security.cpp

/*****************************************************************************
*
*  security.c  - CC3000 Host Driver Implementation.
*  Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*    Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
*    Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the   
*    distribution.
*
*    Neither the name of Texas Instruments Incorporated nor the names of
*    its contributors may be used to endorse or promote products derived
*    from this software without specific prior written permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
*  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
*  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
*  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
*  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
*  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
*  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
*  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
*  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
*  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
*  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*****************************************************************************/

//*****************************************************************************
//
//! \addtogroup security_api
//! @{
//
//*****************************************************************************

#include <avr/pgmspace.h>

#include "security.hpp"

#ifndef CC3000_UNENCRYPTED_SMART_CONFIG
#ifndef __ENABLE_MULTITHREADED_SUPPORT__
#define c_nvmem_read nvmem_read
#define c_nvmem_write nvmem_write
#endif /* __ENABLE_MULTITHREADED_SUPPORT__ */
// foreward sbox
const unsigned char sbox[256] PROGMEM = { 
//0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, //0
0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, //1
0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, //2
0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, //3
0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, //4
0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, //5
0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, //6
0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, //7
0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, //8
0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, //9
0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, //A
0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, //B
0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, //C
0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, //D
0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, //E
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; //F   
// inverse sbox
const unsigned char rsbox[256] PROGMEM =
{ 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb
, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb
, 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e
, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25
, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92
, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84
, 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06
, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b
, 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73
, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e
, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b
, 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4
, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f
, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef
, 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61
, 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };
// round constant
const unsigned char Rcon[11] PROGMEM = {
  0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36};


unsigned char expandedKey[176];

//*****************************************************************************
//
//!  expandKey
//!
//!  @param  key          AES128 key - 16 bytes
//!  @param  expandedKey  expanded AES128 key
//!
//!  @return  none
//!
//!  @brief  expend a 16 bytes key for AES128 implementation
//!
//*****************************************************************************

static void expandKey(unsigned char *expandedKey,
               unsigned char *key)
{
  unsigned short ii, buf1;
  for (ii=0;ii<16;ii++)
    expandedKey[ii] = key[ii];
  for (ii=1;ii<11;ii++){
    buf1 = expandedKey[ii*16 - 4];
    expandedKey[ii*16 + 0] = sbox[expandedKey[ii*16 - 3]]^expandedKey[(ii-1)*16 + 0]^Rcon[ii];
    expandedKey[ii*16 + 1] = sbox[expandedKey[ii*16 - 2]]^expandedKey[(ii-1)*16 + 1];
    expandedKey[ii*16 + 2] = sbox[expandedKey[ii*16 - 1]]^expandedKey[(ii-1)*16 + 2];
    expandedKey[ii*16 + 3] = sbox[buf1                  ]^expandedKey[(ii-1)*16 + 3];
    expandedKey[ii*16 + 4] = expandedKey[(ii-1)*16 + 4]^expandedKey[ii*16 + 0];
    expandedKey[ii*16 + 5] = expandedKey[(ii-1)*16 + 5]^expandedKey[ii*16 + 1];
    expandedKey[ii*16 + 6] = expandedKey[(ii-1)*16 + 6]^expandedKey[ii*16 + 2];
    expandedKey[ii*16 + 7] = expandedKey[(ii-1)*16 + 7]^expandedKey[ii*16 + 3];
    expandedKey[ii*16 + 8] = expandedKey[(ii-1)*16 + 8]^expandedKey[ii*16 + 4];
    expandedKey[ii*16 + 9] = expandedKey[(ii-1)*16 + 9]^expandedKey[ii*16 + 5];
    expandedKey[ii*16 +10] = expandedKey[(ii-1)*16 +10]^expandedKey[ii*16 + 6];
    expandedKey[ii*16 +11] = expandedKey[(ii-1)*16 +11]^expandedKey[ii*16 + 7];
    expandedKey[ii*16 +12] = expandedKey[(ii-1)*16 +12]^expandedKey[ii*16 + 8];
    expandedKey[ii*16 +13] = expandedKey[(ii-1)*16 +13]^expandedKey[ii*16 + 9];
    expandedKey[ii*16 +14] = expandedKey[(ii-1)*16 +14]^expandedKey[ii*16 +10];
    expandedKey[ii*16 +15] = expandedKey[(ii-1)*16 +15]^expandedKey[ii*16 +11];
  }
	
