playfair
import java.util.Scanner;
public class Playfair {

	public static void main(String args[])
	{  Scanner sc=new Scanner(System.in);
		String kw=sc.next();
		String pt;
		char mat[]=new char[25];
		char matrix[][]=new char[5][5];
		int l,i,j,k,r1=0,r2=0,c1=0,c2=0;
		char c;
		
		mat[0]=kw.charAt(0);
		l=1;
		for(i=1;i<kw.length();i++)
		{System.out.println(kw.charAt(i));
		 for(j=0;j<l;j++)
			 if (mat[j]==kw.charAt(i))
				 break;
		 if (j==l)
			 {mat[j]=kw.charAt(i);l++;}
			 
		}
		for(c='A';c<91;c++)
			
			{
			 if(c=='I')
				 continue;
			//System.out.println(c);
			 //compare and insert
			 for(j=0;j<l;j++)
				 if (mat[j]==c)
					 break;
			 if (j==l)
				 {mat[j]=c;l++;}
				 
			 
			}
		for(j=0;j<25;j++)
			System.out.print(mat[j]+"   ");
		k=0;
		for(i=0;i<5;i++)
			for(j=0;j<5;j++)
			{matrix[i][j]=mat[k++];}
		//printing in the matrix form
		for(i=0;i<5;i++) 
		{
			
		  System.out.println();
			for(j=0;j<5;j++)
			 System.out.print(matrix[i][j]+"  ");
		}
		System.out.println("enter the plain text");
		pt=sc.next();
		char dg[]=new char[25];
		char ct[]=new char[25];
		dg[0]=pt.charAt(0);
		dg[1]=pt.charAt(1);
		for(i=0;i<25;i++)
			if(mat[i]==dg[0])
			{r1=i/5;c1=i%5;}
		for(i=0;i<25;i++)
			if(mat[i]==dg[1])
			{r2=i/5;c2=i%5;}
		if(r1==r2)
			{ct[0]=matrix[r1][(c1+1)%5];
		    ct[1]=matrix[r1][(c2+1)%5];}
		else if(c1==c2)
		{ct[0]=matrix[(r1+1)%5][c1];
	    ct[1]=matrix[(r2+1)%5][c2];}
		else 
		{ct[0]=matrix[r2][c1];
	    ct[1]=matrix[r1][c2];}	
		System.out.println(ct[0]+"  "+ct[1]);
			
			
				
				
		
		
	 }
	}
	
	
	hill cipher 
	
	import java.util.Scanner;
public class HillCipher {
	static int keyMat[][]=new int[3][3];
	static void readKeyMatrix()
	{Scanner sc=new Scanner (System.in);
		int i,j;
	   for(i=0;i<3;i++)
		   for(j=0;j<3;j++)
	         keyMat[i][j]=sc.nextInt();
		
	}
	public static void main(String arg[])
	{
		Scanner sc=new Scanner (System.in);
		String pt;
		System.out.print("enter the plain txt" );
	    pt=sc.next();
		int  i,l,m,ex;
		l=pt.length();
		
		System.out.print(" enter how many characters ? ");
		m=sc.nextInt();
		ex=l%m;
		int a[]=new int[l+ex];
		for(i=0;i<l;i++)
			 a[i]=(int)pt.charAt(i)-65;
		// filling extra values
		for(;i<l+ex;i++)
			a[i]=90;
		for(i=0;i<l+ex;i++)
			System.out.println(a[i]+"  ");
		// multiplication part ciphertext
		readKeyMatrix();
		int j,k;
		int p[][]=new int[m][1];
		int c[][]=new int[m][1];
		for(i=0;i<3;i++)
			p[i][0]=a[i];
		for(i=0;i<3;i++)
			for(j=0;j<1;j++)
			{c[i][j]=0;
			  for(k=0;k<3;k++)
				  c[i][j]+=keyMat[i][k]*p[k][j];
			 	 
			}
		for(int n=0;n<3;n++)
			 System.out.println((char)(c[n][0]%26+65));
			
		
			
	}

}

caesar cipher


class CeasarCipher
{
	// Encrypts text using a shift of s
	public static StringBuffer encrypt(String text, int s)
	{
		StringBuffer result= new StringBuffer();

		for (int i=0; i<text.length(); i++)
		{
			if (Character.isUpperCase(text.charAt(i)))
			{
				char ch = (char)(((int)text.charAt(i) +
								s - 65) % 26 + 65);
				result.append(ch);
			}
			else
			{
				char ch = (char)(((int)text.charAt(i) +
								s - 97) % 26 + 97);
				result.append(ch);
			}
		}
		return result;
	}

	// Driver code
	public static void main(String[] args)
	{
		String text = "cryptography";
		int s = 3;
		System.out.println("Text : " + text);
		System.out.println("Shift : " + s);
		System.out.println("Cipher: " + encrypt(text, s));
	}
}