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AES_modified.cpp
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#include <iostream>
#include <bitset>
#include <string>
using namespace std;
//AES-128 requires 10 rounds of encryption
const int total_round = 10;
//key_size_in_word Represents the number of word s that are input keys
const int key_size_in_word = 4;
// substitution box
bitset<8> substitution_box[16][16] = {
{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}
};
// inverse substitution box
bitset<8> inverse_substitution_box[16][16] = {
{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}
};
// matrix round constant which is used in key_expansion
bitset<32> Round_constant[10] = {0x02000000, 0x03000000, 0x05000000, 0x06000000, 0x70000000,
0x80000000, 0x90000000, 0x10000000, 0x5b000000, 0x56000000};
// function to convert four_byte to one_word
bitset<32> converter_word(bitset<8>& k1,bitset<8>& k2, bitset<8>& k3, bitset<8>& k4)
{
// taking a variable that store intially zero in hex
bitset<32> ans(0x00000000);
// temporory variable
bitset<32> mal;
// converting bitset to unsigned long
mal = k1.to_ulong();
// left shift by 24
mal <<= 24;
// or with temporory variable
ans |= mal;
// converting bitset to unsigned long
mal = k2.to_ulong();
//left shift by 16
mal <<= 16;
// or with temporory varible
ans |= mal;
// converting bitset to unsigned lon
mal = k3.to_ulong();
//left shift by 8
mal <<= 8;
// or with temporory varible
ans |= mal;
//// converting bitset to unsigned lon
mal = k4.to_ulong();
//or with temporory varible
ans |= mal;
// returning after converting into word
return ans;
}
// function used to to left shift by one
bitset<32> left_shift_by_one(bitset<32>& read_word)
{
//storing the bitset by left shift eight
bitset<32> above = read_word << 8;
// storing the bitset by rightshift by 24
bitset<32> below= read_word >> 24;
// performing or operation and then return the result
return above | below;
}
// transformation by s_box for every byte in word
bitset<32> substitution_fun_word(bitset<32> read_word)
{
// a declaration of temporory bitset type variable
bitset<32> mal;
//iterating over substitution box to susbstitution perform
for(int w=0; w<32; w+=8)
{
// calculation of row for substitution
int row = read_word[w+7]*8 + read_word[w+6]*4 + read_word[w+5]*2 + read_word[w+4];
// calculation of column for substitution
int column = read_word[w+3]*8 + read_word[w+2]*4 + read_word[w+1]*2 + read_word[w];
// performing the substitution
bitset<8> val = substitution_box[row][column];
for(int m=0; m<8; ++m)
mal[w+m] = val[m];
}
// returning the result
return mal;
}
// function used to expand the key
void fun_expansion_key(bitset<8> key[4*key_size_in_word], bitset<32>w[4*(total_round+1)])
{
// a variable declaration of type bitset
bitset<32> mal;
// declaration and initialization of varible
int lol= 0;
// starting four is input key as s
while(lol < key_size_in_word)
{
// calling to converter_word function
w[lol] = converter_word(key[4*lol], key[4*lol+1], key[4*lol+2], key[4*lol+3]);
//increament the varible
++lol;
}
// storing the key size in lol variable
lol= key_size_in_word;
// iteration
while(lol < 4*(total_round+1))
{
//Record the previous word
mal = w[lol-1];
//cheking position is divisible by key size or not
if(lol % key_size_in_word == 0)
{
// if true the abolve condition the store into w[]
w[lol] = w[lol-key_size_in_word] ^ substitution_fun_word(left_shift_by_one(mal)) ^ Round_constant[lol/key_size_in_word-1];
