/*
 ---------------------------------------------------------------------------
 Copyright (c) 1998-2008, Brian Gladman, Worcester, UK. All rights reserved.

 LICENSE TERMS

 The redistribution and use of this software (with or without changes)
 is allowed without the payment of fees or royalties provided that:

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

  2. binary distributions include the above copyright notice, this list
     of conditions and the following disclaimer in their documentation;

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

 DISCLAIMER

 This software is provided 'as is' with no explicit or implied warranties
 in respect of its properties, including, but not limited to, correctness
 and/or fitness for purpose.
 ---------------------------------------------------------------------------
 Issue 09/09/2006

 This is an AES implementation that uses only 8-bit byte operations on the
 cipher state (there are options to use 32-bit types if available).

 The combination of mix columns and byte substitution used here is based on
 that developed by Karl Malbrain. His contribution is acknowledged.
 */

/* define if you have a fast memcpy function on your system */
#if 0
#  define HAVE_MEMCPY
#  include <string.h>
#  if defined( _MSC_VER )
#    include <intrin.h>
#    pragma intrinsic( memcpy )
#  endif
#endif


#include <stdlib.h>
#include <stdint.h>

/* define if you have fast 32-bit types on your system */
#if ( __CORTEX_M != 0 ) // if Cortex is different from M0/M0+
#  define HAVE_UINT_32T
#endif

/* define if you don't want any tables */
#if 1
#  define USE_TABLES
#endif

/*  On Intel Core 2 duo VERSION_1 is faster */

/* alternative versions (test for performance on your system) */
#if 1
#  define VERSION_1
#endif

#include "lorawan_aes.h"

//#if defined( HAVE_UINT_32T )
//  typedef unsigned long uint32_t;
//#endif

/* functions for finite field multiplication in the AES Galois field    */

#define WPOLY   0x011b
#define BPOLY     0x1b
#define DPOLY   0x008d

#define f1(x)   (x)
#define f2(x)   ((x << 1) ^ (((x >> 7) & 1) * WPOLY))
#define f4(x)   ((x << 2) ^ (((x >> 6) & 1) * WPOLY) ^ (((x >> 6) & 2) * WPOLY))
#define f8(x)   ((x << 3) ^ (((x >> 5) & 1) * WPOLY) ^ (((x >> 5) & 2) * WPOLY) \
                          ^ (((x >> 5) & 4) * WPOLY))
#define d2(x)   (((x) >> 1) ^ ((x) & 1 ? DPOLY : 0))

#define f3(x)   (f2(x) ^ x)
#define f9(x)   (f8(x) ^ x)
#define fb(x)   (f8(x) ^ f2(x) ^ x)
#define fd(x)   (f8(x) ^ f4(x) ^ x)
#define fe(x)   (f8(x) ^ f4(x) ^ f2(x))

#if defined( USE_TABLES )

#define sb_data(w) {    /* S Box data values */                            \
    w(0x63), w(0x7c), w(0x77), w(0x7b), w(0xf2), w(0x6b), w(0x6f), w(0xc5),\
    w(0x30), w(0x01), w(0x67), w(0x2b), w(0xfe), w(0xd7), w(0xab), w(0x76),\
    w(0xca), w(0x82), w(0xc9), w(0x7d), w(0xfa), w(0x59), w(0x47), w(0xf0),\
    w(0xad), w(0xd4), w(0xa2), w(0xaf), w(0x9c), w(0xa4), w(0x72), w(0xc0),\
    w(0xb7), w(0xfd), w(0x93), w(0x26), w(0x36), w(0x3f), w(0xf7), w(0xcc),\
    w(0x34), w(0xa5), w(0xe5), w(0xf1), w(0x71), w(0xd8), w(0x31), w(0x15),\
    w(0x04), w(0xc7), w(0x23), w(0xc3), w(0x18), w(0x96), w(0x05), w(0x9a),\
    w(0x07), w(0x12), w(0x80), w(0xe2), w(0xeb), w(0x27), w(0xb2), w(0x75),\
    w(0x09), w(0x83), w(0x2c), w(0x1a), w(0x1b), w(0x6e), w(0x5a), w(0xa0),\
    w(0x52), w(0x3b), w(0xd6), w(0xb3), w(0x29), w(0xe3), w(0x2f), w(0x84),\
    w(0x53), w(0xd1), w(0x00), w(0xed), w(0x20), w(0xfc), w(0xb1), w(0x5b),\
    w(0x6a), w(0xcb), w(0xbe), w(0x39), w(0x4a), w(0x4c), w(0x58), w(0xcf),\
    w(0xd0), w(0xef), w(0xaa), w(0xfb), w(0x43), w(0x4d), w(0x33), w(0x85),\
    w(0x45), w(0xf9), w(0x02), w(0x7f), w(0x50), w(0x3c), w(0x9f), w(0xa8),\
    w(0x51), w(0xa3), w(0x40), w(0x8f), w(0x92), w(0x9d), w(0x38), w(0xf5),\
    w(0xbc), w(0xb6), w(0xda), w(0x21), w(0x10), w(0xff), w(0xf3), w(0xd2),\
    w(0xcd), w(0x0c), w(0x13), w(0xec), w(0x5f), w(0x97), w(0x44), w(0x17),\
    w(0xc4), w(0xa7), w(0x7e), w(0x3d), w(0x64), w(0x5d), w(0x19), w(0x73),\
    w(0x60), w(0x81), w(0x4f), w(0xdc), w(0x22), w(0x2a), w(0x90), w(0x88),\
    w(0x46), w(0xee), w(0xb8), w(0x14), w(0xde), w(0x5e), w(0x0b), w(0xdb),\
    w(0xe0), w(0x32), w(0x3a), w(0x0a), w(0x49), w(0x06), w(0x24), w(0x5c),\
    w(0xc2), w(0xd3), w(0xac), w(0x62), w(0x91), w(0x95), w(0xe4), w(0x79),\
    w(0xe7), w(0xc8), w(0x37), w(0x6d), w(0x8d), w(0xd5), w(0x4e), w(0xa9),\
    w(0x6c), w(0x56), w(0xf4), w(0xea), w(0x65), w(0x7a), w(0xae), w(0x08),\
    w(0xba), w(0x78), w(0x25), w(0x2e), w(0x1c), w(0xa6), w(0xb4), w(0xc6),\
    w(0xe8), w(0xdd), w(0x74), w(0x1f), w(0x4b), w(0xbd), w(0x8b), w(0x8a),\
    w(0x70), w(0x3e), w(0xb5), w(0x66), w(0x48), w(0x03), w(0xf6), w(0x0e),\
    w(0x61), w(0x35), w(0x57), w(0xb9), w(0x86), w(0xc1), w(0x1d), w(0x9e),\
    w(0xe1), w(0xf8), w(0x98), w(0x11), w(0x69), w(0xd9), w(0x8e), w(0x94),\
    w(0x9b), w(0x1e), w(0x87), w(0xe9), w(0xce), w(0x55), w(0x28), w(0xdf),\
    w(0x8c), w(0xa1), w(0x89), w(0x0d), w(0xbf), w(0xe6), w(0x42), w(0x68),\
    w(0x41), w(0x99), w(0x2d), w(0x0f), w(0xb0), w(0x54), w(0xbb), w(0x16) }

