src/java.base/share/classes/java/security/spec/PKCS8EncodedKeySpec.java

/*
 * Copyright (c) 1997, 2025, 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.spec;

import java.security.DEREncodable;

/**
 * This class represents the ASN.1 encoding of a private key,
 * encoded according to the ASN.1 type {@code OneAsymmetricKey}.
 * The {@code OneAsymmetricKey} syntax is defined in the PKCS#8 standard
 * as follows:
 *
 * <pre>
 * OneAsymmetricKey ::= SEQUENCE {
 *   version Version,
 *   privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
 *   privateKey PrivateKey,
 *   attributes       [0] Attributes OPTIONAL,
 *   ...,
 *   [[2: publicKey  [1] PublicKey OPTIONAL ]],
 *   ...
 * }
 *
 * PrivateKeyInfo ::= OneAsymmetricKey
 *
 * Version ::= INTEGER { v1(0), v2(1) }
 *
 * PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier
 *
 * PrivateKey ::= OCTET STRING
 *
 * PublicKey ::= BIT STRING
 *
 * Attributes ::= SET OF Attribute
 * </pre>
 *
 * @author Jan Luehe
 *
 *
 * @see java.security.Key
 * @see java.security.KeyFactory
 * @see KeySpec
 * @see EncodedKeySpec
 * @see X509EncodedKeySpec
 *
 * @spec https://www.rfc-editor.org/info/rfc5958
 *     RFC 5958: Asymmetric Key Packages
 *
 * @since 1.2
 */

public non-sealed class PKCS8EncodedKeySpec extends EncodedKeySpec implements
    DEREncodable {
    /**
     * Creates a new {@code PKCS8EncodedKeySpec} with the given encoded key.
     *
     * @param encodedKey the key, which is assumed to be
     * encoded according to the PKCS #8 standard. The contents of
     * the array are copied to protect against subsequent modification.
     * @throws NullPointerException if {@code encodedKey}
     * is null.
     */
    public PKCS8EncodedKeySpec(byte[] encodedKey) {
        super(encodedKey);
    }

    /**
     * Creates a new {@code PKCS8EncodedKeySpec} with the given encoded key and
     * algorithm. This constructor is useful when subsequent callers of
     * the {@code PKCS8EncodedKeySpec} object might not know the
     * algorithm of the private key.
     *
     * @param encodedKey the key, which is assumed to be
     * encoded according to the PKCS #8 standard. The contents of
     * the array are copied to protect against subsequent modification.
     * @param algorithm the algorithm name of the encoded private key.
     * See the AsymmetricKey Algorithms section in the
     * <a href="{@docRoot}/../specs/security/standard-names.html#asymmetrickey-algorithms">
     * Java Security Standard Algorithm Names Specification</a>
     * for information about standard asymmetric key algorithm names.
     * @spec security/standard-names.html Java Security Standard Algorithm Names
     * @throws NullPointerException if {@code encodedKey}
     * or {@code algorithm} is null.
     * @throws IllegalArgumentException if {@code algorithm} is
     * the empty string {@code ""}
     * @spec security/standard-names.html Java Security Standard Algorithm Names
     * @since 9
     */
    public PKCS8EncodedKeySpec(byte[] encodedKey, String algorithm) {
        super(encodedKey, algorithm);
    }

    /**
     * Returns the key bytes, encoded according to the PKCS #8 standard.
     *
     * @return the PKCS #8 encoding of the key. Returns a new array
     * each time this method is called.
     */
    public byte[] getEncoded() {
        return super.getEncoded();
    }

    /**
     * Returns the name of the encoding format associated with this
     * key specification.
     *
     * @return the string {@code "PKCS#8"}.
     */
    public final String getFormat() {
        return "PKCS#8";
    }
}