001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.shiro.crypto; 020 021/** 022 * A {@code CipherPaddingScheme} represents well-known 023 * <a href="http://en.wikipedia.org/wiki/Padding_(cryptography)">padding schemes</a> supported by JPA providers in a 024 * type-safe manner. 025 * <p/> 026 * When encrypted data is transferred, it is usually desirable to ensure that all 'chunks' transferred are a fixed-length: 027 * different length blocks might give cryptanalysts clues about what the data might be, among other reasons. Of course 028 * not all data will convert to neat fixed-length blocks, so padding schemes are used to 'fill in' (pad) any remaining 029 * space with unintelligible data. 030 * <p/> 031 * Padding schemes can be used in both asymmetric key ciphers as well as symmetric key ciphers (e.g. block ciphers). 032 * Block-ciphers especially regularly use padding schemes as they are based on the notion of fixed-length block sizes. 033 * 034 * @see <a href="http://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia: Cryptographic Padding</a> 035 * @since 1.0 036 */ 037public enum PaddingScheme { 038 039 /** 040 * No padding. Useful when the block size is 8 bits for block cipher streaming operations. (Because 041 * a byte is the most primitive block size, there is nothing to pad). 042 */ 043 NONE("NoPadding"), 044 045 /** 046 * Padding scheme as defined in the W3C's "XML Encryption Syntax and Processing" document, 047 * <a href="http://www.w3.org/TR/xmlenc-core/#sec-Alg-Block">Section 5.2 - Block Encryption Algorithms</a>. 048 */ 049 ISO10126("ISO10126Padding"), 050 051 /** 052 * Optimal Asymmetric Encryption Padding defined in RSA's <a href="http://en.wikipedia.org/wiki/PKCS1">PKSC#1 053 * standard</a> (aka <a href="http://tools.ietf.org/html/rfc3447">RFC 3447</a>). 054 * <p/> 055 * <b>NOTE:</b> using this padding requires initializing {@link javax.crypto.Cipher Cipher} instances with a 056 * {@link javax.crypto.spec.OAEPParameterSpec OAEPParameterSpec} object which provides the 1) message digest and 057 * 2) mask generation function to use for the scheme. 058 * <h3>Convenient Alternatives</h3> 059 * While using this scheme enables you full customization of the message digest + mask generation function 060 * combination, it does require the extra burden of providing your own {@code OAEPParameterSpec} object. This is 061 * often unnecessary, because most combinations are fairly standard. These common combinations are pre-defined 062 * in this enum in the {@code OAEP}* variants. 063 * <p/> 064 * If you find that these common combinations still do not meet your needs, then you will need to 065 * specify your own message digest and mask generation function, either as an {@code OAEPParameterSpec} object 066 * during Cipher initialization or, maybe more easily, in the scheme name directly. If you want to use scheme name 067 * approach, the name format is specified in the 068 * <a href="http://java.sun.com/javase/6/docs/technotes/guides/security/StandardNames.html">Standard Names</a> 069 * document in the <code>Cipher Algorithm Padding</code> section. 070 * 071 * @see #OAEPWithMd5AndMgf1 072 * @see #OAEPWithSha1AndMgf1 073 * @see #OAEPWithSha256AndMgf1 074 * @see #OAEPWithSha384AndMgf1 075 * @see #OAEPWithSha512AndMgf1 076 */ 077 OAEP("OAEPPadding"), 078 079 /** 080 * Optimal Asymmetric Encryption Padding with {@code MD5} message digest and {@code MGF1} mask generation function. 081 * <p/> 082 * This is a convenient pre-defined OAEP padding scheme that embeds the message digest and mask generation function. 083 * When using this padding scheme, there is no need to init the {@code Cipher} instance with an 084 * {@link javax.crypto.spec.OAEPParameterSpec OAEPParameterSpec} object, as it is already 'built in' to the scheme 085 * name (unlike the {@link #OAEP OAEP} scheme, which requires a bit more work). 