#define isb_data(w) {   /* inverse S Box data values */                    \
    w(0x52), w(0x09), w(0x6a), w(0xd5), w(0x30), w(0x36), w(0xa5), w(0x38),\
    w(0xbf), w(0x40), w(0xa3), w(0x9e), w(0x81), w(0xf3), w(0xd7), w(0xfb),\
    w(0x7c), w(0xe3), w(0x39), w(0x82), w(0x9b), w(0x2f), w(0xff), w(0x87),\
    w(0x34), w(0x8e), w(0x43), w(0x44), w(0xc4), w(0xde), w(0xe9), w(0xcb),\
    w(0x54), w(0x7b), w(0x94), w(0x32), w(0xa6), w(0xc2), w(0x23), w(0x3d),\
    w(0xee), w(0x4c), w(0x95), w(0x0b), w(0x42), w(0xfa), w(0xc3), w(0x4e),\
    w(0x08), w(0x2e), w(0xa1), w(0x66), w(0x28), w(0xd9), w(0x24), w(0xb2),\
    w(0x76), w(0x5b), w(0xa2), w(0x49), w(0x6d), w(0x8b), w(0xd1), w(0x25),\
    w(0x72), w(0xf8), w(0xf6), w(0x64), w(0x86), w(0x68), w(0x98), w(0x16),\
    w(0xd4), w(0xa4), w(0x5c), w(0xcc), w(0x5d), w(0x65), w(0xb6), w(0x92),\
    w(0x6c), w(0x70), w(0x48), w(0x50), w(0xfd), w(0xed), w(0xb9), w(0xda),\
    w(0x5e), w(0x15), w(0x46), w(0x57), w(0xa7), w(0x8d), w(0x9d), w(0x84),\
    w(0x90), w(0xd8), w(0xab), w(0x00), w(0x8c), w(0xbc), w(0xd3), w(0x0a),\
    w(0xf7), w(0xe4), w(0x58), w(0x05), w(0xb8), w(0xb3), w(0x45), w(0x06),\
    w(0xd0), w(0x2c), w(0x1e), w(0x8f), w(0xca), w(0x3f), w(0x0f), w(0x02),\
    w(0xc1), w(0xaf), w(0xbd), w(0x03), w(0x01), w(0x13), w(0x8a), w(0x6b),\
    w(0x3a), w(0x91), w(0x11), w(0x41), w(0x4f), w(0x67), w(0xdc), w(0xea),\
    w(0x97), w(0xf2), w(0xcf), w(0xce), w(0xf0), w(0xb4), w(0xe6), w(0x73),\
    w(0x96), w(0xac), w(0x74), w(0x22), w(0xe7), w(0xad), w(0x35), w(0x85),\
    w(0xe2), w(0xf9), w(0x37), w(0xe8), w(0x1c), w(0x75), w(0xdf), w(0x6e),\
    w(0x47), w(0xf1), w(0x1a), w(0x71), w(0x1d), w(0x29), w(0xc5), w(0x89),\
    w(0x6f), w(0xb7), w(0x62), w(0x0e), w(0xaa), w(0x18), w(0xbe), w(0x1b),\
    w(0xfc), w(0x56), w(0x3e), w(0x4b), w(0xc6), w(0xd2), w(0x79), w(0x20),\
    w(0x9a), w(0xdb), w(0xc0), w(0xfe), w(0x78), w(0xcd), w(0x5a), w(0xf4),\
    w(0x1f), w(0xdd), w(0xa8), w(0x33), w(0x88), w(0x07), w(0xc7), w(0x31),\
    w(0xb1), w(0x12), w(0x10), w(0x59), w(0x27), w(0x80), w(0xec), w(0x5f),\
    w(0x60), w(0x51), w(0x7f), w(0xa9), w(0x19), w(0xb5), w(0x4a), w(0x0d),\
    w(0x2d), w(0xe5), w(0x7a), w(0x9f), w(0x93), w(0xc9), w(0x9c), w(0xef),\
    w(0xa0), w(0xe0), w(0x3b), w(0x4d), w(0xae), w(0x2a), w(0xf5), w(0xb0),\
    w(0xc8), w(0xeb), w(0xbb), w(0x3c), w(0x83), w(0x53), w(0x99), w(0x61),\
    w(0x17), w(0x2b), w(0x04), w(0x7e), w(0xba), w(0x77), w(0xd6), w(0x26),\
    w(0xe1), w(0x69), w(0x14), w(0x63), w(0x55), w(0x21), w(0x0c), w(0x7d) }

