001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.vfs2.util; 018 019import javax.crypto.Cipher; 020import javax.crypto.spec.SecretKeySpec; 021 022/** 023 * Allows passwords to be encrypted and decrypted. 024 * <p> 025 * Warning: This uses AES128 with a fixed encryption key. This is only an obfuscation no cryptographic secure 026 * protection. 027 * 028 * @since 2.0 029 */ 030public class DefaultCryptor implements Cryptor { 031 private static final char[] HEX_CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 032 'F' }; 033 034 private static final byte[] KEY_BYTES = { 0x41, 0x70, 0x61, 0x63, 0x68, 0x65, 0x43, 0x6F, 0x6D, 0x6D, 0x6F, 0x6E, 035 0x73, 0x56, 0x46, 0x53 }; 036 037 private static final int INDEX_NOT_FOUND = -1; 038 039 private static final int BITS_IN_HALF_BYTE = 4; 040 041 private static final char MASK = 0x0f; 042 043 /** 044 * Encrypt the plain text password. 045 * <p> 046 * Warning: This uses AES128 with a fixed encryption key. This is only an obfuscation no cryptographic secure 047 * protection. 048 * 049 * @param plainKey The password. 050 * @return The encrypted password String. 051 * @throws Exception If an error occurs. 052 */ 053 @Override 054 public String encrypt(final String plainKey) throws Exception { 055 final byte[] input = plainKey.getBytes(); 056 final SecretKeySpec key = new SecretKeySpec(KEY_BYTES, "AES"); 057 058 final Cipher cipher = Cipher.getInstance("AES"); 059 060 // encryption pass 061 cipher.init(Cipher.ENCRYPT_MODE, key); 062 063 final byte[] cipherText = new byte[cipher.getOutputSize(input.length)]; 064 int ctLength = cipher.update(input, 0, input.length, cipherText, 0); 065 ctLength += cipher.doFinal(cipherText, ctLength); 066 return encode(cipherText); 067 } 068 069 /** 070 * Decrypts the password. 071 * 072 * @param encryptedKey the encrypted password. 073 * @return The plain text password. 074 * @throws Exception If an error occurs. 075 */ 076 @Override 077 public String decrypt(final String encryptedKey) throws Exception { 078 final SecretKeySpec key = new SecretKeySpec(KEY_BYTES, "AES"); 079 final Cipher cipher = Cipher.getInstance("AES"); 080 cipher.init(Cipher.DECRYPT_MODE, key); 081 final byte[] decoded = decode(encryptedKey); 082 final byte[] plainText = new byte[cipher.getOutputSize(decoded.length)]; 083 int ptLength = cipher.update(decoded, 0, decoded.length, plainText, 0); 084 ptLength += cipher.doFinal(plainText, ptLength); 085 return new String(plainText).substring(0, ptLength); 086 } 087 088 /** Hex-encode bytes. */ 089 private String encode(final byte[] bytes) { 090 final StringBuilder builder = new StringBuilder(); 091 092 for (final byte b : bytes) { 093 builder.append(HEX_CHARS[(b >> BITS_IN_HALF_BYTE) & MASK]); 094 builder.append(HEX_CHARS[b & MASK]); 095 } 096 return builder.toString(); 097 } 098 099 /** Decodes Hey-Bytes. */ 100 private byte[] decode(final String str) { 101 final int length = str.length() / 2; 102 final byte[] decoded = new byte[length]; 103 final char[] chars = str.toCharArray(); 104 int index = 0; 105 for (int i = 0; i < chars.length; ++i) { 106 final int id1 = indexOf(HEX_CHARS, chars[i]); 107 if (id1 == -1) { 108 throw new IllegalArgumentException( 109 "Character " + chars[i] + " at position " + i + " is not a valid hexidecimal character"); 110 } 111 final int id2 = indexOf(HEX_CHARS, chars[++i]); 112 if (id2 == -1) { 113 throw new IllegalArgumentException( 114 "Character " + chars[i] + " at position " + i + " is not a valid hexidecimal character"); 115 } 116 decoded[index++] = (byte) ((id1 << BITS_IN_HALF_BYTE) | id2); 117 } 118 return decoded; 119 } 120 121 private int indexOf(final char[] array, final char valueToFind) { 122 if (array == null) { 123 return INDEX_NOT_FOUND; 124 } 125 for (int i = 0; i < array.length; i++) { 126 if (valueToFind == array[i]) { 127 return i; 128 } 129 } 130 return INDEX_NOT_FOUND; 131 } 132}