ideal sn

import java.math.BigInteger;
import java.util.Date;
import java.util.Random;
import java.util.zip.CRC32;

public class Sn
{
  /**
  * @param s
  * @param i
  * @param bytes
  * @return
  */
  public static short getCRC(String s, int i, byte bytes[])
  {
    CRC32 crc32 = new CRC32();
    if (s != null)
    {
      for (int j = 0; j < s.length(); j++)
      {
        char c = s.charAt(j);
        crc32.update(c);
      }
    }
    crc32.update(i);
    crc32.update(i >> 8);
    crc32.update(i >> 16);
    crc32.update(i >> 24);
    for (int k = 0; k < bytes.length - 2; k++)
    {
      byte byte0 = bytes[k];
      crc32.update(byte0);
    }
    return (short) (int) crc32.getValue();
  }

  /**
  * @param biginteger
  * @return String
  */
  public static String encodeGroups(BigInteger biginteger)
  {
    BigInteger beginner1 = BigInteger.valueOf(0x39aa400L);
    StringBuilder sb = new StringBuilder();
    for (int i = 0; biginteger.compareTo(BigInteger.ZERO) != 0; i++)
    {
      int j = biginteger.mod(beginner1).intValue();
      String s1 = encodeGroup(j);
      if (i > 0)
      {
        sb.append("-");
      }
      sb.append(s1);
      biginteger = biginteger.divide(beginner1);
    }
    return sb.toString();
  }

  /**
  * @param i
  * @return
  */
  public static String encodeGroup(int i)
  {
    StringBuilder sb = new StringBuilder();
    for (int j = 0; j < 5; j++)
    {
      int k = i % 36;
      char c;
      if (k < 10)
      {
        c = (char) (48 + k);
      }
      else
      {
        c = (char) ((65 + k) - 10);
      }
      sb.append(c);
      i /= 36;
    }
    return sb.toString();
  }

  /**
  * @param name
  * @param days
  * @param id
  * @return
  */
  public static String MakeKey(String name, int days, int id)
  {
    id %= 100000;
    byte bkey[] = new byte[12];
    bkey[0] = (byte) 1; // Product type: IntelliJ IDEA is 1
    bkey[1] = 14; // version
    Date d = new Date();
    long ld = (d.getTime() >> 16);
    bkey[2] = (byte) (ld & 255);
    bkey[3] = (byte) ((ld >> 8) & 255);
    bkey[4] = (byte) ((ld >> 16) & 255);
    bkey[5] = (byte) ((ld >> 24) & 255);
    days &= 0xffff;
    bkey[6] = (byte) (days & 255);
    bkey[7] = (byte) ((days >> 8) & 255);
    bkey[8] = 105;
    bkey[9] = -59;
    bkey[10] = 0;
    bkey[11] = 0;
    int w = getCRC(name, id % 100000, bkey);
    bkey[10] = (byte) (w & 255);
    bkey[11] = (byte) ((w >> 8) & 255);
    BigInteger pow = new BigInteger("89126272330128007543578052027888001981", 10);
    BigInteger mod = new BigInteger("86f71688cdd2612ca117d1f54bdae029", 16);
    BigInteger k0 = new BigInteger(bkey);
    BigInteger k1 = k0.modPow(pow, mod);
    String s0 = Integer.toString(id);
    String sz = "0";
    while (s0.length() != 5)
    {
      s0 = sz.concat(s0);
    }
    s0 = s0.concat("-");
    String s1 = encodeGroups(k1);
    s0 = s0.concat(s1);
    return s0;
  }

  public static void main(String[] args)
  {
//    if (args.length == 0)
//    {
//      System.err.printf("*** Usage: %s name%n", Test.class.getCanonicalName());
//      System.exit(1);
//    }
      int i=0;
      int a = i +5;
    Random r = new Random();
    System.out.println(MakeKey("weg", 0, r.nextInt(100000)));
  }
}