#define mm_data(w) {    /* basic data for forming finite field tables */   \
    w(0x00), w(0x01), w(0x02), w(0x03), w(0x04), w(0x05), w(0x06), w(0x07),\
    w(0x08), w(0x09), w(0x0a), w(0x0b), w(0x0c), w(0x0d), w(0x0e), w(0x0f),\
    w(0x10), w(0x11), w(0x12), w(0x13), w(0x14), w(0x15), w(0x16), w(0x17),\
    w(0x18), w(0x19), w(0x1a), w(0x1b), w(0x1c), w(0x1d), w(0x1e), w(0x1f),\
    w(0x20), w(0x21), w(0x22), w(0x23), w(0x24), w(0x25), w(0x26), w(0x27),\
    w(0x28), w(0x29), w(0x2a), w(0x2b), w(0x2c), w(0x2d), w(0x2e), w(0x2f),\
    w(0x30), w(0x31), w(0x32), w(0x33), w(0x34), w(0x35), w(0x36), w(0x37),\
    w(0x38), w(0x39), w(0x3a), w(0x3b), w(0x3c), w(0x3d), w(0x3e), w(0x3f),\
    w(0x40), w(0x41), w(0x42), w(0x43), w(0x44), w(0x45), w(0x46), w(0x47),\
    w(0x48), w(0x49), w(0x4a), w(0x4b), w(0x4c), w(0x4d), w(0x4e), w(0x4f),\
    w(0x50), w(0x51), w(0x52), w(0x53), w(0x54), w(0x55), w(0x56), w(0x57),\
    w(0x58), w(0x59), w(0x5a), w(0x5b), w(0x5c), w(0x5d), w(0x5e), w(0x5f),\
    w(0x60), w(0x61), w(0x62), w(0x63), w(0x64), w(0x65), w(0x66), w(0x67),\
    w(0x68), w(0x69), w(0x6a), w(0x6b), w(0x6c), w(0x6d), w(0x6e), w(0x6f),\
    w(0x70), w(0x71), w(0x72), w(0x73), w(0x74), w(0x75), w(0x76), w(0x77),\
    w(0x78), w(0x79), w(0x7a), w(0x7b), w(0x7c), w(0x7d), w(0x7e), w(0x7f),\
    w(0x80), w(0x81), w(0x82), w(0x83), w(0x84), w(0x85), w(0x86), w(0x87),\
    w(0x88), w(0x89), w(0x8a), w(0x8b), w(0x8c), w(0x8d), w(0x8e), w(0x8f),\
    w(0x90), w(0x91), w(0x92), w(0x93), w(0x94), w(0x95), w(0x96), w(0x97),\
    w(0x98), w(0x99), w(0x9a), w(0x9b), w(0x9c), w(0x9d), w(0x9e), w(0x9f),\
    w(0xa0), w(0xa1), w(0xa2), w(0xa3), w(0xa4), w(0xa5), w(0xa6), w(0xa7),\
    w(0xa8), w(0xa9), w(0xaa), w(0xab), w(0xac), w(0xad), w(0xae), w(0xaf),\
    w(0xb0), w(0xb1), w(0xb2), w(0xb3), w(0xb4), w(0xb5), w(0xb6), w(0xb7),\
    w(0xb8), w(0xb9), w(0xba), w(0xbb), w(0xbc), w(0xbd), w(0xbe), w(0xbf),\
    w(0xc0), w(0xc1), w(0xc2), w(0xc3), w(0xc4), w(0xc5), w(0xc6), w(0xc7),\
    w(0xc8), w(0xc9), w(0xca), w(0xcb), w(0xcc), w(0xcd), w(0xce), w(0xcf),\
    w(0xd0), w(0xd1), w(0xd2), w(0xd3), w(0xd4), w(0xd5), w(0xd6), w(0xd7),\
    w(0xd8), w(0xd9), w(0xda), w(0xdb), w(0xdc), w(0xdd), w(0xde), w(0xdf),\
    w(0xe0), w(0xe1), w(0xe2), w(0xe3), w(0xe4), w(0xe5), w(0xe6), w(0xe7),\
    w(0xe8), w(0xe9), w(0xea), w(0xeb), w(0xec), w(0xed), w(0xee), w(0xef),\
    w(0xf0), w(0xf1), w(0xf2), w(0xf3), w(0xf4), w(0xf5), w(0xf6), w(0xf7),\
    w(0xf8), w(0xf9), w(0xfa), w(0xfb), w(0xfc), w(0xfd), w(0xfe), w(0xff) }

static const uint8_t sbox[256]  =  sb_data(f1);

#if defined( AES_DEC_PREKEYED )
static const uint8_t isbox[256] = isb_data(f1);
#endif

static const uint8_t gfm2_sbox[256] = sb_data(f2);
static const uint8_t gfm3_sbox[256] = sb_data(f3);

#if defined( AES_DEC_PREKEYED )
static const uint8_t gfmul_9[256] = mm_data(f9);
static const uint8_t gfmul_b[256] = mm_data(fb);
static const uint8_t gfmul_d[256] = mm_data(fd);
static const uint8_t gfmul_e[256] = mm_data(fe);
#endif

#define s_box(x)     sbox[(x)]
#if defined( AES_DEC_PREKEYED )
#define is_box(x)    isbox[(x)]
#endif
#define gfm2_sb(x)   gfm2_sbox[(x)]
#define gfm3_sb(x)   gfm3_sbox[(x)]
#if defined( AES_DEC_PREKEYED )
#define gfm_9(x)     gfmul_9[(x)]
#define gfm_b(x)     gfmul_b[(x)]
#define gfm_d(x)     gfmul_d[(x)]
#define gfm_e(x)     gfmul_e[(x)]
#endif
#else

