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esphome_elektromer_han/components/xt211/gxaes.c

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//
// --------------------------------------------------------------------------
// Gurux Ltd
//
//
//
// Filename: $HeadURL$
//
// Version: $Revision$,
// $Date$
// $Author$
//
// Copyright (c) Gurux Ltd
//
//---------------------------------------------------------------------------
//
// DESCRIPTION
//
// This file is a part of Gurux Device Framework.
//
// Gurux Device Framework is Open Source software; you can redistribute it
// and/or modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; version 2 of the License.
// Gurux Device Framework is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// This code is licensed under the GNU General Public License v2.
// Full text may be retrieved at http://www.gnu.org/licenses/gpl-2.0.txt
//---------------------------------------------------------------------------
#include "gxignore.h"
#ifndef DLMS_IGNORE_AES
#include <string.h> // CBC mode, for memset
#include <stdint.h>
#include "gxaes.h"
#if defined(USE_AVR) || defined(ARDUINO_ARCH_AVR)
//If AVR is used.
#include <avr/pgmspace.h>
#endif //#if defined(USE_AVR) || defined(ARDUINO_ARCH_AVR)
#define Nb 4
#define BLOCKLEN 16 //Block length in bytes AES is 128b block only
#if defined(AES256) && (AES256 == 1)
#define Nk 8
#define KEYLEN 32
#define Nr 14
#define keyExpSize 240
#elif defined(AES192) && (AES192 == 1)
#define Nk 6
#define KEYLEN 24
#define Nr 12
#define keyExpSize 208
#else
#define Nk 4 // The number of 32 bit words in a key.
#define KEYLEN 16 // Key length in bytes
#define Nr 10 // The number of rounds in AES Cipher.
#define keyExpSize 176
#endif
#ifndef MULTIPLY_AS_A_FUNCTION
#define MULTIPLY_AS_A_FUNCTION 0
#endif
// state - array holding the intermediate results during decryption.
typedef unsigned char state_t[4][4];
static state_t* state;
// The array that stores the round keys.
static unsigned char RoundKey[keyExpSize];
// The Key input to the AES Program
static const unsigned char* Key;
#if defined(CBC) && CBC
// Initial Vector used only for CBC mode
static unsigned char* Iv;
#endif
#ifndef USE_PROGMEM
static const unsigned char __SBOX[256] = {
#else
static const unsigned char __SBOX[256] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
//0 1 2 3 4 5 6 7 8 9 A B C D E F
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0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
#ifndef USE_PROGMEM
static const unsigned char __RS_BOX[256] = {
#else
static const unsigned char __RS_BOX[256] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
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// The round constant word array, Rcon[i], contains the values given by
// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
#ifndef USE_PROGMEM
static const unsigned char __R_CON[11] = {
#else
static const unsigned char __R_CON[11] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
#if 0
#ifndef USE_PROGMEM
static const unsigned char __R_CON[256] = {
#else
static const unsigned char __R_CON[256] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
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0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d };
#endif
static unsigned char getSBoxValue(unsigned char offset)
{
#ifdef ARDUINO_ARCH_AVR
//If Arduino is used data is read from flash like this.
return pgm_read_byte_near(__SBOX + offset);
#else
return __SBOX[offset];
#endif //ARDUINO_ARCH_AVR
}
static unsigned char getSBoxInvert(unsigned char offset)
{
#ifdef ARDUINO_ARCH_AVR
//If Arduino is used data is read from flash like this.
return pgm_read_byte_near(__RS_BOX + offset);
#else
return __RS_BOX[offset];
#endif //ARDUINO_ARCH_AVR
}
static unsigned char getRCon(unsigned char offset)
{
#ifdef ARDUINO_ARCH_AVR
//If Arduino is used data is read from flash like this.
return pgm_read_byte_near(__R_CON + offset);
#else
return __R_CON[offset];
#endif //ARDUINO_ARCH_AVR
}
// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
static void KeyExpansion(void)
{
unsigned char k;
uint32_t i;
// Used for the column/row operations
unsigned char tempa[4];
// The first round key is the key itself.
for (i = 0; i < Nk; ++i)
{
RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
}
// All other round keys are found from the previous round keys.
//i == Nk
for (; i < Nb * (Nr + 1); ++i)
{
{
tempa[0] = RoundKey[(i - 1) * 4 + 0];
tempa[1] = RoundKey[(i - 1) * 4 + 1];
tempa[2] = RoundKey[(i - 1) * 4 + 2];
tempa[3] = RoundKey[(i - 1) * 4 + 3];
}
if (i % Nk == 0)
{
// This function shifts the 4 bytes in a word to the left once.
