I don't fully understand the question. What are you going to be using the ciphers for? If you need to actually use one it is quite simple in java. Start with:
Code
Cipher c = Cipher.getInstance("AES");
If you want to understand the cipher then looking at code isn't the right thing. You probably want to look here:
https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Standards-and-Guidelines/documents/aes-development/Rijndael-ammended.pdfhttps://csrc.nist.gov/projects/cryptographic-standards-and-guidelines/archived-crypto-projects/aes-developmentcaesar cipher is easy to understand and to program. I just wrote this program to give you an example:
Code
package com.company;
import java.util.stream.IntStream;
public class Main {
public static void main(String[] args) {
final String input = "My Secret ABCDEFGHIJKLMNOPQRSTUVWXYZ";
final String words = input.toUpperCase();
IntStream.rangeClosed(0, 26).forEach(key -> {
System.out.println(ceasar(words, key));
});
}
private static String ceasar(String words, int key) {
return words.chars()
.map(i -> (char) i == ' ' ? ' ' : (i + key - 65) % 26 + 65)
.collect(StringBuilder::new,
StringBuilder::appendCodePoint,
StringBuilder::append).toString();
}
}