/* this is the high bit of x right shifted by 1 */
/* position. Since the starting polynomial has  */
/* 9 bits (0x11b), this right shift keeps the   */
/* values of all top bits within a byte         */

static uint8_t hibit(const uint8_t x)
{   uint8_t r = (uint8_t)((x >> 1) | (x >> 2));

    r |= (r >> 2);
    r |= (r >> 4);
    return (r + 1) >> 1;
}

/* return the inverse of the finite field element x */

static uint8_t gf_inv(const uint8_t x)
{   uint8_t p1 = x, p2 = BPOLY, n1 = hibit(x), n2 = 0x80, v1 = 1, v2 = 0;

    if(x < 2)
        return x;

    for( ; ; )
    {
        if(n1)
            while(n2 >= n1)             /* divide polynomial p2 by p1    */
            {
                n2 /= n1;               /* shift smaller polynomial left */
                p2 ^= (p1 * n2) & 0xff; /* and remove from larger one    */
                v2 ^= (v1 * n2);        /* shift accumulated value and   */
                n2 = hibit(p2);         /* add into result               */
            }
        else
            return v1;

        if(n2)                          /* repeat with values swapped    */
            while(n1 >= n2)
            {
                n1 /= n2;
                p1 ^= p2 * n1;
                v1 ^= v2 * n1;
                n1 = hibit(p1);
            }
        else
            return v2;
    }
}

/* The forward and inverse affine transformations used in the S-box */
static uint8_t fwd_affine(const uint8_t x)
{
#if defined( HAVE_UINT_32T )
    uint32_t w = x;
    w ^= (w << 1) ^ (w << 2) ^ (w << 3) ^ (w << 4);
    return 0x63 ^ ((w ^ (w >> 8)) & 0xff);
#else
    return 0x63 ^ x ^ (x << 1) ^ (x << 2) ^ (x << 3) ^ (x << 4)
                    ^ (x >> 7) ^ (x >> 6) ^ (x >> 5) ^ (x >> 4);
#endif
}

static uint8_t inv_affine(const uint8_t x)
{
#if defined( HAVE_UINT_32T )
    uint32_t w = x;
    w = (w << 1) ^ (w << 3) ^ (w << 6);
    return 0x05 ^ ((w ^ (w >> 8)) & 0xff);
#else
    return 0x05 ^ (x << 1) ^ (x << 3) ^ (x << 6)
                ^ (x >> 7) ^ (x >> 5) ^ (x >> 2);
#endif
}

#define s_box(x)   fwd_affine(gf_inv(x))
#define is_box(x)  gf_inv(inv_affine(x))
#define gfm2_sb(x) f2(s_box(x))
#define gfm3_sb(x) f3(s_box(x))
#define gfm_9(x)   f9(x)
#define gfm_b(x)   fb(x)
#define gfm_d(x)   fd(x)
#define gfm_e(x)   fe(x)

#endif

#if defined( HAVE_MEMCPY )
#  define block_copy_nn(d, s, l)    memcpy(d, s, l)
#  define block_copy(d, s)          memcpy(d, s, N_BLOCK)
#else
#  define block_copy_nn(d, s, l)    copy_block_nn(d, s, l)
#  define block_copy(d, s)          copy_block(d, s)
#endif

static void copy_block( void *d, const void *s )
{
#if defined( HAVE_UINT_32T )
    ((uint32_t*)d)[ 0] = ((uint32_t*)s)[ 0];
    ((uint32_t*)d)[ 1] = ((uint32_t*)s)[ 1];
    ((uint32_t*)d)[ 2] = ((uint32_t*)s)[ 2];
    ((uint32_t*)d)[ 3] = ((uint32_t*)s)[ 3];
#else
    ((uint8_t*)d)[ 0] = ((uint8_t*)s)[ 0];
    ((uint8_t*)d)[ 1] = ((uint8_t*)s)[ 1];
    ((uint8_t*)d)[ 2] = ((uint8_t*)s)[ 2];
    ((uint8_t*)d)[ 3] = ((uint8_t*)s)[ 3];
    ((uint8_t*)d)[ 4] = ((uint8_t*)s)[ 4];
    ((uint8_t*)d)[ 5] = ((uint8_t*)s)[ 5];
    ((uint8_t*)d)[ 6] = ((uint8_t*)s)[ 6];
    ((uint8_t*)d)[ 7] = ((uint8_t*)s)[ 7];
    ((uint8_t*)d)[ 8] = ((uint8_t*)s)[ 8];
    ((uint8_t*)d)[ 9] = ((uint8_t*)s)[ 9];
    ((uint8_t*)d)[10] = ((uint8_t*)s)[10];
    ((uint8_t*)d)[11] = ((uint8_t*)s)[11];
    ((uint8_t*)d)[12] = ((uint8_t*)s)[12];
    ((uint8_t*)d)[13] = ((uint8_t*)s)[13];
    ((uint8_t*)d)[14] = ((uint8_t*)s)[14];
    ((uint8_t*)d)[15] = ((uint8_t*)s)[15];
#endif
}

static void copy_block_nn( uint8_t * d, const uint8_t *s, uint8_t nn )
{
    while( nn-- )
        //*((uint8_t*)d)++ = *((uint8_t*)s)++;
        *d++ = *s++;
}

static void xor_block( void *d, const void *s )
{
#if defined( HAVE_UINT_32T )
    ((uint32_t*)d)[ 0] ^= ((uint32_t*)s)[ 0];
    ((uint32_t*)d)[ 1] ^= ((uint32_t*)s)[ 1];
    ((uint32_t*)d)[ 2] ^= ((uint32_t*)s)[ 2];
    ((uint32_t*)d)[ 3] ^= ((uint32_t*)s)[ 3];
#else
    ((uint8_t*)d)[ 0] ^= ((uint8_t*)s)[ 0];
    ((uint8_t*)d)[ 1] ^= ((uint8_t*)s)[ 1];
    ((uint8_t*)d)[ 2] ^= ((uint8_t*)s)[ 2];
    ((uint8_t*)d)[ 3] ^= ((uint8_t*)s)[ 3];
    ((uint8_t*)d)[ 4] ^= ((uint8_t*)s)[ 4];
    ((uint8_t*)d)[ 5] ^= ((uint8_t*)s)[ 5];
    ((uint8_t*)d)[ 6] ^= ((uint8_t*)s)[ 6];
    ((uint8_t*)d)[ 7] ^= ((uint8_t*)s)[ 7];
    ((uint8_t*)d)[ 8] ^= ((uint8_t*)s)[ 8];
    ((uint8_t*)d)[ 9] ^= ((uint8_t*)s)[ 9];
    ((uint8_t*)d)[10] ^= ((uint8_t*)s)[10];
    ((uint8_t*)d)[11] ^= ((uint8_t*)s)[11];
    ((uint8_t*)d)[12] ^= ((uint8_t*)s)[12];
    ((uint8_t*)d)[13] ^= ((uint8_t*)s)[13];
    ((uint8_t*)d)[14] ^= ((uint8_t*)s)[14];
    ((uint8_t*)d)[15] ^= ((uint8_t*)s)[15];
#endif
}

