Product Cipher using JAVA

import java.util.*;
public class product_cipher
{
public static void main(String args[]) {
int sub_key, len, i, x=0, y=0, j=0, z=0;
String pt, cipher;
Scanner sc = new Scanner(System.in);
System.out.println("\nEnter Plain text message");
pt = sc.nextLine();
pt = pt.toUpperCase();
len = pt.length();
char[] c1 = new char[len];
char[] ct = new char[len];
char[] rfc = new char[len];
c1 = pt.toCharArray();
System.out.println("\nEnter Key value for substitution cipher");
sub_key = sc.nextInt();
System.out.println("...........ENCRYPTION............ \nPlain Text:- "+pt);
for(i=0;i<len;i++)
{
x = (c1[i]+sub_key);
if(x>90) {
y = x-90;
ct[i] = (char)(65+(y-1)); }
else
ct[i] = (char)(x);
}
for(i=0;i<len;i=i+2)
{
rfc[j]=ct[i];
j++;
}
for(i=1;i<len;i=i+2)
{
rfc[j]=ct[i];
j++;
}
cipher = new String(rfc);
System.out.println("Cipher Text:- "+cipher);
System.out.println(".........DECRYPTION........\n CIPHER TEXT:- "+cipher);
len = cipher.length();
if(len%2!=0) {
z = (len/2);
z = z+1;}
else
z = (len/2);
rfc = cipher.toCharArray();
j=z;
for(i=0, x=0;i<z && j<len&& x<len;i++,j++) {
ct[x] = rfc[i];
x++;
ct[x] = rfc[j];
x++;
}
for(i=0;i<len;i++)
{
x = (ct[i]-sub_key);
if(x<65) {
y = 65-x;
rfc[i] = (char)(90-(y-1)); }
else
rfc[i] = (char)(x);

}
cipher = new String(rfc);
System.out.println("PLAIN TEXT:- "+cipher);
}
}

..........................................OUTPUT..............................................


Enter Plain text message
Avinash

Enter Key value for substitution cipher
5

...........ENCRYPTION............

Plain Text:- AVINASH
Cipher Text:- FNFMASX

.........DECRYPTION........

CIPHER TEXT:- FNFMASX
PLAIN TEXT:- AVINASH