}

//*****************************************************************************
//
//!  galois_mul2
//!
//!  @param  value    argument to multiply
//!
//!  @return  multiplied argument
//!
//!  @brief  multiply by 2 in the galois field
//!
//*****************************************************************************

static unsigned char galois_mul2(unsigned char value)
{
	if (value>>7)
	{
		value = value << 1;
		return (value^0x1b);
	} else
		return value<<1;
}

//*****************************************************************************
//
//!  aes_encr
//!
//!  @param[in]  expandedKey expanded AES128 key
//!  @param[in/out] state 16 bytes of plain text and cipher text
//!
//!  @return  none
//!
//!  @brief   internal implementation of AES128 encryption.
//!           straight forward aes encryption implementation
//!           first the group of operations
//!          - addRoundKey
//!          - subbytes
//!          - shiftrows
//!          - mixcolums
//!          is executed 9 times, after this addroundkey to finish the 9th 
//!          round, after that the 10th round without mixcolums
//!          no further subfunctions to save cycles for function calls
//!          no structuring with "for (....)" to save cycles.
//!	 
//!
//*****************************************************************************

static void aes_encr(unsigned char *state, unsigned char *expandedKey)
{
  unsigned char buf1, buf2, buf3, round;
		
  for (round = 0; round < 9; round ++){
    // addroundkey, sbox and shiftrows
    // row 0
    state[ 0]  = sbox[(state[ 0] ^ expandedKey[(round*16)     ])];
    state[ 4]  = sbox[(state[ 4] ^ expandedKey[(round*16) +  4])];
    state[ 8]  = sbox[(state[ 8] ^ expandedKey[(round*16) +  8])];
    state[12]  = sbox[(state[12] ^ expandedKey[(round*16) + 12])];
    // row 1
    buf1 = state[1] ^ expandedKey[(round*16) + 1];
    state[ 1]  = sbox[(state[ 5] ^ expandedKey[(round*16) +  5])];
    state[ 5]  = sbox[(state[ 9] ^ expandedKey[(round*16) +  9])];
    state[ 9]  = sbox[(state[13] ^ expandedKey[(round*16) + 13])];
    state[13]  = sbox[buf1];
    // row 2
    buf1 = state[2] ^ expandedKey[(round*16) + 2];
    buf2 = state[6] ^ expandedKey[(round*16) + 6];
    state[ 2]  = sbox[(state[10] ^ expandedKey[(round*16) + 10])];
    state[ 6]  = sbox[(state[14] ^ expandedKey[(round*16) + 14])];
    state[10]  = sbox[buf1];
    state[14]  = sbox[buf2];
    // row 3
    buf1 = state[15] ^ expandedKey[(round*16) + 15];
    state[15]  = sbox[(state[11] ^ expandedKey[(round*16) + 11])];
    state[11]  = sbox[(state[ 7] ^ expandedKey[(round*16) +  7])];
    state[ 7]  = sbox[(state[ 3] ^ expandedKey[(round*16) +  3])];
    state[ 3]  = sbox[buf1];
    
