/*
 ---------------------------------------------------------------------------
 Copyright (c) 2003, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
 All rights reserved.

 LICENSE TERMS

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 form is allowed (with or without changes) provided that:

   1. distributions of this source code include the above copyright
      notice, this list of conditions and the following disclaimer;

   2. distributions in binary form include the above copyright
      notice, this list of conditions and the following disclaimer
      in the documentation and/or other associated materials;

   3. the copyright holder's name is not used to endorse products
      built using this software without specific written permission.

 ALTERNATIVELY, provided that this notice is retained in full, this product
 may be distributed under the terms of the GNU General Public License (GPL),
 in which case the provisions of the GPL apply INSTEAD OF those given above.

 DISCLAIMER

 This software is provided 'as is' with no explicit or implied warranties
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 ---------------------------------------------------------------------------
 Issue Date: 1/08/2003

 My thanks go to Dag Arne Osvik for devising the schemes used here for key
 length derivation from the form of the key schedule

 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.

    aes_08t                 (an unsigned  8-bit type)
    aes_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 void *in_key, aes_encrypt_ctx cx[1]);
      aes_rval aes_encrypt_key192(const void *in_key, aes_encrypt_ctx cx[1]);
      aes_rval aes_encrypt_key256(const void *in_key, aes_encrypt_ctx cx[1]);
      aes_rval aes_encrypt(const void *in_blk,
                                 void *out_blk, const aes_encrypt_ctx cx[1]);

      aes_rval aes_decrypt_key128(const void *in_key, aes_decrypt_ctx cx[1]);
      aes_rval aes_decrypt_key192(const void *in_key, aes_decrypt_ctx cx[1]);
      aes_rval aes_decrypt_key256(const void *in_key, aes_decrypt_ctx cx[1]);
      aes_rval aes_decrypt(const void *in_blk,
                                 void *out_blk, 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 void *in_key) - 128 bit key
        Members:
            void key128(const void *in_key)
            void key192(const void *in_key)
            void key256(const void *in_key)
            void encrypt(const void *in_blk, void *out_blk) const

        Class AESdecrypt  for encryption
        Construtors:
            AESdecrypt(void)
            AESdecrypt(const void *in_key) - 128 bit key
        Members:
            void key128(const void *in_key)
            void key192(const void *in_key)
            void key256(const void *in_key)
            void decrypt(const void *in_blk, void *out_blk) 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 AES_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 AES_DLL

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

    CONFIGURATION OPTIONS (here and in aes.h)

    a. set AES_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.
*/

#ifndef _AESOPT_H
#define _AESOPT_H

#include "aes.h"

/*  START OF CONFIGURATION OPTIONS

    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.
*/

/*  DO NOT CHANGE THE FOLLOWING EIGHT DEFINES   */

#define NO_TABLES              0
#define ONE_TABLE              1
#define FOUR_TABLES            4
#define NONE                   0
#define PARTIAL                1
#define FULL                   2
#define AES_LITTLE_ENDIAN   1234 /* byte 0 is least significant (i386) */
#define AES_BIG_ENDIAN      4321 /* byte 0 is most significant (mc68k) */

/*  1. PLATFORM SPECIFIC INCLUDES */

#if defined( __FreeBSD__ ) || defined( __OpenBSD__ )
#  include <sys/endian.h>
#elif defined( BSD ) && ( BSD >= 199103 )
#  include <machine/endian.h>
#elif defined( __GNUC__ ) || defined( __GNU_LIBRARY__ )
#  include <endian.h>
#  include <byteswap.h>
#elif defined( linux )
#  include <endian.h>
#endif

#if defined(bswap32)
#define aes_sw32   bswap32
#elif defined(bswap_32)
#define aes_sw32   bswap_32
#endif

/*  2. BYTE ORDER IN 32-BIT WORDS

    To obtain the highest speed on processors with 32-bit words, this code
    needs to determine the order in which bytes are packed into such words.
    The following block of code is an attempt to capture the most obvious
    ways in which various environemnts define byte order. It may well fail,
    in which case the definitions will need to be set by editing at the
    points marked **** EDIT HERE IF NECESSARY **** below.  My thanks to
    Peter Gutmann for some of these defines.
*/