// [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
// Function RotWord()
{
k = tempa[0];
tempa[0] = tempa[1];
tempa[1] = tempa[2];
tempa[2] = tempa[3];
tempa[3] = k;
}
// SubWord() is a function that takes a four-byte input word and
// applies the S-box to each of the four bytes to produce an output word.
// Function Subword()
{
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
}
tempa[0] = (unsigned char)(tempa[0] ^ getRCon((unsigned char)(i / Nk)));
}
#if defined(AES256) && (AES256 == 1)
if (i % Nk == 4)
{
// Function Subword()
{
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
}
}
#endif
RoundKey[i * 4 + 0] = RoundKey[(i - Nk) * 4 + 0] ^ tempa[0];
RoundKey[i * 4 + 1] = RoundKey[(i - Nk) * 4 + 1] ^ tempa[1];
RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2];
RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3];
}
}
// This function adds the round key to state.
// The round key is added to the state by an XOR function.
static void AddRoundKey(unsigned char round)
{
unsigned char i, j;
for (i = 0; i < 4; ++i)
{
for (j = 0; j < 4; ++j)
{
(*state)[i][j] ^= RoundKey[round * Nb * 4 + i * Nb + j];
}
}
}
// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
static void SubBytes(void)
{
unsigned char i, j;
for (i = 0; i < 4; ++i)
{
for (j = 0; j < 4; ++j)
{
(*state)[j][i] = getSBoxValue((*state)[j][i]);
}
}
}
// The ShiftRows() function shifts the rows in the state to the left.
// Each row is shifted with different offset.
// Offset = Row number. So the first row is not shifted.
static void ShiftRows(void)
{
unsigned char temp;
// Rotate first row 1 columns to left
temp = (*state)[0][1];
(*state)[0][1] = (*state)[1][1];
(*state)[1][1] = (*state)[2][1];
(*state)[2][1] = (*state)[3][1];
(*state)[3][1] = temp;
// Rotate second row 2 columns to left
temp = (*state)[0][2];
(*state)[0][2] = (*state)[2][2];
(*state)[2][2] = temp;
temp = (*state)[1][2];
(*state)[1][2] = (*state)[3][2];
(*state)[3][2] = temp;
// Rotate third row 3 columns to left
temp = (*state)[0][3];
(*state)[0][3] = (*state)[3][3];
(*state)[3][3] = (*state)[2][3];
(*state)[2][3] = (*state)[1][3];
(*state)[1][3] = temp;
}
static unsigned char xtime(unsigned char x)
{
return (unsigned char)((x << 1) ^ (((x >> 7) & 1) * 0x1b));
}
// MixColumns function mixes the columns of the state matrix
static void MixColumns(void)
{
unsigned char i;
unsigned char Tmp, Tm, t;
for (i = 0; i < 4; ++i)
{
t = (*state)[i][0];
Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3];
Tm = (*state)[i][0] ^ (*state)[i][1]; Tm = xtime(Tm); (*state)[i][0] ^= Tm ^ Tmp;
Tm = (*state)[i][1] ^ (*state)[i][2]; Tm = xtime(Tm); (*state)[i][1] ^= Tm ^ Tmp;
Tm = (*state)[i][2] ^ (*state)[i][3]; Tm = xtime(Tm); (*state)[i][2] ^= Tm ^ Tmp;
Tm = (*state)[i][3] ^ t; Tm = xtime(Tm); (*state)[i][3] ^= Tm ^ Tmp;
}
}
// Multiply is used to multiply numbers in the field GF(2^8)
#if MULTIPLY_AS_A_FUNCTION
static unsigned char Multiply(unsigned char x, unsigned char y)
{
return (((y & 1) * x) ^
((y >> 1 & 1) * xtime(x)) ^
((y >> 2 & 1) * xtime(xtime(x))) ^
((y >> 3 & 1) * xtime(xtime(xtime(x)))) ^
((y >> 4 & 1) * xtime(xtime(xtime(xtime(x))))));
}
#else
#define Multiply(x, y) \
( ((y & 1) * x) ^ \
((y>>1 & 1) * xtime(x)) ^ \
((y>>2 & 1) * xtime(xtime(x))) ^ \
((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ \
((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))) \
#endif
// MixColumns function mixes the columns of the state matrix.
// The method used to multiply may be difficult to understand for the inexperienced.