    // mixcolums //////////
    // col1
    buf1 = state[0] ^ state[1] ^ state[2] ^ state[3];
    buf2 = state[0];
    buf3 = state[0]^state[1]; buf3=galois_mul2(buf3); state[0] = state[0] ^ buf3 ^ buf1;
    buf3 = state[1]^state[2]; buf3=galois_mul2(buf3); state[1] = state[1] ^ buf3 ^ buf1;
    buf3 = state[2]^state[3]; buf3=galois_mul2(buf3); state[2] = state[2] ^ buf3 ^ buf1;
    buf3 = state[3]^buf2;     buf3=galois_mul2(buf3); state[3] = state[3] ^ buf3 ^ buf1;
    // col2
    buf1 = state[4] ^ state[5] ^ state[6] ^ state[7];
    buf2 = state[4];
    buf3 = state[4]^state[5]; buf3=galois_mul2(buf3); state[4] = state[4] ^ buf3 ^ buf1;
    buf3 = state[5]^state[6]; buf3=galois_mul2(buf3); state[5] = state[5] ^ buf3 ^ buf1;
    buf3 = state[6]^state[7]; buf3=galois_mul2(buf3); state[6] = state[6] ^ buf3 ^ buf1;
    buf3 = state[7]^buf2;     buf3=galois_mul2(buf3); state[7] = state[7] ^ buf3 ^ buf1;
    // col3
    buf1 = state[8] ^ state[9] ^ state[10] ^ state[11];
    buf2 = state[8];
    buf3 = state[8]^state[9];   buf3=galois_mul2(buf3); state[8] = state[8] ^ buf3 ^ buf1;
    buf3 = state[9]^state[10];  buf3=galois_mul2(buf3); state[9] = state[9] ^ buf3 ^ buf1;
    buf3 = state[10]^state[11]; buf3=galois_mul2(buf3); state[10] = state[10] ^ buf3 ^ buf1;
    buf3 = state[11]^buf2;      buf3=galois_mul2(buf3); state[11] = state[11] ^ buf3 ^ buf1;
    // col4
    buf1 = state[12] ^ state[13] ^ state[14] ^ state[15];
    buf2 = state[12];
    buf3 = state[12]^state[13]; buf3=galois_mul2(buf3); state[12] = state[12] ^ buf3 ^ buf1;
    buf3 = state[13]^state[14]; buf3=galois_mul2(buf3); state[13] = state[13] ^ buf3 ^ buf1;
    buf3 = state[14]^state[15]; buf3=galois_mul2(buf3); state[14] = state[14] ^ buf3 ^ buf1;
    buf3 = state[15]^buf2;      buf3=galois_mul2(buf3); state[15] = state[15] ^ buf3 ^ buf1;    
		
  }
  // 10th round without mixcols
  state[ 0]  = sbox[(state[ 0] ^ expandedKey[(round*16)     ])];
  state[ 4]  = sbox[(state[ 4] ^ expandedKey[(round*16) +  4])];
  state[ 8]  = sbox[(state[ 8] ^ expandedKey[(round*16) +  8])];
  state[12]  = sbox[(state[12] ^ expandedKey[(round*16) + 12])];
  // row 1
  buf1 = state[1] ^ expandedKey[(round*16) + 1];
  state[ 1]  = sbox[(state[ 5] ^ expandedKey[(round*16) +  5])];
  state[ 5]  = sbox[(state[ 9] ^ expandedKey[(round*16) +  9])];
  state[ 9]  = sbox[(state[13] ^ expandedKey[(round*16) + 13])];
  state[13]  = sbox[buf1];
  // row 2
  buf1 = state[2] ^ expandedKey[(round*16) + 2];
  buf2 = state[6] ^ expandedKey[(round*16) + 6];
  state[ 2]  = sbox[(state[10] ^ expandedKey[(round*16) + 10])];
  state[ 6]  = sbox[(state[14] ^ expandedKey[(round*16) + 14])];
  state[10]  = sbox[buf1];
  state[14]  = sbox[buf2];
  // row 3
  buf1 = state[15] ^ expandedKey[(round*16) + 15];
  state[15]  = sbox[(state[11] ^ expandedKey[(round*16) + 11])];
  state[11]  = sbox[(state[ 7] ^ expandedKey[(round*16) +  7])];
  state[ 7]  = sbox[(state[ 3] ^ expandedKey[(round*16) +  3])];
  state[ 3]  = sbox[buf1];
  // last addroundkey
  state[ 0]^=expandedKey[160];
  state[ 1]^=expandedKey[161];
  state[ 2]^=expandedKey[162];
  state[ 3]^=expandedKey[163];
  state[ 4]^=expandedKey[164];
  state[ 5]^=expandedKey[165];
  state[ 6]^=expandedKey[166];
  state[ 7]^=expandedKey[167];
  state[ 8]^=expandedKey[168];
  state[ 9]^=expandedKey[169];
  state[10]^=expandedKey[170];
  state[11]^=expandedKey[171];
  state[12]^=expandedKey[172];
  state[13]^=expandedKey[173];
  state[14]^=expandedKey[174]; 
  state[15]^=expandedKey[175];
} 

