1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.any23.util; 19 20 import java.nio.charset.StandardCharsets; 21 import java.security.MessageDigest; 22 import java.security.NoSuchAlgorithmException; 23 24 /** 25 * Mathematical utility functions. 26 * 27 * @author Michele Mostarda (mostarda@fbk.eu) 28 * @author Davide Palmisano (palmisano@fbk.eu) 29 */ 30 public class MathUtils { 31 32 private MathUtils() { 33 } 34 35 /** 36 * <p> 37 * Create a MD5 <b>weak hash</b> for a given string. 38 * </p> 39 * <p> 40 * <b>N.B. This method MUST never be used in a sensitive context</b>. Examples of such usage include (i) 41 * User-password storage, (ii) Security token generation (used to confirm e-mail when registering on a website, 42 * reset password, etc...), (iii) To compute some message integrity. 43 * </p> 44 * Current usage is limited to {@link org.apache.any23.rdf.RDFUtils#getBNode(String)} which is fine for the creation 45 * of blank node(s). 46 * 47 * @param s 48 * input string to create an MD5 hash for. 49 * 50 * @return a string representation of a MD5 {@link java.security.MessageDigest} 51 */ 52 public static final String md5(String s) { 53 try { 54 MessageDigest md5 = MessageDigest.getInstance("MD5"); 55 md5.reset(); 56 md5.update(s.getBytes(StandardCharsets.UTF_8)); 57 byte[] digest = md5.digest(); 58 StringBuffer result = new StringBuffer(); 59 for (byte b : digest) { 60 result.append(Integer.toHexString(0xFF & b)); 61 } 62 return result.toString(); 63 } catch (NoSuchAlgorithmException e) { 64 throw new RuntimeException("Should never happen, MD5 is supported", e); 65 } 66 } 67 68 }