}
else
{
// if above condition is false then store into w[]
w[lol] = w[lol-key_size_in_word] ^ mal;
}
++lol;
}
}
//implementing AES
// definition of substitution byte function
void substitution_byte_function(bitset<8> matrix[4*4])
{
// taking a variable to iterate over susbstitution box
int w=0;
while(w<16)
{
// calculation of row
int row = matrix[w][7]*8 + matrix[w][6]*4 + matrix[w][5]*2 + matrix[w][4];
// calculation of column
int col = matrix[w][3]*8 + matrix[w][2]*4 + matrix[w][1]*2 + matrix[w][0];
//string into matrix according to row and column
matrix[w] = substitution_box[row][col];
//increament
w++;
}
}
// definition of shifting left row function
void shifting_left_row_function(bitset<8> matrix[4*4])
{
// left shift by one of second row
bitset<8> mal = matrix[4];
// performing left shift operation
for(int w=0; w<3; ++w)
matrix[w+4] = matrix[w+5];
matrix[7] = mal;
// move two places of third line of circle
for(int w=0; w<2; ++w)
{
// taking a temp varible and store the element at position w+8
mal = matrix[w+8];
//w+8 position occupied by w+10
matrix[w+8] = matrix[w+10];
// w+10 position is filled by temp variable for shifting operation
matrix[w+10] = mal;
}
// move three places of third line of circle
mal = matrix[15];
for(int u=3; u>0; --u)
// storing u+11 element to u+12
matrix[u+12] = matrix[u+11];
//stroing temporory varible to at position 12
matrix[12] = mal;
}
// multiplication on finite field
bitset<8> multiplication_by_gf(bitset<8> mal1, bitset<8> mal2) {
// declaration of varible of type bitset
bitset<8> pppp = 0;
// again declaration of temprory variable of type bitset
bitset<8> set_bit;
//performing the multiplication operation
for (int counter = 0; counter < 8; counter++) {
// checking condition
if ((mal2 & bitset<8>(1)) != 0) {
// xor operation
pppp ^= mal1;
}
set_bit = (bitset<8>) (mal1 & bitset<8>(0x80));
//left shift by one
mal1 <<= 1;
// checking condition
if (set_bit != 0) {
//performing x-or operation
/* y^8 + y^4 + y^3 + y + 1 */
mal1 ^= 0x1b;
}
//right shift by one
mal2 >>= 1;
}
// returning the result
return pppp;
}
// definition of mix_column function to perform mix_column operation
void mix_column_function(bitset<8> matrix[4*4])
{
// declaration of array of size 4 of type bitset
bitset<8> array[4];
//iteration
for(int a=0; a<4; ++a)
{
// internal iteration
for(int b=0; b<4; ++b)
// storing into array temp
array[b] = matrix[a+b*4];
// performing the relavant operation to perform mix_coumn function
matrix[a] = multiplication_by_gf(0x02, array[0]) ^ multiplication_by_gf(0x03, array[1]) ^ array[2] ^ array[3];
// stroing at a+4 position
matrix[a+4] = array[0] ^ multiplication_by_gf(0x02, array[1]) ^ multiplication_by_gf(0x03, array[2]) ^ array[3];
// stroing at a+8 position
matrix[a+8] = array[0] ^ array[1] ^ multiplication_by_gf(0x02, array[2]) ^ multiplication_by_gf(0x03, array[3]);
// storing at a+12 position
matrix[a+12] = multiplication_by_gf(0x03, array[0]) ^ array[1] ^ array[2] ^ multiplication_by_gf(0x02, array[3]);
}
}
// definition of adding key function
void adding_round_key_function(bitset<8> matrix[4*4], bitset<32>kate[4])
{
// iteration
for(int a=0; a<4; ++a)
{
// perform the right shift then store in kate1
bitset<32> kate1 = kate[a] >> 24;
//perform the left shift followed by right shift then store in kate2
bitset<32> kate2 = (kate[a] << 8) >> 24;
