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import java.util.Scanner;

public class FourSquareCipher{

//aggregate 2-D char array (10 X 10)

static char[][] aggregate = new char[10][10];

//TL,TR,BL,BR 2-D char array (each one 5 X 5)

static char[][] TL=new char[5][5], TR=new char[5][5];

static char[][] BL=new char[5][5], BR=new char[5][5];

//encryption function

static String encrypt(String pt, String key1, String key2) {

String encpt = new String("");

int n=-1;

for(int i=0;i<key1.length();i++) {

n+=1;

n%=5;

int m=(int)(i/5);

TR[m][n]=key1.charAt(i);

}

n=-1;

for(int i=0;i<key2.length();i++) {

n+=1;

n%=5;

int m=(int)(i/5);

BL[m][n]=key2.charAt(i);

}

int num = 64;

for(int i=0;i<5;i++)

for(int j=0;j<5;j++) {

num++;

if(num==74)

num++;

TL[i][j]=(char)num;

BR[i][j]=(char)num;

}

String seq = new String("");

for(int i=0;i<5;i++) {

for(int j=0;j<10;j++) {

if(j>4) {

int k=j-5;

seq=seq+TR[i][k];

}

else {

seq=seq+TL[i][j];

}

}

}

for(int i=0;i<5;i++) {

for(int j=0;j<10;j++) {

if(j>4) {

int k=j-5;

seq=seq+BR[i][k];

}

else {

seq=seq+BL[i][j];

}

}

}

int ctr=-1;

for(int i=0;i<10;i++)

for(int j=0;j<10;j++) {

ctr++;

aggregate[i][j]=seq.charAt(ctr);

}

for(int i=0;i<pt.length();i=i+2) {

int row=0, col=0;

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(TL[j][k]==pt.charAt(i)) {

row = j;

break;

}

if(row!=0)

break;

}

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(BR[j][k]==pt.charAt(i+1)) {

col = k+5;

break;

}

if(col!=0)

break;

}

encpt = encpt + Character.toString(aggregate[row][col]);

row = 0; col = 0;

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(BR[j][k]==pt.charAt(i+1)) {

row = j+5;

break;

}

if(row!=0)

break;

}

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(TL[j][k]==pt.charAt(i)) {

col = k;

break;

}

if(col!=0)

break;

}

encpt = encpt + Character.toString(aggregate[row][col]);

}

return encpt;

}

//decryption function

static String decrypt(String encpt, String key1, String key2) {

String decpt = new String("");

for(int i=0; i<encpt.length(); i=i+2) {

int row=0, col=0;

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(TR[j][k]==encpt.charAt(i)) {

row = j;

break;

}

if(row!=0)

break;

}

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(BL[j][k]==encpt.charAt(i+1)) {

col = k;

break;

}

if(col!=0)

break;

}

decpt = decpt + Character.toString(aggregate[row][col]);

row = 0; col = 0;

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(BL[j][k]==encpt.charAt(i+1)) {

row = j+5;

break;

}

if(row!=0)

break;

}

for(int j=0;j<5;j++)

for(int k=0;k<5;k++) {

if(TR[j][k]==encpt.charAt(i)) {

col = k+5;

break;

}

if(col!=0)

break;

}

decpt = decpt + Character.toString(aggregate[row][col]);

}

return decpt;

}

//main function

public static void main(String[] args) {

System.out.print("Enter plaintext: ");

Scanner scan = new Scanner(System.in);

String pt = scan.nextLine();

System.out.print("Enter key 1: ");

String key1 = scan.nextLine();

System.out.print("Enter key 2: ");

String key2 = scan.nextLine();

String encpt = encrypt(pt,key1,key2);

String decpt = decrypt(encpt,key1,key2);

System.out.println("Encrypted text: "+encpt);

System.out.println("Decrypted text: "+decpt);

scan.close();

}

}