086 */ 087 OAEPWithMd5AndMgf1("OAEPWithMD5AndMGF1Padding"), 088 089 /** 090 * Optimal Asymmetric Encryption Padding with {@code SHA-1} message digest and {@code MGF1} mask generation function. 091 * <p/> 092 * This is a convenient pre-defined OAEP padding scheme that embeds the message digest and mask generation function. 093 * When using this padding scheme, there is no need to init the {@code Cipher} instance with an 094 * {@link javax.crypto.spec.OAEPParameterSpec OAEPParameterSpec} object, as it is already 'built in' to the scheme 095 * name (unlike the {@link #OAEP OAEP} scheme, which requires a bit more work). 096 */ 097 OAEPWithSha1AndMgf1("OAEPWithSHA-1AndMGF1Padding"), 098 099 /** 100 * Optimal Asymmetric Encryption Padding with {@code SHA-256} message digest and {@code MGF1} mask generation function. 101 * <p/> 102 * This is a convenient pre-defined OAEP padding scheme that embeds the message digest and mask generation function. 103 * When using this padding scheme, there is no need to init the {@code Cipher} instance with an 104 * {@link javax.crypto.spec.OAEPParameterSpec OAEPParameterSpec} object, as it is already 'built in' to the scheme 105 * name (unlike the {@link #OAEP OAEP} scheme, which requires a bit more work). 106 */ 107 OAEPWithSha256AndMgf1("OAEPWithSHA-256AndMGF1Padding"), 108 109 /** 110 * Optimal Asymmetric Encryption Padding with {@code SHA-384} message digest and {@code MGF1} mask generation function. 111 * <p/> 112 * This is a convenient pre-defined OAEP padding scheme that embeds the message digest and mask generation function. 113 * When using this padding scheme, there is no need to init the {@code Cipher} instance with an 114 * {@link javax.crypto.spec.OAEPParameterSpec OAEPParameterSpec} object, as it is already 'built in' to the scheme 115 * name (unlike the {@link #OAEP OAEP} scheme, which requires a bit more work). 116 */ 117 OAEPWithSha384AndMgf1("OAEPWithSHA-384AndMGF1Padding"), 118 119 /** 120 * Optimal Asymmetric Encryption Padding with {@code SHA-512} message digest and {@code MGF1} mask generation function. 121 * <p/> 122 * This is a convenient pre-defined OAEP padding scheme that embeds the message digest and mask generation function. 123 * When using this padding scheme, there is no need to init the {@code Cipher} instance with an 124 * {@link javax.crypto.spec.OAEPParameterSpec OAEPParameterSpec} object, as it is already 'built in' to the scheme 125 * name (unlike the {@link #OAEP OAEP} scheme, which requires a bit more work). 126 */ 127 OAEPWithSha512AndMgf1("OAEPWithSHA-512AndMGF1Padding"), 128 129 /** 130 * Padding scheme used with the {@code RSA} algorithm defined in RSA's 131 * <a href="http://en.wikipedia.org/wiki/PKCS1">PKSC#1 standard</a> (aka 132 * <a href="http://tools.ietf.org/html/rfc3447">RFC 3447</a>). 133 */ 134 PKCS1("PKCS1Padding"), 135 136 /** 137 * Padding scheme defined in RSA's <a href="http://www.rsa.com/rsalabs/node.asp?id=2127">Password-Based 138 * Cryptography Standard</a>. 139 */ 140 PKCS5("PKCS5Padding"), 141 142 /** 143 * Padding scheme defined in the <a href="http://www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt">SSL 144 * 3.0 specification</a>, section <code>5.2.3.2 (CBC block cipher)</code>. 145 */ 146 SSL3("SSL3Padding"); 147 148 private final String transformationName; 149 150 private PaddingScheme(String transformationName) { 151 this.transformationName = transformationName; 152 } 153 154 /** 155 * Returns the actual string name to use when building the {@link javax.crypto.Cipher Cipher} 156 * {@code transformation string}. 157 * 158 * @return the actual string name to use when building the {@link javax.crypto.Cipher Cipher} 159 * {@code transformation string}. 160 * @see javax.crypto.Cipher#getInstance(String) 161 */ 162 public String getTransformationName() { 163 return this.transformationName; 164 } 165}