static void copy_and_key( void *d, const void *s, const void *k )
{
#if defined( HAVE_UINT_32T )
    ((uint32_t*)d)[ 0] = ((uint32_t*)s)[ 0] ^ ((uint32_t*)k)[ 0];
    ((uint32_t*)d)[ 1] = ((uint32_t*)s)[ 1] ^ ((uint32_t*)k)[ 1];
    ((uint32_t*)d)[ 2] = ((uint32_t*)s)[ 2] ^ ((uint32_t*)k)[ 2];
    ((uint32_t*)d)[ 3] = ((uint32_t*)s)[ 3] ^ ((uint32_t*)k)[ 3];
#elif 1
    ((uint8_t*)d)[ 0] = ((uint8_t*)s)[ 0] ^ ((uint8_t*)k)[ 0];
    ((uint8_t*)d)[ 1] = ((uint8_t*)s)[ 1] ^ ((uint8_t*)k)[ 1];
    ((uint8_t*)d)[ 2] = ((uint8_t*)s)[ 2] ^ ((uint8_t*)k)[ 2];
    ((uint8_t*)d)[ 3] = ((uint8_t*)s)[ 3] ^ ((uint8_t*)k)[ 3];
    ((uint8_t*)d)[ 4] = ((uint8_t*)s)[ 4] ^ ((uint8_t*)k)[ 4];
    ((uint8_t*)d)[ 5] = ((uint8_t*)s)[ 5] ^ ((uint8_t*)k)[ 5];
    ((uint8_t*)d)[ 6] = ((uint8_t*)s)[ 6] ^ ((uint8_t*)k)[ 6];
    ((uint8_t*)d)[ 7] = ((uint8_t*)s)[ 7] ^ ((uint8_t*)k)[ 7];
    ((uint8_t*)d)[ 8] = ((uint8_t*)s)[ 8] ^ ((uint8_t*)k)[ 8];
    ((uint8_t*)d)[ 9] = ((uint8_t*)s)[ 9] ^ ((uint8_t*)k)[ 9];
    ((uint8_t*)d)[10] = ((uint8_t*)s)[10] ^ ((uint8_t*)k)[10];
    ((uint8_t*)d)[11] = ((uint8_t*)s)[11] ^ ((uint8_t*)k)[11];
    ((uint8_t*)d)[12] = ((uint8_t*)s)[12] ^ ((uint8_t*)k)[12];
    ((uint8_t*)d)[13] = ((uint8_t*)s)[13] ^ ((uint8_t*)k)[13];
    ((uint8_t*)d)[14] = ((uint8_t*)s)[14] ^ ((uint8_t*)k)[14];
    ((uint8_t*)d)[15] = ((uint8_t*)s)[15] ^ ((uint8_t*)k)[15];
#else
    block_copy(d, s);
    xor_block(d, k);
#endif
}

static void add_round_key( uint8_t d[N_BLOCK], const uint8_t k[N_BLOCK] )
{
    xor_block(d, k);
}

static void shift_sub_rows( uint8_t st[N_BLOCK] )
{   uint8_t tt;

    st[ 0] = s_box(st[ 0]); st[ 4] = s_box(st[ 4]);
    st[ 8] = s_box(st[ 8]); st[12] = s_box(st[12]);

    tt = st[1]; st[ 1] = s_box(st[ 5]); st[ 5] = s_box(st[ 9]);
    st[ 9] = s_box(st[13]); st[13] = s_box( tt );

    tt = st[2]; st[ 2] = s_box(st[10]); st[10] = s_box( tt );
    tt = st[6]; st[ 6] = s_box(st[14]); st[14] = s_box( tt );

    tt = st[15]; st[15] = s_box(st[11]); st[11] = s_box(st[ 7]);
    st[ 7] = s_box(st[ 3]); st[ 3] = s_box( tt );
}

#if defined( AES_DEC_PREKEYED )

static void inv_shift_sub_rows( uint8_t st[N_BLOCK] )
{   uint8_t tt;

    st[ 0] = is_box(st[ 0]); st[ 4] = is_box(st[ 4]);
    st[ 8] = is_box(st[ 8]); st[12] = is_box(st[12]);

    tt = st[13]; st[13] = is_box(st[9]); st[ 9] = is_box(st[5]);
    st[ 5] = is_box(st[1]); st[ 1] = is_box( tt );

    tt = st[2]; st[ 2] = is_box(st[10]); st[10] = is_box( tt );
    tt = st[6]; st[ 6] = is_box(st[14]); st[14] = is_box( tt );

    tt = st[3]; st[ 3] = is_box(st[ 7]); st[ 7] = is_box(st[11]);
    st[11] = is_box(st[15]); st[15] = is_box( tt );
}

