encryptionkeys.h

/******************************************************************************
* Copyright 2015-2020 Xilinx, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/

#pragma once

#ifndef _ENCRYPTIONKEYS_H_
#define _ENCRYPTIONKEYS_H_

#include "stdio.h"
#include "stdint.h"
#include "string.h"
#include <cmath>
#include <iostream>

uint8_t Separator = 0x00;

static const uint8_t sbox[256] = {
    //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,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    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 };

static const uint8_t rsbox[256] = {
    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 };

static const uint8_t Rcon[11] = {
    0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };

uint8_t expanded_key[240];

uint8_t cmac_key[32];
uint8_t K1[16];
uint8_t K2[16];

/******************************************************************************/
void copy_array_uint64_t(uint64_t *dst, uint64_t *src, int length) 
{
    int index;
    for (index = 0; index<length; index++) 
    {
        dst[index] = src[index];
    }
}

/******************************************************************************/
void copy_array_uint8_t(uint8_t *dst, uint8_t *src, int size) 
{
    int index;

    for (index = 0; index<size; index++) 
    {
        dst[index] = src[index];
    }
}

/******************************************************************************/
void copy_uint8_t_uint64_t(uint64_t *dst, uint8_t *src, int size) 
{
    int index8;
    int index64;

    index64 = 0;
    for (index8 = 0; index8<size; index8++) 
    {
        if (index8 % 8 == 0) 
        {
            dst[index64] = 0;
        }
        dst[index64] = (dst[index64] << 8) | src[index8];
        if (index8 % 8 == 7) 
        {
            index64++;
        }
    }
}

/******************************************************************************/
void xor_array_uint64_t(uint64_t *dst, uint64_t *src, int size) 
{
    int index;

    /* Xor the source onto the destination */
    for (index = 0; index<size; index++) 
    {
        dst[index] ^= src[index];
    }
}

/******************************************************************************/
void xor_array_uint8_t(uint8_t *dst, uint8_t *src, int size) 
{
    int index;

    /* Xor the source onto the destination */
    for (index = 0; index<size; index++) 
    {
        dst[index] ^= src[index];
    }
}

/******************************************************************************/
void add_array_uint64_t(uint64_t *dst, uint64_t *src, int length) 
{
    int index;

    for (index = 0; index<length; index++) 
    {
        dst[index] += src[index];
    }
}

/******************************************************************************/
void str_2_uint8_t(uint8_t *dst, char *str, int char_count) 
{
    int char_index;
    int byte_index;
    uint8_t nibble;

    byte_index = 0;
    for (char_index = 0; char_index<char_count; char_index++) 
    {
        /* Initialize the byte */
        if (char_index % 2 == 0) 
        {
            dst[byte_index] = 0;
        }

        /* Calculate the nibble */
        if ((str[char_index] >= '0') && (str[char_index] <= '9')) 
        {
            nibble = (str[char_index] - '0');
        }
        else if ((str[char_index] >= 'a') && (str[char_index] <= 'f')) 
        {
            nibble = (str[char_index] - 'a' + 10);
        }
        else if ((str[char_index] >= 'A') && (str[char_index] <= 'F')) 
        {
            nibble = (str[char_index] - 'F' + 10);
        }
        else 
        {
            nibble = 0;
        }

        /* Shift in the nibble */
        dst[byte_index] = (dst[byte_index] << 4) | nibble;

        /* Increment the byte pointer as needed */
        if (char_index % 2 == 1) 
        {
            byte_index++;
        }
    }
}

/******************************************************************************/
void uint64_t_2_str(char *str, uint64_t *src, int word_count) 
{
    int word_index;
    int nibble_count;
    int  mychar;

    for (word_index = 0; word_index<word_count; word_index++) 
    {
        for (nibble_count = 0; nibble_count<16; nibble_count++) 
        {
            mychar = (int)(src[word_index] >> (60 - 4 * (nibble_count))) & 0xF;
#ifdef __GNUC__
            sprintf(&str[16 * word_index + nibble_count], "%x", mychar);
#else
            sprintf_s(&str[16 * word_index + nibble_count], 64, "%x", mychar);
#endif
        }
    }
}