//perform the left shift followed by right shift then store in kate3
bitset<32> kate3 = (kate[a] << 16) >> 24;
//perform the left shift followed by right shift then store in kate3
bitset<32> kate4 = (kate[a] << 24) >> 24;
// performing the x-or then store at position a
matrix[a] = matrix[a] ^ bitset<8>(kate1.to_ulong());
// performing the x-or then store at position a+4
matrix[a+4] = matrix[a+4] ^ bitset<8>(kate2.to_ulong());
// performing the x-or then store at position a+8
matrix[a+8] = matrix[a+8] ^ bitset<8>(kate3.to_ulong());
// performing the x-or then store at position a+12
matrix[a+12] = matrix[a+12] ^ bitset<8>(kate4.to_ulong());
}
}
// definition of inverse substitution function
void inverse_substitution_function(bitset<8> matrix[4*4])
{
// iteration
for(int a=0; a<16; ++a)
{ // calculation of row
int row = matrix[a][7]*8 + matrix[a][6]*4 + matrix[a][5]*2 + matrix[a][4];
//calculation of column
int column = matrix[a][3]*8 + matrix[a][2]*4 + matrix[a][1]*2 + matrix[a][0];
// storing into matrix after calculation of row and column
matrix[a] = inverse_substitution_box[row][column];
}
}
// definition of inverse_shift row function
void inverse_shift_row_function(bitset<8> matrix[4*4])
{
//The second line circle moves one bit to the right
bitset<8> mal = matrix[7];
// iteration
for(int a=3; a>0; --a)
{
// element at position a=3 is store at a+4
matrix[a+4] = matrix[a+3];
}
matrix[4] = mal;
//The third line circle moves two to the right
//iteration
for(int a=0; a<2; ++a)
{
// storing element of position a+8
mal = matrix[a+8];
// storing a+10 element to a+8
matrix[a+8] = matrix[a+10];
// storing back to a+10 from temporory variable
matrix[a+10] = mal;
}
//Fourth line circle moves three to the right
mal = matrix[12];
// iteration
for(int a=0; a<3; ++a)
// stroring element at a+13 to a+12
matrix[a+12] = matrix[a+13];
// storing at last frm temprory varible
matrix[15] = mal;
}
// definition of mix_column while decryption
void mix_column_inverse(bitset<8> matrix[4*4])
{
// a temporory variable of type bitset
bitset<8> arr[4];
// iteration
for(int a=0; a<4; ++a)
{
// internal iteration
for(int b=0; b<4; ++b)
// mix column_operation
arr[b] =matrix[a+b*4];
// storing at position a
matrix[a] = multiplication_by_gf(0x0e, arr[0]) ^ multiplication_by_gf(0x0b, arr[1]) ^ multiplication_by_gf(0x0d, arr[2]) ^ multiplication_by_gf(0x09, arr[3]);
// storing at position a+4
matrix[a+4] = multiplication_by_gf(0x09, arr[0]) ^ multiplication_by_gf(0x0e, arr[1]) ^ multiplication_by_gf(0x0b, arr[2]) ^ multiplication_by_gf(0x0d, arr[3]);
// storing at position a+8
matrix[a+8] = multiplication_by_gf(0x0d, arr[0]) ^ multiplication_by_gf(0x09, arr[1]) ^ multiplication_by_gf(0x0e, arr[2]) ^ multiplication_by_gf(0x0b, arr[3]);
// storing at position a+12
matrix[a+12] = multiplication_by_gf(0x0b, arr[0]) ^ multiplication_by_gf(0x0d, arr[1]) ^ multiplication_by_gf(0x09, arr[2]) ^ multiplication_by_gf(0x0e, arr[3]);
}
}
// definition of encryption function
void encryption_function(bitset<8> inct[4*4], bitset<32> toy[4*(total_round+1)])
{
// temporory array of type bitset
bitset<32> key[4];
//iterartion
for(int i=0; i<4; ++i)
{
// stroing the element of toy to temporory array
key[i] = toy[i];
}
// calling to adding key function
adding_round_key_function(inct, key);
// iteration
for(int round=1; round<total_round; ++round)
{
//calling to substitution byte function
substitution_byte_function(inct);
//calling to leftshift function
