C - Programming Guide

C/C++ Program for Implementation MD5 Hashing Technique

#include<iostream.h>
#include<conio.h>
#include<math.h>

int input[2000],pointer;
int carry;

class Block
{
  public:
  int word[32];
   Block()
  {
   word[32]=0;
  }
   Block operator +(Block);
   void operator =(Block);
   Block operator &(Block);
   Block operator |(Block);
   Block operator ^(Block);
   Block operator !();
   void operator <<(int shift_bits);
}X[16],T[64],a,b,c,d,result,temp;

Block Block::operator +(Block t)
{
   int x,y,ans;
 for(int i=31;i>=0;i--)
 {
  x=word[i];
 y=t.word[i];
 switch(carry)
 {
 case 0: if(((x==0)&&(y==0))||((x==1)&&(y==1)))
  {
  ans=0;
  carry=x;
  }
  if(((x==0)&&(y==1))||((x==1)&&(y==0)))
  {
  ans=1;
  carry=0;
  }
  break;
      



 case 1: if(((x==0)&&(y==0))||((x==1)&&(y==1)))
  {
  ans=1;
  carry=x;
  }
  if(((x==0)&&(y==1))||((x==1)&&(y==0)))
  {
  ans=0;
  carry=1;
  }
  break;
  }
  result.word[i]=ans;
  }
   return(result);
}

Block Block::operator &(Block t)
{
for(int i=0;i<32;i++)
 result.word[i]=word[i] & t.word[i];
return(result);
}

Block Block::operator |(Block t)
{
for(int i=0;i<32;i++)
 result.word[i]=word[i] | t.word[i];
return(result);
}

Block Block::operator ^(Block t)
{
for(int i=0;i<32;i++)
 result.word[i]=word[i] ^ t.word[i];
return(result);
}

Block Block::operator !()
{
for(int i=0;i<32;i++)
 result.word[i]=!word[i];
return(result);
}

void Block::operator=(Block t)
{
for(int i=0;i<32;i++)
 word[i]=t.word[i];
}




//Circular left shift

int get_shift_bits(int round,int step)
{
int bits;
int p[17]={0,7,12,17,22,7,12,17,22,7,12,17,22,7,12,17,22};
int q[17]={0,5,9,14,20,5,9,14,20,5,9,14,20,5,9,14,20};
int r[17]={0,4,11,16,23,4,11,16,23,4,11,16,23,4,11,16,23};
int s[17]={0,6,10,15,21,6,10,15,21,6,10,15,21,6,10,15,21};
switch(round)
{
case 1: bits=p[step];
 break;
case 2: bits=q[step];
 break;
case 3: bits=r[step];
 break;
case 4: bits=s[step];
 break;
}
 return(bits);
}

void Block::operator <<(int shift_bits)
{
 int i,p,j=0;
 p=32-shift_bits;
 for(i=shift_bits;i<p;i++)
   {
     temp.word[j]=word[i];
     j++;
   }
    for(i=0;i<shift_bits;i++)
   {
     temp.word[j]=result.word[i];
     j++;
   }
}
void convert(char msg[])
{
   int charvalue,i,j;
   for(i=0;msg[i]!='\0';i++)
   {
 int temp[8]={0};
 charvalue=(int)msg[i];
 j=0;
 while(charvalue!=0)
 {
   temp[j]=charvalue%2;
   charvalue=charvalue/2;
   j++;
 }
 