// Please use the references to gain more information.
static void InvMixColumns(void)
{
int i;
unsigned char a, b, c, d;
for (i = 0; i < 4; ++i)
{
a = (*state)[i][0];
b = (*state)[i][1];
c = (*state)[i][2];
d = (*state)[i][3];
(*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
(*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
(*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
(*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
}
}
// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
static void InvSubBytes(void)
{
unsigned char i, j;
for (i = 0; i < 4; ++i)
{
for (j = 0; j < 4; ++j)
{
(*state)[j][i] = getSBoxInvert((*state)[j][i]);
}
}
}
static void InvShiftRows(void)
{
unsigned char temp;
// Rotate first row 1 columns to right
temp = (*state)[3][1];
(*state)[3][1] = (*state)[2][1];
(*state)[2][1] = (*state)[1][1];
(*state)[1][1] = (*state)[0][1];
(*state)[0][1] = temp;
// Rotate second row 2 columns to right
temp = (*state)[0][2];
(*state)[0][2] = (*state)[2][2];
(*state)[2][2] = temp;
temp = (*state)[1][2];
(*state)[1][2] = (*state)[3][2];
(*state)[3][2] = temp;
// Rotate third row 3 columns to right
temp = (*state)[0][3];
(*state)[0][3] = (*state)[1][3];
(*state)[1][3] = (*state)[2][3];
(*state)[2][3] = (*state)[3][3];
(*state)[3][3] = temp;
}
// Cipher is the main function that encrypts the PlainText.
static void Cipher(void)
{
unsigned char round = 0;
// Add the First round key to the state before starting the rounds.
AddRoundKey(0);
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for (round = 1; round < Nr; ++round)
{
SubBytes();
ShiftRows();
MixColumns();
AddRoundKey(round);
}
// The last round is given below.
// The MixColumns function is not here in the last round.
SubBytes();
ShiftRows();
AddRoundKey(Nr);
}
static void InvCipher(void)
{
unsigned char round = 0;
// Add the First round key to the state before starting the rounds.
AddRoundKey(Nr);
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for (round = (Nr - 1); round > 0; --round)
{
InvShiftRows();
InvSubBytes();
AddRoundKey(round);
InvMixColumns();
}
// The last round is given below.
// The MixColumns function is not here in the last round.
InvShiftRows();
InvSubBytes();
AddRoundKey(0);
}
/*****************************************************************************/
/* Public functions: */
/*****************************************************************************/
#if defined(ECB) && (ECB == 1)
void gxaes_ecb_encrypt(const unsigned char* input, const unsigned char* key, unsigned char* output, const size_t length)
{
// Copy input to output, and work in-memory on output
memcpy(output, input, length);
state = (state_t*)output;
Key = key;
KeyExpansion();
// The next function call encrypts the PlainText with the Key using AES algorithm.
Cipher();
}
void gxaes_ecb_decrypt(const unsigned char* input, const unsigned char* key, unsigned char *output, const size_t length)
{
// Copy input to output, and work in-memory on output
memcpy(output, input, length);
state = (state_t*)output;
// The KeyExpansion routine must be called before encryption.
Key = key;
KeyExpansion();
InvCipher();
}
#endif // #if defined(ECB) && (ECB == 1)
#if defined(CBC) && (CBC == 1)
static void XorWithIv(unsigned char* buf)
{
unsigned char i;
for (i = 0; i < BLOCKLEN; ++i) //WAS for(i = 0; i < KEYLEN; ++i) but the block in AES is always 128bit so 16 bytes!
{
buf[i] ^= Iv[i];
}
}
void gxaes_cbc_encrypt(unsigned char* output, unsigned char* input, uint32_t length, const unsigned char* key, const unsigned char* iv)
{
uintptr_t i;
unsigned char extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */
// Skip the key expansion if key is passed as 0
if (0 != key)
{
Key = key;
KeyExpansion();
}
if (iv != 0)
{
Iv = (unsigned char*)iv;
}
for (i = 0; i < length; i += BLOCKLEN)
{
XorWithIv(input);
memcpy(output, input, BLOCKLEN);
state = (state_t*)output;
Cipher();
Iv = output;
input += BLOCKLEN;
output += BLOCKLEN;
//printf("Step %d - %d", i/16, i);
}
if (extra)
{
memcpy(output, input, extra);
state = (state_t*)output;
Cipher();
}
}
void gxaes_cbc_decrypt(unsigned char* output, unsigned char* input, uint32_t length, const unsigned char* key, const unsigned char* iv)
{
uintptr_t i;
unsigned char extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */
// Skip the key expansion if key is passed as 0
if (0 != key)
{
Key = key;
KeyExpansion();
}
// If iv is passed as 0, we continue to encrypt without re-setting the Iv
if (iv != 0)
{
Iv = (unsigned char*)iv;
}
for (i = 0; i < length; i += BLOCKLEN)
{
memcpy(output, input, BLOCKLEN);
state = (state_t*)output;
InvCipher();
XorWithIv(output);
Iv = input;
input += BLOCKLEN;
output += BLOCKLEN;
}
if (extra)
{
memcpy(output, input, extra);
state = (state_t*)output;
InvCipher();
}
}
#endif // #if defined(CBC) && (CBC == 1)
#endif //DLMS_IGNORE_AES
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