shifting_left_row_function(inct);
//calling to mix_column function
mix_column_function(inct);
// iteration
for(int i=0; i<4; ++i)
//performing operation
key[i] = toy[4*round+i];
// calling to adding key round function
adding_round_key_function(inct, key);
}
// calling to substitution byte function
substitution_byte_function(inct);
// calling to shifting_left_row_function
shifting_left_row_function(inct);
// looping
for(int i=0; i<4; ++i)
{
// operation
key[i] = toy[4*total_round+i];
}
// calling to adding round key function
adding_round_key_function(inct, key);
}
// function of decryption function
void decryption_function_AES(bitset<8> inct[4*4], bitset<32> toy[4*(total_round+1)])
{
// temporory variable
bitset<32> key[4];
// iteration
for(int a=0; a<4; ++a)
{
// performing relevant operation
key[a] = toy[4*total_round+a];
}
// calling to adding round key function
adding_round_key_function(inct, key);
// performing the total round in iverse order
for(int round=total_round-1; round>0; --round)
{
// calling to inverse shift row function
inverse_shift_row_function(inct);
// calling to inverse_substitution_function
inverse_substitution_function(inct);
// iteration
for(int a=0; a<4; ++a)
{
// storing into key
key[a] = toy[4*round+a];
}
// calling to adding_round_key_function
adding_round_key_function(inct, key);
// calling to mix_column_inverse
mix_column_inverse(inct);
}
// calling to inverse_shift_row_function
inverse_shift_row_function(inct);
// calling to inverse_substitution_function
inverse_substitution_function(inct);
// iteration
for(int a=0; a<4; ++a)
{
// stroring into key array
key[a] = toy[a];
}
// calling to adding_round_key_function
adding_round_key_function(inct, key);
}
// main function
int main()
{
// plane_text
bitset<8> plain[16] = {0x31, 0x87, 0x66, 0x76,
0x42, 0x54, 0x81, 0x97,
0x02, 0x10, 0x95, 0x17,
0xb8, 0xfd, 0xd2, 0xa4};
// key
bitset<8> key[16] = {0x22, 0x73, 0x95, 0x86,
0x25, 0xfe, 0xf2, 0xa6,
0x4b, 0x77, 0xa5, 0xe8,
0x19, 0x3f, 0x45, 0x37};
// temporory container of type bitset
bitset<32> w[4*(total_round+1)];
// calling to fun_expansion_key
fun_expansion_key(key, w);
// printing plane_text
cout<<"Plane_Text"<<endl;
// a variable
int a=0;
// printing plane text
while(a<16)
{
// printing containt after converting into unsigned long
cout << hex << plain[a].to_ulong() << " ";
// if position is divisible by 4
if((a+1)%4 == 0)
{
// printing newline
cout << endl;
}
//increament
a++;
}
//printing new line
cout<<endl;
//Encryption, output ciphertext
encryption_function(plain, w);
// print a text as cipherText
cout << "ciphertext:"<<endl;
//variable
a=0;
// printing cipher_text
while(a<16)
{
// print element of cipher_text after converting into unsigned long
cout << hex << plain[a].to_ulong() << " ";
//if (a+1) is divisible by four
if((a+1)%4 == 0)
{
// printing new line
cout << endl;
}
// increament
a++;
}
// printing new_line
cout << endl;
//Decrypt, output plaintext
decryption_function_AES(plain, w);
// printing a text as Decrypted plaintext:
cout << "Decrypted plaintext:"<<endl;
// variable
a=0;
// printing decrypted message
while(a<16)
{
// printing eleent of decrypted message
cout << hex << plain[a].to_ulong() << " ";
// checking condition(a+1) is divisible by four or not
if((a+1)%4 == 0)
{
// if divisible by four then printing new line
cout << endl;
}
// incrementation
a++;
}
// printing new line
cout << endl;
// returning zero from main function
return 0;
}