/magstudentportal/trunk

/* c-basic-offset: 2; tab-width: 2; indent-tabs-mode: nil

 * vi: set shiftwidth=2 tabstop=2 expandtab:

 * :indentSize=2:tabSize=2:noTabs=true:

 */

package common;

import org.bouncycastle.jcajce.provider.digest.*;

import org.bouncycastle.util.encoders.*;

import java.security.MessageDigestSpi;

public class

Utils {

  private Utils () {};

  /**

   * A hash function that salts the password

   * in a way that is pseudo dynamic.

   * 

   * @param t the text to salt

   * @param s the salt

   * @return

   */

  static public String

  real_hash_func (String t, String s) {

    int a = t.getBytes()[0];

    int b = s.getBytes()[a % s.length()] % s.length ();

    StringBuilder sb = new StringBuilder ();

    sb.append (t).insert (b, s);

    SHA3.DigestSHA3 md = new SHA3.DigestSHA3 (512);

    try {

      md.update (sb.toString().getBytes("UTF-8"));

    } catch (Exception e) {

     md.update (sb.toString().getBytes());

    }

    return Hex.toHexString (md.digest ());

  }

  /**

   * Hash a text with a salt.

   * 

   * @param t

   * @return

   */

  static public String

  hash_func (String t) {

    return real_hash_func(t, common.Config.PW_SALT);

  }

}