Check password based on MD5 : MD5 Message Digest algorithm  « Security « Java Tutorial

1. Java Tutorial
2. Security
3. MD5 Message Digest algorithm

import java.io.BufferedReader;
import java.io.FileReader;
import java.security.MessageDigest;

public class MainClass {
  public static void main(String args[]) throws Exception {
    String name = "";
    String passwd = "";
    BufferedReader in = new BufferedReader(new FileReader("passwd.txt"));
    while ((name = in.readLine()) != null) {
      passwd = in.readLine();
      if (name.equals(args[0])) {
        break;
      }
    }

    MessageDigest m = MessageDigest.getInstance("MD5");
    m.update(args[1].getBytes("UTF8"));
    byte s[] = m.digest();
    String result = "";
    for (int i = 0; i < s.length; i++) {
      result += Integer.toHexString((0x000000ff & s[i]) | 0xffffff00).substring(6);
    }

    System.out.println(name.equals(args[0]) && result.equals(passwd));
  }
}