//*****************************************************************************
//
//!  aes_decr
//!
//!  @param[in]  expandedKey expanded AES128 key
//!  @param[in\out] state 16 bytes of cipher text and plain text
//!
//!  @return  none
//!
//!  @brief   internal implementation of AES128 decryption.
//!           straight forward aes decryption implementation
//!           the order of substeps is the exact reverse of decryption
//!           inverse functions:
//!            - addRoundKey is its own inverse
//!            - rsbox is inverse of sbox
//!            - rightshift instead of leftshift
//!            - invMixColumns = barreto + mixColumns
//!           no further subfunctions to save cycles for function calls
//!           no structuring with "for (....)" to save cycles
//!
//*****************************************************************************

static void aes_decr(unsigned char *state, unsigned char *expandedKey)
{
  unsigned char buf1, buf2, buf3;
  signed char round;
  round = 9;
	
  // initial addroundkey
  state[ 0]^=expandedKey[160];
  state[ 1]^=expandedKey[161];
  state[ 2]^=expandedKey[162];
  state[ 3]^=expandedKey[163];
  state[ 4]^=expandedKey[164];
  state[ 5]^=expandedKey[165];
  state[ 6]^=expandedKey[166];
  state[ 7]^=expandedKey[167];
  state[ 8]^=expandedKey[168];
  state[ 9]^=expandedKey[169];
  state[10]^=expandedKey[170];
  state[11]^=expandedKey[171];
  state[12]^=expandedKey[172];
  state[13]^=expandedKey[173];
  state[14]^=expandedKey[174]; 
  state[15]^=expandedKey[175];
	
  // 10th round without mixcols
  state[ 0]  = rsbox[state[ 0]] ^ expandedKey[(round*16)     ];
  state[ 4]  = rsbox[state[ 4]] ^ expandedKey[(round*16) +  4];
  state[ 8]  = rsbox[state[ 8]] ^ expandedKey[(round*16) +  8];
  state[12]  = rsbox[state[12]] ^ expandedKey[(round*16) + 12];
  // row 1
  buf1 =       rsbox[state[13]] ^ expandedKey[(round*16) +  1];
  state[13]  = rsbox[state[ 9]] ^ expandedKey[(round*16) + 13];
  state[ 9]  = rsbox[state[ 5]] ^ expandedKey[(round*16) +  9];
  state[ 5]  = rsbox[state[ 1]] ^ expandedKey[(round*16) +  5];
  state[ 1]  = buf1;
  // row 2
  buf1 =       rsbox[state[ 2]] ^ expandedKey[(round*16) + 10];
  buf2 =       rsbox[state[ 6]] ^ expandedKey[(round*16) + 14];
  state[ 2]  = rsbox[state[10]] ^ expandedKey[(round*16) +  2];
  state[ 6]  = rsbox[state[14]] ^ expandedKey[(round*16) +  6];
  state[10]  = buf1;
  state[14]  = buf2;
  // row 3
  buf1 =       rsbox[state[ 3]] ^ expandedKey[(round*16) + 15];
  state[ 3]  = rsbox[state[ 7]] ^ expandedKey[(round*16) +  3];
  state[ 7]  = rsbox[state[11]] ^ expandedKey[(round*16) +  7];
  state[11]  = rsbox[state[15]] ^ expandedKey[(round*16) + 11];
  state[15]  = buf1;
	
