HWID thing

package xyz.terrific;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.security.*;
import java.util.Arrays;
import java.util.Base64;

public class Main {
    public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException {

        String command = "wmic baseboard get serialnumber";
        StringBuilder serialNumber = new StringBuilder();

        try {
            Process SerialNumberProcess = Runtime.getRuntime().exec(command);
            InputStreamReader ISR = new InputStreamReader(SerialNumberProcess.getInputStream());
            BufferedReader br = new BufferedReader(ISR);
            String line;
            while ((line = br.readLine()) != null) {
                serialNumber.append(line);
            }
            SerialNumberProcess.waitFor();
            br.close();
        } catch (Exception e) {
            e.printStackTrace();
        }


        StringBuilder hwid_builder = new StringBuilder();
        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
        keyGen.initialize(1024*4);
        KeyPair pair = keyGen.generateKeyPair();

        hwid_builder.append(cipherEncrypt("HWID by TerrificTable", "RSA/ECB/PKCS1Padding", pair));
        hwid_builder.append(hash(Arrays.toString(add(hwid_builder.toString().getBytes(), serialNumber.toString().getBytes())), "SHA-512"));

        String hashText = hash(new String(foreach(hwid_builder.toString().getBytes())), "SHA-512");
        String hwid = Base64.getEncoder().encodeToString(Base64.getEncoder().encode(hashText.getBytes()));


        System.out.println(hwid);
    }


    public static String cipherEncrypt(String s, String algorithm, KeyPair pair) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.ENCRYPT_MODE, pair.getPublic());
        return cipherEncrypt(s, cipher);
    }
    public static String cipherEncrypt(String s, Cipher cipher) throws IllegalBlockSizeException, BadPaddingException {
        return Arrays.toString(cipher.doFinal(s.getBytes()));
    }


    private static byte[] add(byte[] a, byte[] b) {
        int aLen = a.length;
        int bLen = b.length;
        int cLen = aLen + bLen;
        byte[] c = new byte[cLen];
        for (int i=0; i < cLen; i++)
            c[i] = (byte) (a[i % aLen] ^ b[i % bLen]);
        return c;
    }

    private static char[] foreach(byte[] bytes) {
        char[] chars = new char[bytes.length * 100];
        for (int i=0; i < bytes.length; i++) chars[i] = (char) bytes[i];
        for (int aChar : chars)
            chars[aChar] =
                    (char) (chars[aChar] ^ (aChar ^ chars[aChar]) + (int)(Math.random() * 100 / Math.random()));
        return chars;
    }

    public static String hash(String s, String algorithm) throws NoSuchAlgorithmException {
        return hash(s, algorithm, "0");
    }

    public static String hash(String s, String algorithm, String replacement) throws NoSuchAlgorithmException {
        MessageDigest hasher = MessageDigest.getInstance(algorithm);
        byte[] hashtext = hasher.digest(s.getBytes());
        BigInteger bigInt = new BigInteger(1, hashtext);
        StringBuilder res = new StringBuilder(bigInt.toString(32));
        while (res.length() < 128) res.insert(0, replacement);
        return res.toString();
    }
}