/******************************************************************************/
static void rotate_word(uint8_t *t, int size, int stride, int offset) 
{
    uint8_t temp;
    int index;
    int shift_count;

    /* Count how many shifts happen */
    for (shift_count = 0; shift_count<offset; shift_count++) 
    {
        /* Rotate the word */
        temp = t[0];
        for (index = 1; index<size; index++) 
        {
            t[stride*(index - 1)] = t[stride*index];
        }
        t[stride*(size - 1)] = temp;
    }
}

/******************************************************************************/
static void sbox_word(uint8_t *t, int size) 
{
    int index;

    /* Apply sbox to all the bytes */
    for (index = 0; index<size; index++) 
    {
        t[index] = sbox[t[index]];
    }
}

/******************************************************************************/
static void expand_key(uint8_t *k) 
{
    int word_index, byte_index, iteration;

    /* Copy the 1st 8 words */
    for (word_index = 0; word_index<8; word_index++) 
    {
        for (byte_index = 0; byte_index<4; byte_index++) 
        {
            expanded_key[4 * word_index + byte_index] = k[4 * word_index + byte_index];
        }
    }

    /* Expand the rest of the key */
    iteration = 1;
    for (; word_index<60; word_index++) 
    {
        /* Assign the previous four bytes to the next 4 bytes */
        copy_array_uint8_t(&expanded_key[4 * word_index], &expanded_key[4 * (word_index - 1)], 4);

        /* For the 1st word of this 8 word portion of the expanded key */
        if (word_index % 8 == 0) 
        {
            rotate_word(&expanded_key[4 * word_index], 4, 1, 1);
        }

        /* For the 1st word and 4th word of this 8 word portion do substition */
        if ((word_index % 8 == 0) || (word_index % 8 == 4)) 
        {
            sbox_word(&expanded_key[4 * word_index], 4);
        }

        /* For the 1st word of this 8 word portion of the expanded key */
        if (word_index % 8 == 0) 
        {
            expanded_key[4 * word_index] ^= Rcon[iteration];
            iteration++;
        }

        /* Xor these expanded key bytes with earlier portions */
        xor_array_uint8_t(&expanded_key[4 * word_index], &expanded_key[4 * (word_index - 8)], 4);
    }
}

/******************************************************************************/
static void add_round_key(uint8_t *state, int rnd) 
{
    xor_array_uint8_t(state, &expanded_key[16 * rnd], 16);
}

/******************************************************************************/
static void sub_bytes(uint8_t *state) 
{
    sbox_word(state, 16);
}

/******************************************************************************/
static void shift_rows(uint8_t *state) 
{
    rotate_word(&state[1], 4, 4, 1);
    rotate_word(&state[2], 4, 4, 2);
    rotate_word(&state[3], 4, 4, 3);
}

/******************************************************************************/
static void mix_column(uint8_t *state) 
{
    uint8_t a[4];
    uint8_t b[4];
    uint8_t index;
    uint8_t h;

    /* The array 'a' is simply a copy of the input array 'r'
    * The array 'b' is each element of the array 'a' multiplied by 2
    * in Rijndael's Galois field
    * a[n] ^ b[n] is element n multiplied by 3 in Rijndael's Galois field */
    for (index = 0; index<4; index++) 
    {
        a[index] = state[index];
        h = (0x80 & state[index]) ? 0xff : 0x00;
        b[index] = state[index] << 1;
        b[index] ^= 0x1b & h;
    }
    state[0] = b[0] ^ a[3] ^ a[2] ^ b[1] ^ a[1]; /* 2 * a0 + a3 + a2 + 3 * a1 */
    state[1] = b[1] ^ a[0] ^ a[3] ^ b[2] ^ a[2]; /* 2 * a1 + a0 + a3 + 3 * a2 */
    state[2] = b[2] ^ a[1] ^ a[0] ^ b[3] ^ a[3]; /* 2 * a2 + a1 + a0 + 3 * a3 */
    state[3] = b[3] ^ a[2] ^ a[1] ^ b[0] ^ a[0]; /* 2 * a3 + a2 + a1 + 3 * a0 */
}