  for (round = 8; round >= 0; round--){
    // barreto
    //col1
    buf1 = galois_mul2(galois_mul2(state[0]^state[2]));
    buf2 = galois_mul2(galois_mul2(state[1]^state[3]));
    state[0] ^= buf1;     state[1] ^= buf2;    state[2] ^= buf1;    state[3] ^= buf2;
    //col2
    buf1 = galois_mul2(galois_mul2(state[4]^state[6]));
    buf2 = galois_mul2(galois_mul2(state[5]^state[7]));
    state[4] ^= buf1;    state[5] ^= buf2;    state[6] ^= buf1;    state[7] ^= buf2;
    //col3
    buf1 = galois_mul2(galois_mul2(state[8]^state[10]));
    buf2 = galois_mul2(galois_mul2(state[9]^state[11]));
    state[8] ^= buf1;    state[9] ^= buf2;    state[10] ^= buf1;    state[11] ^= buf2;
    //col4
    buf1 = galois_mul2(galois_mul2(state[12]^state[14]));
    buf2 = galois_mul2(galois_mul2(state[13]^state[15]));
    state[12] ^= buf1;    state[13] ^= buf2;    state[14] ^= buf1;    state[15] ^= buf2;
    // mixcolums //////////
    // col1
    buf1 = state[0] ^ state[1] ^ state[2] ^ state[3];
    buf2 = state[0];
    buf3 = state[0]^state[1]; buf3=galois_mul2(buf3); state[0] = state[0] ^ buf3 ^ buf1;
    buf3 = state[1]^state[2]; buf3=galois_mul2(buf3); state[1] = state[1] ^ buf3 ^ buf1;
    buf3 = state[2]^state[3]; buf3=galois_mul2(buf3); state[2] = state[2] ^ buf3 ^ buf1;
    buf3 = state[3]^buf2;     buf3=galois_mul2(buf3); state[3] = state[3] ^ buf3 ^ buf1;
    // col2
    buf1 = state[4] ^ state[5] ^ state[6] ^ state[7];
    buf2 = state[4];
    buf3 = state[4]^state[5]; buf3=galois_mul2(buf3); state[4] = state[4] ^ buf3 ^ buf1;
    buf3 = state[5]^state[6]; buf3=galois_mul2(buf3); state[5] = state[5] ^ buf3 ^ buf1;
    buf3 = state[6]^state[7]; buf3=galois_mul2(buf3); state[6] = state[6] ^ buf3 ^ buf1;
    buf3 = state[7]^buf2;     buf3=galois_mul2(buf3); state[7] = state[7] ^ buf3 ^ buf1;
    // col3
    buf1 = state[8] ^ state[9] ^ state[10] ^ state[11];
    buf2 = state[8];
    buf3 = state[8]^state[9];   buf3=galois_mul2(buf3); state[8] = state[8] ^ buf3 ^ buf1;
    buf3 = state[9]^state[10];  buf3=galois_mul2(buf3); state[9] = state[9] ^ buf3 ^ buf1;
    buf3 = state[10]^state[11]; buf3=galois_mul2(buf3); state[10] = state[10] ^ buf3 ^ buf1;
    buf3 = state[11]^buf2;      buf3=galois_mul2(buf3); state[11] = state[11] ^ buf3 ^ buf1;
    // col4
    buf1 = state[12] ^ state[13] ^ state[14] ^ state[15];
    buf2 = state[12];
    buf3 = state[12]^state[13]; buf3=galois_mul2(buf3); state[12] = state[12] ^ buf3 ^ buf1;
    buf3 = state[13]^state[14]; buf3=galois_mul2(buf3); state[13] = state[13] ^ buf3 ^ buf1;
    buf3 = state[14]^state[15]; buf3=galois_mul2(buf3); state[14] = state[14] ^ buf3 ^ buf1;
    buf3 = state[15]^buf2;      buf3=galois_mul2(buf3); state[15] = state[15] ^ buf3 ^ buf1;    
		
    // addroundkey, rsbox and shiftrows
    // row 0
    state[ 0]  = rsbox[state[ 0]] ^ expandedKey[(round*16)     ];
    state[ 4]  = rsbox[state[ 4]] ^ expandedKey[(round*16) +  4];
    state[ 8]  = rsbox[state[ 8]] ^ expandedKey[(round*16) +  8];
    state[12]  = rsbox[state[12]] ^ expandedKey[(round*16) + 12];
    // row 1
    buf1 =       rsbox[state[13]] ^ expandedKey[(round*16) +  1];
    state[13]  = rsbox[state[ 9]] ^ expandedKey[(round*16) + 13];
    state[ 9]  = rsbox[state[ 5]] ^ expandedKey[(round*16) +  9];
    state[ 5]  = rsbox[state[ 1]] ^ expandedKey[(round*16) +  5];
    state[ 1]  = buf1;
    // row 2
    buf1 =       rsbox[state[ 2]] ^ expandedKey[(round*16) + 10];
    buf2 =       rsbox[state[ 6]] ^ expandedKey[(round*16) + 14];
    state[ 2]  = rsbox[state[10]] ^ expandedKey[(round*16) +  2];
    state[ 6]  = rsbox[state[14]] ^ expandedKey[(round*16) +  6];
    state[10]  = buf1;
    state[14]  = buf2;
    // row 3
    buf1 =       rsbox[state[ 3]] ^ expandedKey[(round*16) + 15];
    state[ 3]  = rsbox[state[ 7]] ^ expandedKey[(round*16) +  3];
    state[ 7]  = rsbox[state[11]] ^ expandedKey[(round*16) +  7];
    state[11]  = rsbox[state[15]] ^ expandedKey[(round*16) + 11];
    state[15]  = buf1;
  }
	
