/*
******************************************************************
**       Advanced Encryption Standard implementation in C.      **
******************************************************************
This is the source code for encryption using the latest AES algorithm.
******************************************************************
*/

// Include stdio.h for standard input/output.
// Used for giving output to the screen.
#include<stdio.h>
#include “stdafx.h”

// The number of columns comprising a state in AES. This is a constant in AES. Value=4
#define Number_of_columns  4
#define LENGTH_OF_BLOCK 16
#define MAX_SIZE_OF_BUCKET 1000
#define VALUE_FOR_INSERT  “VALUE_FOR_INSERT”
#define NUMBER_OF_KEYS 700

// The number of rounds in AES Cipher. It is simply initiated to zero. The actual value is recieved in the program.
const int Number_of_Round = 10;

// The number of 32 bit words in the key. It is simply initiated to zero. The actual value is recieved in the program.
const int Nk = 4;

// in – it is the array that holds the plain text to be encrypted.
// out – it is the array that holds the output CipherText after encryption.
// state – the array that holds the intermediate results during encryption.
unsigned char in[16], out[16], state[4][4];
char *bucket[MAX_SIZE_OF_BUCKET] = {NULL};
int Nbr_of_colision = 0;

// The array that stores the round keys.
unsigned char RoundKey[240];

// The Key input to the AES Program
unsigned char Key[32];

// 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(28)
// Note that i starts at 1, not 0).
int Rcon[255] = {
  0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
  0x2f, 0x5e, 0xbc, 0x63, 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, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
  0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 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, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
  0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 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, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
  0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 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, 0x01, 0x02, 0x04,
  0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
  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
};

/* S_Box */
int getSBoxValue(int num)
{
  int 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, //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
  };

  return sbox[num];
}

// This function produces Number_of_columns(Number_of_Round+1) round keys. The round keys are used in each round to encrypt the states.
/* Simply this function create keys that used each round */
void KeyExpansion()
{
  int i,j;
  unsigned char temp[4],k;

  // The first round key is the key itself.
  for(i=0;i<Nk;i++)
  {
    RoundKey[i*4]=Key[i*4];
    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.
  while (i < (Number_of_columns * (Number_of_Round+1)))
  {
    for(j=0;j<4;j++)
    {
      temp[j]=RoundKey[(i-1) * 4 + j];
    }
    if (i % Nk == 0)
    {
      // This function rotates the 4 bytes in a word to the left once.
      // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]

      // Function RotWord()
      {
        k = temp[0];
        temp[0] = temp[1];
        temp[1] = temp[2];
        temp[2] = temp[3];
        temp[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()
      {
        temp[0]=getSBoxValue(temp[0]);
        temp[1]=getSBoxValue(temp[1]);
        temp[2]=getSBoxValue(temp[2]);
        temp[3]=getSBoxValue(temp[3]);
      }

      temp[0] =  temp[0] ^ Rcon[i/Nk];
    }
    else if (Nk > 6 && i % Nk == 4)
    {
      // Function Subword()
      {
        temp[0]=getSBoxValue(temp[0]);
        temp[1]=getSBoxValue(temp[1]);
        temp[2]=getSBoxValue(temp[2]);
        temp[3]=getSBoxValue(temp[3]);
      }
    }
    RoundKey[i*4+0] = RoundKey[(i-Nk)*4+0] ^ temp[0];
    RoundKey[i*4+1] = RoundKey[(i-Nk)*4+1] ^ temp[1];
    RoundKey[i*4+2] = RoundKey[(i-Nk)*4+2] ^ temp[2];
    RoundKey[i*4+3] = RoundKey[(i-Nk)*4+3] ^ temp[3];
    i++;
  }
}

// This function adds the round key to state.
// The round key is added to the state by an XOR function.
void AddRoundKey(int round)
{
  int i,j;
  for(i=0;i<4;i++)
  {
    for(j=0;j<4;j++)
    {
      state[j][i] ^= RoundKey[round * Number_of_columns * 4 + i * Number_of_columns + j];
    }
  }
}

// The SubBytes Function Substitutes the values in the  
// state matrix with values in an S-box.  
void SubBytes()  
{  
  int i,j;  
  for(i=0;i<4;i++)  
  {  
    for(j=0;j<4;j++)  
    {  
      state[i][j] = getSBoxValue(state[i][j]);
    }  
  }  
}  

// 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.
void ShiftRows()
{
  unsigned char temp;

  // Rotate first row 1 columns to left
  temp=state[1][0];
  state[1][0]=state[1][1];
  state[1][1]=state[1][2];
  state[1][2]=state[1][3];
  state[1][3]=temp;

  // Rotate second row 2 columns to left
  temp=state[2][0];
  state[2][0]=state[2][2];
  state[2][2]=temp;

  temp=state[2][1];
  state[2][1]=state[2][3];
  state[2][3]=temp;