/******************************************************************************/
static void mix_columns(uint8_t *state) 
{
    int column;

    for (column = 0; column<4; column++) 
    {
        mix_column(&state[4 * column]);
    }
}

/******************************************************************************/
static void block_cipher(uint8_t *pt, uint8_t *ct) 
{
    int rnd;

    copy_array_uint8_t(ct, pt, 16);
    add_round_key(ct, 0);
    for (rnd = 1; rnd<14; rnd++) 
    {
        sub_bytes(ct);
        shift_rows(ct);
        mix_columns(ct);
        add_round_key(ct, rnd);
    }
    sub_bytes(ct);
    shift_rows(ct);
    add_round_key(ct, rnd);
}

/******************************************************************************/
void ecb_encrypt(uint8_t *key, uint8_t *pt, uint8_t *ct, int blocks) 
{
    int block_count;

    expand_key(key);

    for (block_count = 0; block_count<blocks; block_count++) 
    {
        block_cipher(&pt[16 * block_count], &ct[16 * block_count]);
    }
}

/******************************************************************************/
void cbc_encrypt(uint8_t *iv, uint8_t *key, uint8_t *pt, uint8_t *ct, int blocks) 
{
    int block_count;
    uint8_t cipher_input[16];

    expand_key(key);
    copy_array_uint8_t(cipher_input, iv, 16);

    for (block_count = 0; block_count<blocks; block_count++) 
    {
        xor_array_uint8_t(cipher_input, &pt[16 * block_count], 16);
        block_cipher(cipher_input, &ct[16 * block_count]);
        copy_array_uint8_t(cipher_input, &ct[16 * block_count], 16);
    }
}

/******************************************************************************/
void gen_cmac_subkeys(uint8_t *key) 
{
    uint8_t pt[16] = { 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0 };
    uint8_t Rb[16] = { 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0x87 };
    uint8_t L[16];
    int i;

    /* NIST SP 800-38B 6.1 Step 1 */
    copy_array_uint8_t(cmac_key, key, 32);
    ecb_encrypt(cmac_key, pt, L, 1);

    /* NIST SP 800-38B 6.1 Step 2 */
    for (i = 0; i<15; i = i + 1) 
    {
        K1[i] = (L[i] << 1) | (L[i + 1] >> 7);
    }
    K1[15] = L[i] << 1;
    if ((L[0] & 0x80) != 0)
    {
        for (i = 0; i<16; i = i + 1) 
        {
            K1[i] ^= Rb[i];
        }
    }

    /* NIST SP 800-38B 6.1 Step 3 */
    for (i = 0; i<15; i = i + 1)
    {
        K2[i] = (K1[i] << 1) | (K1[i + 1] >> 7);
    }
    K2[15] = K1[i] << 1;
    if ((K1[0] & 0x80) != 0)
    {
        for (i = 0; i<16; i = i + 1) 
        {
            K2[i] ^= Rb[i];
        }
    }
}

/******************************************************************************/
void cmac(uint8_t *mac, uint8_t *msg, int total_bytes) 
{
    int block;
    uint8_t ct[16];
    uint8_t pt[16];
    
    int lastBlockSize = total_bytes - ((total_bytes/16) *16);
    int total_blocks = (total_bytes / 16) + ((total_bytes % 16) == 0 ? 0 : 1);

    for (block = 0; block < total_blocks; block++) 
    {
        copy_array_uint8_t(pt, &msg[16 * block], 16);
        if (block == total_blocks - 1) 
        {
            if (lastBlockSize == 0)
            {
                xor_array_uint8_t(pt, K1, 16);
            }
            else 
            {
                pt[lastBlockSize++] = 0x80;
                while(lastBlockSize & 15)
                    pt[lastBlockSize++] = 0x00;
                xor_array_uint8_t(pt, K2, 16);
            }
        }
        if (block != 0) 
        {
            xor_array_uint8_t(pt, ct, 16);
        }
        ecb_encrypt(cmac_key, pt, ct, 1);
    }
    copy_array_uint8_t(mac, ct, 16);
}

#endif