Java tutorial
/* * Copyright (c) 1996, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.security; /** * The Key interface is the top-level interface for all keys. It * defines the functionality shared by all key objects. All keys * have three characteristics: * * <UL> * * <LI>An Algorithm * * <P>This is the key algorithm for that key. The key algorithm is usually * an encryption or asymmetric operation algorithm (such as DSA or * RSA), which will work with those algorithms and with related * algorithms (such as MD5 with RSA, SHA-1 with RSA, Raw DSA, etc.) * The name of the algorithm of a key is obtained using the * {@link #getAlgorithm() getAlgorithm} method. * * <LI>An Encoded Form * * <P>This is an external encoded form for the key used when a standard * representation of the key is needed outside the Java Virtual Machine, * as when transmitting the key to some other party. The key * is encoded according to a standard format (such as * X.509 {@code SubjectPublicKeyInfo} or PKCS#8), and * is returned using the {@link #getEncoded() getEncoded} method. * Note: The syntax of the ASN.1 type {@code SubjectPublicKeyInfo} * is defined as follows: * * <pre> * SubjectPublicKeyInfo ::= SEQUENCE { * algorithm AlgorithmIdentifier, * subjectPublicKey BIT STRING } * * AlgorithmIdentifier ::= SEQUENCE { * algorithm OBJECT IDENTIFIER, * parameters ANY DEFINED BY algorithm OPTIONAL } * </pre> * * For more information, see * <a href="http://tools.ietf.org/html/rfc5280">RFC 5280: * Internet X.509 Public Key Infrastructure Certificate and CRL Profile</a>. * * <LI>A Format * * <P>This is the name of the format of the encoded key. It is returned * by the {@link #getFormat() getFormat} method. * * </UL> * * Keys are generally obtained through key generators, certificates, * key stores or other classes used to manage keys. * Keys may also be obtained from key specifications (transparent * representations of the underlying key material) through the use of a key * factory (see {@link KeyFactory}). * * <p> A Key should use KeyRep as its serialized representation. * Note that a serialized Key may contain sensitive information * which should not be exposed in untrusted environments. See the * <a href="{@docRoot}/../specs/serialization/security.html"> * Security Appendix</a> * of the Serialization Specification for more information. * * @see PublicKey * @see PrivateKey * @see KeyPair * @see KeyPairGenerator * @see KeyFactory * @see KeyRep * @see java.security.spec.KeySpec * @see Identity * @see Signer * * @author Benjamin Renaud * @since 1.1 */ public interface Key extends java.io.Serializable { // Declare serialVersionUID to be compatible with JDK1.1 /** * The class fingerprint that is set to indicate * serialization compatibility with a previous * version of the class. * * @deprecated A {@code serialVersionUID} field in an interface is * ineffectual. Do not use; no replacement. */ @Deprecated @SuppressWarnings("serial") static final long serialVersionUID = 6603384152749567654L; /** * Returns the standard algorithm name for this key. For * example, "DSA" would indicate that this key is a DSA key. * See the key related sections (KeyFactory, KeyGenerator, * KeyPairGenerator, and SecretKeyFactory) in the <a href= * "{@docRoot}/../specs/security/standard-names.html"> * Java Security Standard Algorithm Names Specification</a> * for information about standard key algorithm names. * * @return the name of the algorithm associated with this key. */ public String getAlgorithm(); /** * Returns the name of the primary encoding format of this key, * or null if this key does not support encoding. * The primary encoding format is * named in terms of the appropriate ASN.1 data format, if an * ASN.1 specification for this key exists. * For example, the name of the ASN.1 data format for public * keys is <I>SubjectPublicKeyInfo</I>, as * defined by the X.509 standard; in this case, the returned format is * {@code "X.509"}. Similarly, * the name of the ASN.1 data format for private keys is * <I>PrivateKeyInfo</I>, * as defined by the PKCS #8 standard; in this case, the returned format is * {@code "PKCS#8"}. * * @return the primary encoding format of the key. */ public String getFormat(); /** * Returns the key in its primary encoding format, or null * if this key does not support encoding. * * @return the encoded key, or null if the key does not support * encoding. */ public byte[] getEncoded(); }