined( ASM_V1 )
#define ASM_V1
#elif 0 && !defined( ASM_V2 )
#define ASM_V2
#elif 0 && !defined( ASM_V2C )
#define ASM_V2C
#endif

#if defined( ASM_V1 ) && (ALGORITHM_BYTE_ORDER != PLATFORM_BYTE_ORDER)
#undef  ALGORITHM_BYTE_ORDER
#define ALGORITHM_BYTE_ORDER PLATFORM_BYTE_ORDER
#endif

/*  4. FUNCTIONS REQUIRED

    This implementation provides subroutines for encryption, decryption
    and for setting the three key lengths (separately) for encryption
    and decryption. When the assembler code is not being used the following
    definition blocks allow the selection of the routines that are to be
    included in the compilation.
*/

#if !defined( AES_ENCRYPT )
#  define EFUNCS_IN_C   0
#elif defined( USE_VIA_ACE_IF_PRESENT ) || defined( ASM_V1 )
#  define EFUNCS_IN_C   ENC_KEYING_IN_C
#elif defined( ASM_V2C )
#  define EFUNCS_IN_C   ENC_KEYING_IN_C
#elif !defined( ASM_V2 )
#  define EFUNCS_IN_C   ( ENCRYPTION_IN_C | ENC_KEYING_IN_C )
#else
#  define EFUNCS_IN_C   0
#endif

#if !defined( AES_DECRYPT )
#  define DFUNCS_IN_C   0
#elif defined( USE_VIA_ACE_IF_PRESENT ) || defined( ASM_V1 )
#  define DFUNCS_IN_C   DEC_KEYING_IN_C
#elif defined( ASM_V2C )
#  define DFUNCS_IN_C   DEC_KEYING_IN_C
#elif !defined( ASM_V2 )
#  define DFUNCS_IN_C   ( DECRYPTION_IN_C | DEC_KEYING_IN_C )
#else
#  define DFUNCS_IN_C   0
#endif

#define FUNCS_IN_C  ( EFUNCS_IN_C | DFUNCS_IN_C )

/*  5. FAST INPUT/OUTPUT OPERATIONS.

    On some machines it is possible to improve speed by transferring the
    bytes in the input and output arrays to and from the internal 32-bit
    variables by addressing these arrays as if they are arrays of 32-bit
    words.  On some machines this will always be possible but there may
    be a large performance penalty if the byte arrays are not aligned on
    the normal word boundaries. On other machines this technique will
    lead to memory access errors when such 32-bit word accesses are not
    properly aligned. The option SAFE_IO avoids such problems but will
    often be slower on those machines that support misaligned access
    (especially so if care is taken to align the input  and output byte
    arrays on 32-bit word boundaries). If SAFE_IO is not defined it is
    assumed that access to byte arrays as if they are arrays of 32-bit
    words will not cause problems when such accesses are misaligned.
*/
#if 1 && !defined(_MSC_VER)
#define SAFE_IO
#endif

/*  6. LOOP UNROLLING

    The code for encryption and decrytpion cycles through a number of rounds
    that can be implemented either in a loop or by expanding the code into a
    long sequence of instructions, the latter producing a larger program but
    one that will often be much faster. The latter is called loop unrolling.
    There are also potential speed advantages in expanding two iterations in
    a loop with half the number of iterations, which is called partial loop
    unrolling.  The following options allow partial or full loop unrolling
    to be set independently for encryption and decryption
*/
#if 1
#define ENC_UNROLL  FULL
#elif 0
#define ENC_UNROLL  PARTIAL
#else
#define ENC_UNROLL  NONE
#endif

#if 1
#define DEC_UNROLL  FULL
#elif 0
#define DEC_UNROLL  PARTIAL
#else
#define DEC_UNROLL  NONE
#endif

/*  7. FAST FINITE FIELD OPERATIONS

    If this section is included, tables are used to provide faster finite
    field arithmetic (this has no effect if FIXED_TABLES is defined).
*/
#if 1
#define FF_TABLES