} 

//*****************************************************************************
//
//!  aes_encrypt
//!
//!  @param[in]  key   AES128 key of size 16 bytes
//!  @param[in\out] state   16 bytes of plain text and cipher text
//!
//!  @return  none
//!
//!  @brief   AES128 encryption:
//!           Given AES128 key and  16 bytes plain text, cipher text of 16 bytes
//!           is computed. The AES implementation is in mode ECB (Electronic 
//!           Code Book). 
//!	 
//!
//*****************************************************************************
#ifdef __ENABLE_MULTITHREADED_SUPPORT__
void c_aes_encrypt(unsigned char *state, unsigned char *key)
#else /* __ENABLE_MULTITHREADED_SUPPORT__ */
void aes_encrypt(unsigned char *state, unsigned char *key)
#endif /* __ENABLE_MULTITHREADED_SUPPORT__ */
{
	// expand the key into 176 bytes
	expandKey(expandedKey, key);       
	aes_encr(state, expandedKey);
}

//*****************************************************************************
//
//!  aes_decrypt
//!
//!  @param[in]  key   AES128 key of size 16 bytes
//!  @param[in\out] state   16 bytes of cipher text and plain text
//!
//!  @return  none
//!
//!  @brief   AES128 decryption:
//!           Given AES128 key and  16 bytes cipher text, plain text of 16 bytes
//!           is computed The AES implementation is in mode ECB 
//!           (Electronic Code Book).
//!	 
//!
//*****************************************************************************
#ifdef __ENABLE_MULTITHREADED_SUPPORT__
void c_aes_decrypt(unsigned char *state, unsigned char *key)
#else /* __ENABLE_MULTITHREADED_SUPPORT__ */
void aes_decrypt(unsigned char *state, unsigned char *key)
#endif /* __ENABLE_MULTITHREADED_SUPPORT__ */
{
    expandKey(expandedKey, key);       // expand the key into 176 bytes
    aes_decr(state, expandedKey);
}

//*****************************************************************************
//
//!  aes_read_key
//!
//!  @param[out]  key   AES128 key of size 16 bytes
//!
//!  @return  on success 0, error otherwise.
//!
//!  @brief   Reads AES128 key from EEPROM
//!           Reads the AES128 key from fileID #12 in EEPROM
//!           returns an error if the key does not exist. 
//!	 
//!
//*****************************************************************************
#ifdef __ENABLE_MULTITHREADED_SUPPORT__
signed long c_aes_read_key(unsigned char *key)
#else /* __ENABLE_MULTITHREADED_SUPPORT__ */
signed long aes_read_key(unsigned char *key)
#endif /* __ENABLE_MULTITHREADED_SUPPORT__ */
{
	signed long	returnValue;
    returnValue = c_nvmem_read(NVMEM_AES128_KEY_FILEID, AES128_KEY_SIZE, 0, key);
	return returnValue;
}

//*****************************************************************************
//
//!  aes_write_key
//!
//!  @param[out]  key   AES128 key of size 16 bytes
//!
//!  @return  on success 0, error otherwise.
//!
//!  @brief   writes AES128 key from EEPROM
//!           Writes the AES128 key to fileID #12 in EEPROM
//!	 
//!
//*****************************************************************************

#ifdef __ENABLE_MULTITHREADED_SUPPORT__
signed long c_aes_write_key(unsigned char *key)
#else /* __ENABLE_MULTITHREADED_SUPPORT__ */
signed long aes_write_key(unsigned char *key)
#endif /* __ENABLE_MULTITHREADED_SUPPORT__ */
{
	signed long	returnValue;
    returnValue = c_nvmem_write(NVMEM_AES128_KEY_FILEID, AES128_KEY_SIZE, 0, key);
	return returnValue;
}

#endif //CC3000_UNENCRYPTED_SMART_CONFIG

//*****************************************************************************
//
// Close the Doxygen group.
//! @}
//
//*****************************************************************************