I need algorithm for this code

Part II - Decryption: import java.util.*: public class Caesarciphereneguan { public static void main(String args[]) { Scanner as = new Scanner(System.in); System.outubxint(" Input the ciphertext message: "); String ciphertext SautextLine(); SxxtementBrint("Enter the shift value: "); int shift = saubextInt (); String desert Message for(int i=0; i = 'a' && alphabet = 'A' && alphabet