  // Rotate third row 3 columns to left
  temp=state[3][0];
  state[3][0]=state[3][3];
  state[3][3]=state[3][2];
  state[3][2]=state[3][1];
  state[3][1]=temp;
}  

// xtime is a macro that finds the product of {02} and the argument to xtime modulo {1b}    
#define xtime(x)   ((x<<1) ^ (((x>>7) & 1) * 0x1b))

// MixColumns function mixes the columns of the state matrix  
// The method used may look complicated, but it is easy if you know the underlying theory.  
// Refer the documents specified above.  
void MixColumns()
{
  int i;
  unsigned char Tmp,Tm,t;
  for(i=0;i<4;i++)
  {
    t=state[0][i];
    Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ;
    Tm = state[0][i] ^ state[1][i] ; Tm = xtime(Tm); state[0][i] ^= Tm ^ Tmp ;
    Tm = state[1][i] ^ state[2][i] ; Tm = xtime(Tm); state[1][i] ^= Tm ^ Tmp ;
    Tm = state[2][i] ^ state[3][i] ; Tm = xtime(Tm); state[2][i] ^= Tm ^ Tmp ;
    Tm = state[3][i] ^ t ; Tm = xtime(Tm); state[3][i] ^= Tm ^ Tmp ;
  }
}

// Cipher is the main function that encrypts the PlainText.
void Cipher()
{
  int i,j,round=0;

  //Copy the input PlainText to state array.
  for(i=0;i<4;i++)
  {
    for(j=0;j<4;j++)
    {
      state[j][i] = in[i*4 + j];
    }
  }

  // Add the First round key to the state before starting the rounds.  
  AddRoundKey(0);   

  // There will be Number_of_Round rounds.  
  // The first Number_of_Round-1 rounds are identical.  
  // These Number_of_Round-1 rounds are executed in the loop below.  
  for (round = 1; round < Number_of_Round; 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 (Number_of_Round);

  // The encryption process is over.
  // Copy the state array to output array.
  for (i = 0; i < 4; i++)
  {
    for(j = 0; j < 4; j++)
    {
      out[i*4+j] = state[j][i];
    }
  }
}

int
Hash_Function(unsigned char Key[LENGTH_OF_BLOCK])
{
  int idx = 0;
  int i;

  for (i=0; i<LENGTH_OF_BLOCK; i++) {
    idx = idx + (Key[i] * Key[i]);
  }

  idx = idx % MAX_SIZE_OF_BUCKET;

  return idx;
}

void
insert_value_to_table (int idx)
{
  /* Collision is not occur!! */
  if (bucket[idx] == NULL) {
    bucket[idx] = VALUE_FOR_INSERT;
  }

  /* Collision occur */
  else {
    /* Solution : Open Address */
    while (bucket[idx] != NULL){
      Nbr_of_colision++;
      idx++;
    }

    bucket[idx] = VALUE_FOR_INSERT;
  }
}

int _tmain (int argc, _TCHAR* argv[])
{
  int i, idx, cnt, breath;

  // The array temp stores the key.
  // The array temp2 stores the plaintext.
  unsigned char temp_key[16] = {0x00  ,0x01  ,0x02  ,0x03  ,0x04  ,0x05  ,0x06  ,0x07  ,0x08  ,0x09  ,0x0a  ,0x0b  ,0x0c  ,0x0d  ,0x0e  ,0x0f};
  unsigned char temp_text[16] = {0x00  ,0x11  ,0x22  ,0x33  ,0x44  ,0x55  ,0x66  ,0x77  ,0x88  ,0x99  ,0xaa  ,0xbb  ,0xcc  ,0xdd  ,0xee  ,0xff};

  for (cnt=0; cnt<NUMBER_OF_KEYS; cnt++) {
    if (cnt < 100)
      temp_text[0]++;
    else if (cnt < 200)
      temp_text[1]++;
    else if (cnt < 300)
      temp_text[2]++;
    else if (cnt < 400)
      temp_text[3]++;
    else if (cnt < 500)
      temp_text[4]++;
    else if (cnt < 600)
      temp_text[5]++;
    else if (cnt < NUMBER_OF_KEYS)
      temp_text[6]++;

    // Copy the Key and PlainText
    for(i=0; i<Nk*4; i++)
    {
      Key[i] = temp_key[i];
      in[i] = temp_text[i];
    }

    // The KeyExpansion routine must be called before encryption.
    /* Key Expansion create keys used each step */
    KeyExpansion ();

    // The next function call encrypts the PlainText with the Key using AES algorithm.
    Cipher ();

    idx = Hash_Function (out);
 
    insert_value_to_table (idx);
  }

  printf(“NUMBER OF COLISION : %d”, Nbr_of_colision);
  scanf(“%d”, &breath);
}

학교 수업시간에 배운 AES 알고리즘으로 Hash Key를 생성하고

Hash Key를 index로 사용해서 value를 저장하는 소스!!

Load Factor(number of key / size of hash table)가 70%일때 어느 정도의 collision이 발생하는지를

테스트하기 위한 소스코드.