001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
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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 &quot;XML Encryption Syntax and Processing&quot; 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}