#endif

#if defined( VERSION_1 )
  static void mix_sub_columns( uint8_t dt[N_BLOCK] )
  { uint8_t st[N_BLOCK];
    block_copy(st, dt);
#else
  static void mix_sub_columns( uint8_t dt[N_BLOCK], uint8_t st[N_BLOCK] )
  {
#endif
    dt[ 0] = gfm2_sb(st[0]) ^ gfm3_sb(st[5]) ^ s_box(st[10]) ^ s_box(st[15]);
    dt[ 1] = s_box(st[0]) ^ gfm2_sb(st[5]) ^ gfm3_sb(st[10]) ^ s_box(st[15]);
    dt[ 2] = s_box(st[0]) ^ s_box(st[5]) ^ gfm2_sb(st[10]) ^ gfm3_sb(st[15]);
    dt[ 3] = gfm3_sb(st[0]) ^ s_box(st[5]) ^ s_box(st[10]) ^ gfm2_sb(st[15]);

    dt[ 4] = gfm2_sb(st[4]) ^ gfm3_sb(st[9]) ^ s_box(st[14]) ^ s_box(st[3]);
    dt[ 5] = s_box(st[4]) ^ gfm2_sb(st[9]) ^ gfm3_sb(st[14]) ^ s_box(st[3]);
    dt[ 6] = s_box(st[4]) ^ s_box(st[9]) ^ gfm2_sb(st[14]) ^ gfm3_sb(st[3]);
    dt[ 7] = gfm3_sb(st[4]) ^ s_box(st[9]) ^ s_box(st[14]) ^ gfm2_sb(st[3]);

    dt[ 8] = gfm2_sb(st[8]) ^ gfm3_sb(st[13]) ^ s_box(st[2]) ^ s_box(st[7]);
    dt[ 9] = s_box(st[8]) ^ gfm2_sb(st[13]) ^ gfm3_sb(st[2]) ^ s_box(st[7]);
    dt[10] = s_box(st[8]) ^ s_box(st[13]) ^ gfm2_sb(st[2]) ^ gfm3_sb(st[7]);
    dt[11] = gfm3_sb(st[8]) ^ s_box(st[13]) ^ s_box(st[2]) ^ gfm2_sb(st[7]);

    dt[12] = gfm2_sb(st[12]) ^ gfm3_sb(st[1]) ^ s_box(st[6]) ^ s_box(st[11]);
    dt[13] = s_box(st[12]) ^ gfm2_sb(st[1]) ^ gfm3_sb(st[6]) ^ s_box(st[11]);
    dt[14] = s_box(st[12]) ^ s_box(st[1]) ^ gfm2_sb(st[6]) ^ gfm3_sb(st[11]);
    dt[15] = gfm3_sb(st[12]) ^ s_box(st[1]) ^ s_box(st[6]) ^ gfm2_sb(st[11]);
  }

#if defined( AES_DEC_PREKEYED )

#if defined( VERSION_1 )
  static void inv_mix_sub_columns( uint8_t dt[N_BLOCK] )
  { uint8_t st[N_BLOCK];
    block_copy(st, dt);
#else
  static void inv_mix_sub_columns( uint8_t dt[N_BLOCK], uint8_t st[N_BLOCK] )
  {
#endif
    dt[ 0] = is_box(gfm_e(st[ 0]) ^ gfm_b(st[ 1]) ^ gfm_d(st[ 2]) ^ gfm_9(st[ 3]));
    dt[ 5] = is_box(gfm_9(st[ 0]) ^ gfm_e(st[ 1]) ^ gfm_b(st[ 2]) ^ gfm_d(st[ 3]));
    dt[10] = is_box(gfm_d(st[ 0]) ^ gfm_9(st[ 1]) ^ gfm_e(st[ 2]) ^ gfm_b(st[ 3]));
    dt[15] = is_box(gfm_b(st[ 0]) ^ gfm_d(st[ 1]) ^ gfm_9(st[ 2]) ^ gfm_e(st[ 3]));

    dt[ 4] = is_box(gfm_e(st[ 4]) ^ gfm_b(st[ 5]) ^ gfm_d(st[ 6]) ^ gfm_9(st[ 7]));
    dt[ 9] = is_box(gfm_9(st[ 4]) ^ gfm_e(st[ 5]) ^ gfm_b(st[ 6]) ^ gfm_d(st[ 7]));
    dt[14] = is_box(gfm_d(st[ 4]) ^ gfm_9(st[ 5]) ^ gfm_e(st[ 6]) ^ gfm_b(st[ 7]));
    dt[ 3] = is_box(gfm_b(st[ 4]) ^ gfm_d(st[ 5]) ^ gfm_9(st[ 6]) ^ gfm_e(st[ 7]));

    dt[ 8] = is_box(gfm_e(st[ 8]) ^ gfm_b(st[ 9]) ^ gfm_d(st[10]) ^ gfm_9(st[11]));
    dt[13] = is_box(gfm_9(st[ 8]) ^ gfm_e(st[ 9]) ^ gfm_b(st[10]) ^ gfm_d(st[11]));
    dt[ 2] = is_box(gfm_d(st[ 8]) ^ gfm_9(st[ 9]) ^ gfm_e(st[10]) ^ gfm_b(st[11]));
    dt[ 7] = is_box(gfm_b(st[ 8]) ^ gfm_d(st[ 9]) ^ gfm_9(st[10]) ^ gfm_e(st[11]));

    dt[12] = is_box(gfm_e(st[12]) ^ gfm_b(st[13]) ^ gfm_d(st[14]) ^ gfm_9(st[15]));
    dt[ 1] = is_box(gfm_9(st[12]) ^ gfm_e(st[13]) ^ gfm_b(st[14]) ^ gfm_d(st[15]));
    dt[ 6] = is_box(gfm_d(st[12]) ^ gfm_9(st[13]) ^ gfm_e(st[14]) ^ gfm_b(st[15]));
    dt[11] = is_box(gfm_b(st[12]) ^ gfm_d(st[13]) ^ gfm_9(st[14]) ^ gfm_e(st[15]));
  }

#endif

#if defined( AES_ENC_PREKEYED ) || defined( AES_DEC_PREKEYED )