#if defined( __alpha__ ) || defined( __alpha ) || defined( i386 )       ||   \
    defined( __i386__ )  || defined( _M_I86 )  || defined( _M_IX86 )    ||   \
    defined( __OS2__ )   || defined( sun386 )  || defined( __TURBOC__ ) ||   \
    defined( vax )       || defined( vms )     || defined( VMS )        ||   \
    defined( __VMS ) 

#define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN

#endif

#if defined( AMIGA )    || defined( applec )  || defined( __AS400__ )  ||   \
    defined( _CRAY )    || defined( __hppa )  || defined( __hp9000 )   ||   \
    defined( ibm370 )   || defined( mc68000 ) || defined( m68k )       ||   \
    defined( __MRC__ )  || defined( __MVS__ ) || defined( __MWERKS__ ) ||   \
    defined( sparc )    || defined( __sparc)  || defined( SYMANTEC_C ) ||   \
    defined( __TANDEM ) || defined( THINK_C ) || defined( __VMCMS__ )
    
#define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN

#endif

/*  if the platform is not known, try to find its byte order from   */
/*  definitions in the headers  included earlier                    */

#if !defined(PLATFORM_BYTE_ORDER)

#if defined(LITTLE_ENDIAN) || defined(BIG_ENDIAN)
#  if defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
#    if defined(BYTE_ORDER)
#      if   (BYTE_ORDER == LITTLE_ENDIAN)
#        define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN
#      elif (BYTE_ORDER == BIG_ENDIAN)
#        define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN
#      endif
#    endif
#  elif defined(LITTLE_ENDIAN) && !defined(BIG_ENDIAN)
#    define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN
#  elif !defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
#    define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN
#  endif

#elif defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)
#  if defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN)
#    if defined(_BYTE_ORDER)
#      if   (_BYTE_ORDER == _LITTLE_ENDIAN)
#        define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN
#      elif (_BYTE_ORDER == _BIG_ENDIAN)
#        define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN
#      endif
#    endif
#  elif defined(_LITTLE_ENDIAN) && !defined(_BIG_ENDIAN)
#    define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN
#  elif !defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN)
#    define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN
#  endif

#elif defined(__LITTLE_ENDIAN__) || defined(__BIG_ENDIAN__)
#  if defined(__LITTLE_ENDIAN__) && defined(__BIG_ENDIAN__)
#    if defined(__BYTE_ORDER__)
#      if   (__BYTE_ORDER__ == __LITTLE_ENDIAN__)
#        define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN
#      elif (__BYTE_ORDER__ == __BIG_ENDIAN__)
#        define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN
#      endif
#    endif
#  elif defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
#    define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN
#  elif !defined(__LITTLE_ENDIAN__) && defined(__BIG_ENDIAN__)
#    define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN
#  endif

#elif 0     /* **** EDIT HERE IF NECESSARY **** */
#define PLATFORM_BYTE_ORDER AES_LITTLE_ENDIAN

#elif 0     /* **** EDIT HERE IF NECESSARY **** */
#define PLATFORM_BYTE_ORDER AES_BIG_ENDIAN

#else
#  error Please edit aesopt.h (line 263 or 266) to set the platform byte order
#endif

#endif

/*  3. 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.
*/
#ifdef AES_ENCRYPT
#define ENCRYPTION
#define ENCRYPTION_KEY_SCHEDULE
#endif

#ifdef AES_DECRYPT
#define DECRYPTION
#define DECRYPTION_KEY_SCHEDULE
#endif

/*  4. ASSEMBLER SUPPORT

    This define (which can be on the command line) enables the use of the
    assembler code routines for encryption and decryption with the C code
    only providing key scheduling
*/
#if 0
#define AES_ASM
#endif

/*  5. 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

    NOTE: Assembler code versions rely on PLATFORM_BYTE_ORDER being set
*/
#if 1 || defined(AES_ASM)
#define ALGORITHM_BYTE_ORDER PLATFORM_BYTE_ORDER
#elif 0
#define ALGORITHM_BYTE_ORDER AES_LITTLE_ENDIAN
#elif 0
#define ALGORITHM_BYTE_ORDER AES_BIG_ENDIAN
#else
#error The algorithm byte order is not defined
#endif

/*  6. 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