substitution cipher

CIPHER

program:
import java.io.*;
import java.util.*;
public class SubstitutionCipher
{
    static Scanner sc = new Scanner(System.in);
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    public static void main(String[] args)
    throws IOException
    {
        String a = "abcdefghijklmnopqrstuvwxyz";
        String b = "zyxwvutsrqponmlkjihgfedcba";
        System.out.print("Enter any string:");
        String str = br.readLine();
        String decrypt = "";
        char c;
        for(int i=0; i<str.length(); i++)
        {
            c = str.charAt(i);
            int j = a.indexOf(c);
            decrypt = decrypt + b.charAt(j);
        }
        System.out.println("The encrypted data is:" + decrypt);
    }
}

OUTPUT:
Enter any string: aceho
The encrypted data is: zxvsl