/*  Set the cipher key for the pre-keyed version */

return_type lorawan_aes_set_key( const uint8_t key[], length_type keylen, lorawan_aes_context ctx[1] )
{
    uint8_t cc, rc, hi;

    switch( keylen )
    {
    case 16:
    case 24:
    case 32:
        break;
    default:
        ctx->rnd = 0;
        return ( uint8_t )-1;
    }
    block_copy_nn(ctx->ksch, key, keylen);
    hi = (keylen + 28) << 2;
    ctx->rnd = (hi >> 4) - 1;
    for( cc = keylen, rc = 1; cc < hi; cc += 4 )
    {   uint8_t tt, t0, t1, t2, t3;

        t0 = ctx->ksch[cc - 4];
        t1 = ctx->ksch[cc - 3];
        t2 = ctx->ksch[cc - 2];
        t3 = ctx->ksch[cc - 1];
        if( cc % keylen == 0 )
        {
            tt = t0;
            t0 = s_box(t1) ^ rc;
            t1 = s_box(t2);
            t2 = s_box(t3);
            t3 = s_box(tt);
            rc = f2(rc);
        }
        else if( keylen > 24 && cc % keylen == 16 )
        {
            t0 = s_box(t0);
            t1 = s_box(t1);
            t2 = s_box(t2);
            t3 = s_box(t3);
        }
        tt = cc - keylen;
        ctx->ksch[cc + 0] = ctx->ksch[tt + 0] ^ t0;
        ctx->ksch[cc + 1] = ctx->ksch[tt + 1] ^ t1;
        ctx->ksch[cc + 2] = ctx->ksch[tt + 2] ^ t2;
        ctx->ksch[cc + 3] = ctx->ksch[tt + 3] ^ t3;
    }
    return 0;
}

#endif

#if defined( AES_ENC_PREKEYED )

/*  Encrypt a single block of 16 bytes */

return_type lorawan_aes_encrypt( const uint8_t in[N_BLOCK], uint8_t  out[N_BLOCK], const lorawan_aes_context ctx[1] )
{
    if( ctx->rnd )
    {
        uint8_t s1[N_BLOCK], r;
        copy_and_key( s1, in, ctx->ksch );

        for( r = 1 ; r < ctx->rnd ; ++r )
#if defined( VERSION_1 )
        {
            mix_sub_columns( s1 );
            add_round_key( s1, ctx->ksch + r * N_BLOCK);
        }
#else
        {   uint8_t s2[N_BLOCK];
            mix_sub_columns( s2, s1 );
            copy_and_key( s1, s2, ctx->ksch + r * N_BLOCK);
        }
#endif
        shift_sub_rows( s1 );
        copy_and_key( out, s1, ctx->ksch + r * N_BLOCK );
    }
    else
        return ( uint8_t )-1;
    return 0;
}

/* CBC encrypt a number of blocks (input and return an IV) */

return_type lorawan_aes_cbc_encrypt( const uint8_t *in, uint8_t *out,
                         int32_t n_block, uint8_t iv[N_BLOCK], const lorawan_aes_context ctx[1] )
{

    while(n_block--)
    {
        xor_block(iv, in);
        if(lorawan_aes_encrypt(iv, iv, ctx) != EXIT_SUCCESS)
            return EXIT_FAILURE;
        //memcpy(out, iv, N_BLOCK);
        block_copy(out, iv);
        in += N_BLOCK;
        out += N_BLOCK;
    }
    return EXIT_SUCCESS;
}

#endif

#if defined( AES_DEC_PREKEYED )

/*  Decrypt a single block of 16 bytes */

return_type lorawan_aes_decrypt( const uint8_t in[N_BLOCK], uint8_t out[N_BLOCK], const lorawan_aes_context ctx[1] )
{
    if( ctx->rnd )
    {
        uint8_t s1[N_BLOCK], r;
        copy_and_key( s1, in, ctx->ksch + ctx->rnd * N_BLOCK );
        inv_shift_sub_rows( s1 );

        for( r = ctx->rnd ; --r ; )
#if defined( VERSION_1 )
        {
            add_round_key( s1, ctx->ksch + r * N_BLOCK );
            inv_mix_sub_columns( s1 );
        }
#else
        {   uint8_t s2[N_BLOCK];
            copy_and_key( s2, s1, ctx->ksch + r * N_BLOCK );
            inv_mix_sub_columns( s1, s2 );
        }
#endif
        copy_and_key( out, s1, ctx->ksch );
    }
    else
        return -1;
    return 0;
}

/* CBC decrypt a number of blocks (input and return an IV) */

return_type lorawan_aes_cbc_decrypt( const uint8_t *in, uint8_t *out,
                         int32_t n_block, uint8_t iv[N_BLOCK], const lorawan_aes_context ctx[1] )
{
    while(n_block--)
    {   uint8_t tmp[N_BLOCK];

        //memcpy(tmp, in, N_BLOCK);
        block_copy(tmp, in);
        if(lorawan_aes_decrypt(in, out, ctx) != EXIT_SUCCESS)
            return EXIT_FAILURE;
        xor_block(out, iv);
        //memcpy(iv, tmp, N_BLOCK);
        block_copy(iv, tmp);
        in += N_BLOCK;
        out += N_BLOCK;
    }
    return EXIT_SUCCESS;
}

#endif

#if defined( AES_ENC_128_OTFK )

/*  The 'on the fly' encryption key update for for 128 bit keys */

static void update_encrypt_key_128( uint8_t k[N_BLOCK], uint8_t *rc )
{   uint8_t cc;

    k[0] ^= s_box(k[13]) ^ *rc;
    k[1] ^= s_box(k[14]);
    k[2] ^= s_box(k[15]);
    k[3] ^= s_box(k[12]);
    *rc = f2( *rc );

    for(cc = 4; cc < 16; cc += 4 )
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }
}

/*  Encrypt a single block of 16 bytes with 'on the fly' 128 bit keying */

void lorawan_aes_encrypt_128( const uint8_t in[N_BLOCK], uint8_t out[N_BLOCK],
                     const uint8_t key[N_BLOCK], uint8_t o_key[N_BLOCK] )
{   uint8_t s1[N_BLOCK], r, rc = 1;

    if(o_key != key)
        block_copy( o_key, key );
    copy_and_key( s1, in, o_key );

    for( r = 1 ; r < 10 ; ++r )
#if defined( VERSION_1 )
    {
        mix_sub_columns( s1 );
        update_encrypt_key_128( o_key, &rc );
        add_round_key( s1, o_key );
    }
#else
    {   uint8_t s2[N_BLOCK];
        mix_sub_columns( s2, s1 );
        update_encrypt_key_128( o_key, &rc );
        copy_and_key( s1, s2, o_key );
    }
#endif

    shift_sub_rows( s1 );
    update_encrypt_key_128( o_key, &rc );
    copy_and_key( out, s1, o_key );
}