 for(j=7;j>=0;j--)
   {
  input[pointer]=temp[j];
  pointer++;
   }
    }
 cout<<"\n length of orignal msg before padding:  " <<pointer;
}
void padding()
{
 int r,p,i,padding_bits;
 r=pointer+64;
 i=1;
 p=512*i;
 while(r>=p)
 {
  i++;
  p=512*i;
 }
 padding_bits=p-r;
 cout<<"\n\npadding bits:"<<padding_bits;
 input[pointer]=1;
 pointer++;
 for(i=1;i<padding_bits;i++)
 {
  input[pointer]=0;
  pointer++;
 }
 cout<<"\n\nlength of message after padding:  "<<pointer;
}
void append_length()
{
 int i,t;
 i=pointer+64;
 t=pointer;
 pointer=i;
 while(t!=0)
 {
  input[i]=t%2;
  t=t/2;
  i--;
   }
   cout<<"\n \n message after padding:\n";
   for(i=0;i<pointer;i++)
  cout<<" "<<input[i];
}
void display(Block t)
{
 cout<<"\n";
 for(int i=0;i<32;i++)
  cout<<t.word[i]<<" ";
}


void div_into_sblk(int round)
{
 int ptr=0,i,j,counter=0,x;
 cout<<"\n\n";
 for(i=0;i<16;i++)
 {
 switch(round)
 {
 case 1:
  ptr=0+ptr;
  break;
 case 2:
  x=1+(5*i);
  ptr=x%16;
  break;
 case 3:
  x=5+(3*i);
  ptr=x%16;
  break;

 case 4:
  x=7*i;
  ptr=x%16;
  break;
 }
 cout<<"\nsubblock"<<i+1<<" :";
 for(j=0;j<32;j++)
 {
  X[ptr].word[j]=input[counter];
  cout<<X[i].word[j]<<" ";
  counter++;
 }
 ptr++;
 }
}
    
void cal_table()
{
int i,radian_i,abs_i,power_i,ans;
for(i=1;i<=64;i++)
{
radian_i=(3.14/180)*i;
abs_i=abs(sin(radian_i));
power_i=pow(2,32);
ans=power_i *abs_i;
int index=31;
while(ans!=0)
{
 T[i].word[index]=ans%2;
 ans=ans/2;
}
}
}
 

void init_registers()
{
int i;
int p[32]={0,1,1,0,0,1,1,1,0,1,0,0,0,1,0,1,0,0,1,0,0,0,1,1,0,0,0,0,0,0,0,1};
int q[32]={1,1,1,0,1,1,1,1,1,1,0,0,1,1,0,1,1,0,1,0,1,0,1,1,1,0,0,0,1,0,0,1};
int r[32]={1,0,0,1,1,0,0,0,1,0,1,1,1,0,1,0,1,1,0,1,1,1,0,0,1,1,1,1,1,1,1,0};
int s[32]={0,1,1,1,0,1,1,0,0,1,0,1,0,1,0,0,0,0,1,1,0,0,1,0,0,0,0,1,0,0,0,0};
for(i=0;i<32;i++)
{
 a.word[i]=p[i];
 b.word[i]=q[i];
 c.word[i]=r[i];
 d.word[i]=s[i];
}
}

void rounds()
{
int round,k,cntr=0;
getch();

for(round=1;round<=4;round++)
{
for(k=0;k<16;k++)
{
 switch(round)
 {
 case 1:
  result=(b&c|(!b)&d);
  break;
 case 2:
  result=(b&d)|(c&(!d));
  break;
 case 3:
  result=b^c^c;
  break;
 case 4:
  result=c^(b|(!d));
  break;

 }
 result=result+a+X[k]+T[cntr];
 int shift_bits=get_shift_bits(round,k+1);
 result<<shift_bits;
 a=d;d=c;c=b;
 b=b+result;
 cntr++;
 }
   

 cout<<"\n result after round"<<round<<" :";
 display(a);
 display(b);
 display(c);
 display(d);

 }
 cout<<"\n\nmessage digest:\n";
 display(a);
 display(b);
 display(c);
 display(d);
}
   
void MD5_algorithm()
{
char message[100];
cout<<"\n enter input message:";
cin>>message;
convert(message);
padding();
append_length();
div_into_sblk(1);
init_registers();
rounds();
}


void main()
{
 clrscr();
 MD5_algorithm();
 getch();
}