240 lines
8.5 KiB
Java
240 lines
8.5 KiB
Java
/*
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* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package javax.crypto.spec;
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import java.security.spec.KeySpec;
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import java.util.Arrays;
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/**
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* A user-chosen password that can be used with password-based encryption
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* (<i>PBE</i>).
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*
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* <p>The password can be viewed as some kind of raw key material, from which
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* the encryption mechanism that uses it derives a cryptographic key.
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*
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* <p>Different PBE mechanisms may consume different bits of each password
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* character. For example, the PBE mechanism defined in
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* <a href="http://www.ietf.org/rfc/rfc2898.txt">
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* PKCS #5</a> looks at only the low order 8 bits of each character, whereas
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* PKCS #12 looks at all 16 bits of each character.
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*
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* <p>You convert the password characters to a PBE key by creating an
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* instance of the appropriate secret-key factory. For example, a secret-key
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* factory for PKCS #5 will construct a PBE key from only the low order 8 bits
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* of each password character, whereas a secret-key factory for PKCS #12 will
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* take all 16 bits of each character.
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*
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* <p>Also note that this class stores passwords as char arrays instead of
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* <code>String</code> objects (which would seem more logical), because the
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* String class is immutable and there is no way to overwrite its
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* internal value when the password stored in it is no longer needed. Hence,
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* this class requests the password as a char array, so it can be overwritten
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* when done.
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*
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* @author Jan Luehe
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* @author Valerie Peng
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*
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* @see javax.crypto.SecretKeyFactory
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* @see PBEParameterSpec
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* @since 1.4
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*/
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public class PBEKeySpec implements KeySpec {
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private char[] password;
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private byte[] salt = null;
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private int iterationCount = 0;
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private int keyLength = 0;
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/**
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* Constructor that takes a password. An empty char[] is used if
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* null is specified.
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*
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* <p> Note: <code>password</code> is cloned before it is stored in
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* the new <code>PBEKeySpec</code> object.
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*
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* @param password the password.
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*/
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public PBEKeySpec(char[] password) {
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if ((password == null) || (password.length == 0)) {
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this.password = new char[0];
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} else {
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this.password = password.clone();
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}
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}
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/**
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* Constructor that takes a password, salt, iteration count, and
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* to-be-derived key length for generating PBEKey of variable-key-size
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* PBE ciphers. An empty char[] is used if null is specified for
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* <code>password</code>.
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*
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* <p> Note: the <code>password</code> and <code>salt</code>
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* are cloned before they are stored in
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* the new <code>PBEKeySpec</code> object.
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*
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* @param password the password.
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* @param salt the salt.
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* @param iterationCount the iteration count.
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* @param keyLength the to-be-derived key length.
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* @exception NullPointerException if <code>salt</code> is null.
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* @exception IllegalArgumentException if <code>salt</code> is empty,
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* i.e. 0-length, <code>iterationCount</code> or
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* <code>keyLength</code> is not positive.
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*/
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public PBEKeySpec(char[] password, byte[] salt, int iterationCount,
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int keyLength) {
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if ((password == null) || (password.length == 0)) {
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this.password = new char[0];
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} else {
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this.password = password.clone();
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}
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if (salt == null) {
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throw new NullPointerException("the salt parameter " +
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"must be non-null");
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} else if (salt.length == 0) {
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throw new IllegalArgumentException("the salt parameter " +
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"must not be empty");
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} else {
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this.salt = salt.clone();
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}
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if (iterationCount<=0) {
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throw new IllegalArgumentException("invalid iterationCount value");
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}
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if (keyLength<=0) {
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throw new IllegalArgumentException("invalid keyLength value");
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}
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this.iterationCount = iterationCount;
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this.keyLength = keyLength;
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}
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/**
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* Constructor that takes a password, salt, iteration count for
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* generating PBEKey of fixed-key-size PBE ciphers. An empty
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* char[] is used if null is specified for <code>password</code>.
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*
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* <p> Note: the <code>password</code> and <code>salt</code>
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* are cloned before they are stored in the new
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* <code>PBEKeySpec</code> object.
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*
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* @param password the password.
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* @param salt the salt.
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* @param iterationCount the iteration count.
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* @exception NullPointerException if <code>salt</code> is null.
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* @exception IllegalArgumentException if <code>salt</code> is empty,
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* i.e. 0-length, or <code>iterationCount</code> is not positive.
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*/
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public PBEKeySpec(char[] password, byte[] salt, int iterationCount) {
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if ((password == null) || (password.length == 0)) {
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this.password = new char[0];
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} else {
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this.password = password.clone();
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}
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if (salt == null) {
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throw new NullPointerException("the salt parameter " +
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"must be non-null");
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} else if (salt.length == 0) {
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throw new IllegalArgumentException("the salt parameter " +
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"must not be empty");
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} else {
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this.salt = salt.clone();
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}
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if (iterationCount<=0) {
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throw new IllegalArgumentException("invalid iterationCount value");
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}
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this.iterationCount = iterationCount;
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}
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/**
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* Clears the internal copy of the password.
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*
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*/
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public final void clearPassword() {
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if (password != null) {
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Arrays.fill(password, ' ');
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password = null;
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}
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}
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/**
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* Returns a copy of the password.
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*
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* <p> Note: this method returns a copy of the password. It is
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* the caller's responsibility to zero out the password information after
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* it is no longer needed.
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*
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* @exception IllegalStateException if password has been cleared by
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* calling <code>clearPassword</code> method.
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* @return the password.
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*/
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public final char[] getPassword() {
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if (password == null) {
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throw new IllegalStateException("password has been cleared");
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}
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return password.clone();
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}
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/**
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* Returns a copy of the salt or null if not specified.
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*
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* <p> Note: this method should return a copy of the salt. It is
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* the caller's responsibility to zero out the salt information after
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* it is no longer needed.
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*
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* @return the salt.
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*/
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public final byte[] getSalt() {
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if (salt != null) {
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return salt.clone();
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} else {
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return null;
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}
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}
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/**
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* Returns the iteration count or 0 if not specified.
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*
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* @return the iteration count.
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*/
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public final int getIterationCount() {
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return iterationCount;
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}
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/**
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* Returns the to-be-derived key length or 0 if not specified.
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*
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* <p> Note: this is used to indicate the preference on key length
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* for variable-key-size ciphers. The actual key size depends on
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* each provider's implementation.
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*
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* @return the to-be-derived key length.
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*/
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public final int getKeyLength() {
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return keyLength;
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}
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}
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