#endif

#if defined( AES_DEC_128_OTFK )

/*  The 'on the fly' decryption key update for for 128 bit keys */

static void update_decrypt_key_128( uint8_t k[N_BLOCK], uint8_t *rc )
{   uint8_t cc;

    for( cc = 12; cc > 0; cc -= 4 )
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }
    *rc = d2(*rc);
    k[0] ^= s_box(k[13]) ^ *rc;
    k[1] ^= s_box(k[14]);
    k[2] ^= s_box(k[15]);
    k[3] ^= s_box(k[12]);
}

/*  Decrypt a single block of 16 bytes with 'on the fly' 128 bit keying */

void lorawan_aes_decrypt_128( const uint8_t in[N_BLOCK], uint8_t out[N_BLOCK],
                      const uint8_t key[N_BLOCK], uint8_t o_key[N_BLOCK] )
{
    uint8_t s1[N_BLOCK], r, rc = 0x6c;
    if(o_key != key)
        block_copy( o_key, key );

    copy_and_key( s1, in, o_key );
    inv_shift_sub_rows( s1 );

    for( r = 10 ; --r ; )
#if defined( VERSION_1 )
    {
        update_decrypt_key_128( o_key, &rc );
        add_round_key( s1, o_key );
        inv_mix_sub_columns( s1 );
    }
#else
    {   uint8_t s2[N_BLOCK];
        update_decrypt_key_128( o_key, &rc );
        copy_and_key( s2, s1, o_key );
        inv_mix_sub_columns( s1, s2 );
    }
#endif
    update_decrypt_key_128( o_key, &rc );
    copy_and_key( out, s1, o_key );
}

#endif

#if defined( AES_ENC_256_OTFK )

/*  The 'on the fly' encryption key update for for 256 bit keys */

static void update_encrypt_key_256( uint8_t k[2 * N_BLOCK], uint8_t *rc )
{   uint8_t cc;

    k[0] ^= s_box(k[29]) ^ *rc;
    k[1] ^= s_box(k[30]);
    k[2] ^= s_box(k[31]);
    k[3] ^= s_box(k[28]);
    *rc = f2( *rc );

    for(cc = 4; cc < 16; cc += 4)
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }

    k[16] ^= s_box(k[12]);
    k[17] ^= s_box(k[13]);
    k[18] ^= s_box(k[14]);
    k[19] ^= s_box(k[15]);

    for( cc = 20; cc < 32; cc += 4 )
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }
}

/*  Encrypt a single block of 16 bytes with 'on the fly' 256 bit keying */

void lorawan_aes_encrypt_256( const uint8_t in[N_BLOCK], uint8_t out[N_BLOCK],
                      const uint8_t key[2 * N_BLOCK], uint8_t o_key[2 * N_BLOCK] )
{
    uint8_t s1[N_BLOCK], r, rc = 1;
    if(o_key != key)
    {
        block_copy( o_key, key );
        block_copy( o_key + 16, key + 16 );
    }
    copy_and_key( s1, in, o_key );

    for( r = 1 ; r < 14 ; ++r )
#if defined( VERSION_1 )
    {
        mix_sub_columns(s1);
        if( r & 1 )
            add_round_key( s1, o_key + 16 );
        else
        {
            update_encrypt_key_256( o_key, &rc );
            add_round_key( s1, o_key );
        }
    }
#else
    {   uint8_t s2[N_BLOCK];
        mix_sub_columns( s2, s1 );
        if( r & 1 )
            copy_and_key( s1, s2, o_key + 16 );
        else
        {
            update_encrypt_key_256( o_key, &rc );
            copy_and_key( s1, s2, o_key );
        }
    }
#endif

    shift_sub_rows( s1 );
    update_encrypt_key_256( o_key, &rc );
    copy_and_key( out, s1, o_key );
}

#endif

#if defined( AES_DEC_256_OTFK )

/*  The 'on the fly' encryption key update for for 256 bit keys */

static void update_decrypt_key_256( uint8_t k[2 * N_BLOCK], uint8_t *rc )
{   uint8_t cc;

    for(cc = 28; cc > 16; cc -= 4)
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }

    k[16] ^= s_box(k[12]);
    k[17] ^= s_box(k[13]);
    k[18] ^= s_box(k[14]);
    k[19] ^= s_box(k[15]);

    for(cc = 12; cc > 0; cc -= 4)
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }

    *rc = d2(*rc);
    k[0] ^= s_box(k[29]) ^ *rc;
    k[1] ^= s_box(k[30]);
    k[2] ^= s_box(k[31]);
    k[3] ^= s_box(k[28]);
}

/*  Decrypt a single block of 16 bytes with 'on the fly'
    256 bit keying
*/
void lorawan_aes_decrypt_256( const uint8_t in[N_BLOCK], uint8_t out[N_BLOCK],
                      const uint8_t key[2 * N_BLOCK], uint8_t o_key[2 * N_BLOCK] )
{
    uint8_t s1[N_BLOCK], r, rc = 0x80;

    if(o_key != key)
    {
        block_copy( o_key, key );
        block_copy( o_key + 16, key + 16 );
    }

    copy_and_key( s1, in, o_key );
    inv_shift_sub_rows( s1 );

    for( r = 14 ; --r ; )
#if defined( VERSION_1 )
    {
        if( ( r & 1 ) )
        {
            update_decrypt_key_256( o_key, &rc );
            add_round_key( s1, o_key + 16 );
        }
        else
            add_round_key( s1, o_key );
        inv_mix_sub_columns( s1 );
    }
#else
    {   uint8_t s2[N_BLOCK];
        if( ( r & 1 ) )
        {
            update_decrypt_key_256( o_key, &rc );
            copy_and_key( s2, s1, o_key + 16 );
        }
        else
            copy_and_key( s2, s1, o_key );
        inv_mix_sub_columns( s1, s2 );
    }
#endif
    copy_and_key( out, s1, o_key );
}

#endif
