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 */
017 package org.apache.commons.codec.digest;
018
019 import org.apache.commons.codec.Charsets;
020
021 /**
022 * GNU libc crypt(3) compatible hash method.
023 * <p>
024 * See {@link #crypt(String, String)} for further details.
025 * <p>
026 * This class is immutable and thread-safe.
027 *
028 * @version $Id: Crypt.html 889935 2013-12-11 05:05:13Z ggregory $
029 * @since 1.7
030 */
031 public class Crypt {
032
033 /**
034 * Encrypts a password in a crypt(3) compatible way.
035 * <p>
036 * A random salt and the default algorithm (currently SHA-512) are used. See {@link #crypt(String, String)} for
037 * details.
038 *
039 * @param keyBytes
040 * plaintext password
041 * @return hash value
042 * @throws RuntimeException
043 * when a {@link java.security.NoSuchAlgorithmException} is caught.
044 */
045 public static String crypt(byte[] keyBytes) {
046 return crypt(keyBytes, null);
047 }
048
049 /**
050 * Encrypts a password in a crypt(3) compatible way.
051 * <p>
052 * If no salt is provided, a random salt and the default algorithm (currently SHA-512) will be used. See
053 * {@link #crypt(String, String)} for details.
054 *
055 * @param keyBytes
056 * plaintext password
057 * @param salt
058 * salt value
059 * @return hash value
060 * @throws IllegalArgumentException
061 * if the salt does not match the allowed pattern
062 * @throws RuntimeException
063 * when a {@link java.security.NoSuchAlgorithmException} is caught.
064 */
065 public static String crypt(byte[] keyBytes, String salt) {
066 if (salt == null) {
067 return Sha2Crypt.sha512Crypt(keyBytes);
068 } else if (salt.startsWith(Sha2Crypt.SHA512_PREFIX)) {
069 return Sha2Crypt.sha512Crypt(keyBytes, salt);
070 } else if (salt.startsWith(Sha2Crypt.SHA256_PREFIX)) {
071 return Sha2Crypt.sha256Crypt(keyBytes, salt);
072 } else if (salt.startsWith(Md5Crypt.MD5_PREFIX)) {
073 return Md5Crypt.md5Crypt(keyBytes, salt);
074 } else {
075 return UnixCrypt.crypt(keyBytes, salt);
076 }
077 }
078
079 /**
080 * Calculates the digest using the strongest crypt(3) algorithm.
081 * <p>
082 * A random salt and the default algorithm (currently SHA-512) are used.
083 *
084 * @see #crypt(String, String)
085 * @param key
086 * plaintext password
087 * @return hash value
088 * @throws RuntimeException
089 * when a {@link java.security.NoSuchAlgorithmException} is caught.
090 */
091 public static String crypt(String key) {
092 return crypt(key, null);
093 }
094
095 /**
096 * Encrypts a password in a crypt(3) compatible way.
097 * <p>
098 * The exact algorithm depends on the format of the salt string:
099 * <ul>
100 * <li>SHA-512 salts start with $6$ and are up to 16 chars long.
101 * <li>SHA-256 salts start with $5$ and are up to 16 chars long
102 * <li>MD5 salts start with "$1$" and are up to 8 chars long
103 * <li>DES, the traditional UnixCrypt algorithm is used else with only 2 chars
104 * <li>Only the first 8 chars of the passwords are used in the DES algorithm!
105 * </ul>
106 * The magic strings "$apr1$" and "$2a$" are not recognised by this method as its output should be identical with
107 * that of the libc implementation.
108 * <p>
109 * The rest of the salt string is drawn from the set [a-zA-Z0-9./] and is cut at the maximum length of if a "$"
110 * sign is encountered. It is therefore valid to enter a complete hash value as salt to e.g. verify a password
111 * with:
112 *
113 * <pre>
114 * storedPwd.equals(crypt(enteredPwd, storedPwd))
115 * </pre>
116 * <p>
117 * The resulting string starts with the marker string ($6$), continues with the salt value and ends with a "$" sign
118 * followed by the actual hash value. For DES the string only contains the salt and actual hash. It's total length
119 * is dependent on the algorithm used:
120 * <ul>
121 * <li>SHA-512: 106 chars
122 * <li>SHA-256: 63 chars
123 * <li>MD5: 34 chars
124 * <li>DES: 13 chars
125 * </ul>
126 * <p>
127 * Example:
128 *
129 * <pre>
130 * crypt("secret", "$1$xxxx") => "$1$xxxx$aMkevjfEIpa35Bh3G4bAc."
131 * crypt("secret", "xx") => "xxWAum7tHdIUw"
132 * </pre>
133 * <p>
134 * This method comes in a variation that accepts a byte[] array to support input strings that are not encoded in
135 * UTF-8 but e.g. in ISO-8859-1 where equal characters result in different byte values.
136 *
137 * @see "The man page of the libc crypt (3) function."
138 * @param key
139 * plaintext password as entered by the used
140 * @param salt
141 * salt value
142 * @return hash value, i.e. encrypted password including the salt string
143 * @throws IllegalArgumentException
144 * if the salt does not match the allowed pattern
145 * @throws RuntimeException
146 * when a {@link java.security.NoSuchAlgorithmException} is caught. *
147 */
148 public static String crypt(String key, String salt) {
149 return crypt(key.getBytes(Charsets.UTF_8), salt);
150 }
151 }