An extremely lolly easy encryption algorithm by Amogh Kulkarni

Amigho.java

import java.util.*;

public class Amigho
{
	
	public static boolean isUpper(char c){
		return (c>='A'&&c<='Z');
	}
	
	public static boolean isLower(char c){
		return (c>='a'&&c<='z');
	}
	
	/*Encrypt*/
	public static String reverse(String s){
		char ub, lb;
		StringBuilder sb = new StringBuilder();
		for(char c : s.toCharArray()){
			ub = isUpper(c)?'Z':'z';
			lb = isUpper(c)?'A':'a';
			sb.append((char)(ub+lb-c));
		}
		return sb.toString();
	}
	
	public static String ascii(String s){
		StringBuilder sb = new StringBuilder();
		for(char c : s.toCharArray()){
			sb.append((int)c+420);
		}
		return sb.toString();
	}
	
	public static String rotate(String s,int n){
		StringBuilder sb = new StringBuilder(s);
		for(;n>0;n--){
			sb.insert(0, sb.charAt(sb.length()-1));
			sb.deleteCharAt(sb.length()-1);
		}
		return sb.toString();
	}
	
	public static String encrypt(String s){
		return rotate(ascii(reverse(s)), 13);
	}
	
	/*Decryption*/
	
	public static String deascii(String s){
		StringBuilder sb = new StringBuilder();
		for(int i = 0; i <=s.length()-3; i+=3){
			sb.append((char)(Integer.parseInt(s.substring(i,i+3))-420));
		}
		return sb.toString();
	}
	
	public static String derotate(String s,int n){
		StringBuilder sb = new StringBuilder(s);
		for(;n>0;n--){
			sb.insert(sb.length(), sb.charAt(0));
			sb.deleteCharAt(0);
		}
		return sb.toString();
	}
	
	public static String decrypt(String s){
		return reverse(deascii(derotate(s,13)));
	}
	
	
	public static void main(String[] args)
	{
		
		Scanner input = new Scanner(System.in);
		String s = input.nextLine();
		System.out.println("String   : "+s);
		System.out.println("\nEncryption:\n");
		System.out.println(s);
		System.out.println("Reversed : "+reverse(s));
		System.out.println("ASCII+   : "+ascii(reverse(s)));
		s = encrypt(s);
		System.out.println("Rotated  : "+s+" (Encrypted)");
		
		System.out.println("\nDecryption:\n");
		System.out.println(s);
		System.out.println("DeRotated : "+derotate(s,13));
		System.out.println("DeASCII   : "+deascii(derotate(s,13)));
		System.out.println("Reversed  : "+decrypt(s)+" (Decrypted)");
		
	}
}