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/*
* Copyright (c) 1998, 2015, 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 javax.crypto.spec;
import java.security.MessageDigest;
import java.security.spec.KeySpec;
import java.util.Locale;
import javax.crypto.SecretKey;
/**
* This class specifies a secret key in a provider-independent fashion.
*
* <p>It can be used to construct a <code>SecretKey</code> from a byte array,
* without having to go through a (provider-based)
* <code>SecretKeyFactory</code>.
*
* <p>This class is only useful for raw secret keys that can be represented as
* a byte array and have no key parameters associated with them, e.g., DES or
* Triple DES keys.
*
* @author Jan Luehe
*
* @see javax.crypto.SecretKey
* @see javax.crypto.SecretKeyFactory
* @since 1.4
*/
public class SecretKeySpec implements KeySpec, SecretKey {
private static final long serialVersionUID = 6577238317307289933L;
/**
* The secret key.
*
* @serial
*/
private byte[] key;
/**
* The name of the algorithm associated with this key.
*
* @serial
*/
private String algorithm;
/**
* Constructs a secret key from the given byte array.
*
* <p>This constructor does not check if the given bytes indeed specify a
* secret key of the specified algorithm. For example, if the algorithm is
* DES, this constructor does not check if <code>key</code> is 8 bytes
* long, and also does not check for weak or semi-weak keys.
* In order for those checks to be performed, an algorithm-specific
* <i>key specification</i> class (in this case:
* {@link DESKeySpec DESKeySpec})
* should be used.
*
* @param key the key material of the secret key. The contents of
* the array are copied to protect against subsequent modification.
* @param algorithm the name of the secret-key algorithm to be associated
* with the given key material.
* See Appendix A in the <a href=
* "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA">
* Java Cryptography Architecture Reference Guide</a>
* for information about standard algorithm names.
* @exception IllegalArgumentException if <code>algorithm</code>
* is null or <code>key</code> is null or empty.
*/
public SecretKeySpec(byte[] key, String algorithm) {
if (key == null || algorithm == null) {
throw new IllegalArgumentException("Missing argument");
}
if (key.length == 0) {
throw new IllegalArgumentException("Empty key");
}
this.key = key.clone();
this.algorithm = algorithm;
}
/**
* Constructs a secret key from the given byte array, using the first
* <code>len</code> bytes of <code>key</code>, starting at
* <code>offset</code> inclusive.
*
* <p> The bytes that constitute the secret key are
* those between <code>key[offset]</code> and
* <code>key[offset+len-1]</code> inclusive.
*
* <p>This constructor does not check if the given bytes indeed specify a
* secret key of the specified algorithm. For example, if the algorithm is
* DES, this constructor does not check if <code>key</code> is 8 bytes
* long, and also does not check for weak or semi-weak keys.
* In order for those checks to be performed, an algorithm-specific key
* specification class (in this case:
* {@link DESKeySpec DESKeySpec})
* must be used.
*
* @param key the key material of the secret key. The first
* <code>len</code> bytes of the array beginning at
* <code>offset</code> inclusive are copied to protect
* against subsequent modification.
* @param offset the offset in <code>key</code> where the key material
* starts.
* @param len the length of the key material.
* @param algorithm the name of the secret-key algorithm to be associated
* with the given key material.
* See Appendix A in the <a href=
* "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA">
* Java Cryptography Architecture Reference Guide</a>
* for information about standard algorithm names.
* @exception IllegalArgumentException if <code>algorithm</code>
* is null or <code>key</code> is null, empty, or too short,
* i.e. {@code key.length-offset<len}.
* @exception ArrayIndexOutOfBoundsException is thrown if
* <code>offset</code> or <code>len</code> index bytes outside the
* <code>key</code>.
*/
public SecretKeySpec(byte[] key, int offset, int len, String algorithm) {
if (key == null || algorithm == null) {
throw new IllegalArgumentException("Missing argument");
}
if (key.length == 0) {
throw new IllegalArgumentException("Empty key");
}
if (key.length-offset < len) {
throw new IllegalArgumentException
("Invalid offset/length combination");
}
if (len < 0) {
throw new ArrayIndexOutOfBoundsException("len is negative");
}
this.key = new byte[len];
System.arraycopy(key, offset, this.key, 0, len);
this.algorithm = algorithm;
}
/**
* Returns the name of the algorithm associated with this secret key.
*
* @return the secret key algorithm.
*/
public String getAlgorithm() {
return this.algorithm;
}
/**
* Returns the name of the encoding format for this secret key.
*
* @return the string "RAW".
*/
public String getFormat() {
return "RAW";
}
/**
* Returns the key material of this secret key.
*
* @return the key material. Returns a new array
* each time this method is called.
*/
public byte[] getEncoded() {
return this.key.clone();
}
/**
* Calculates a hash code value for the object.
* Objects that are equal will also have the same hashcode.
*/
public int hashCode() {
int retval = 0;
for (int i = 1; i < this.key.length; i++) {
retval += this.key[i] * i;
}
if (this.algorithm.equalsIgnoreCase("TripleDES"))
return (retval ^= "desede".hashCode());
else
return (retval ^=
this.algorithm.toLowerCase(Locale.ENGLISH).hashCode());
}
/**
* Tests for equality between the specified object and this
* object. Two SecretKeySpec objects are considered equal if
* they are both SecretKey instances which have the
* same case-insensitive algorithm name and key encoding.
*
* @param obj the object to test for equality with this object.
*
* @return true if the objects are considered equal, false if
* <code>obj</code> is null or otherwise.
*/
public boolean equals(Object obj) {
if (this == obj)
return true;
if (!(obj instanceof SecretKey))
return false;
String thatAlg = ((SecretKey)obj).getAlgorithm();
if (!(thatAlg.equalsIgnoreCase(this.algorithm))) {
if ((!(thatAlg.equalsIgnoreCase("DESede"))
|| !(this.algorithm.equalsIgnoreCase("TripleDES")))
&& (!(thatAlg.equalsIgnoreCase("TripleDES"))
|| !(this.algorithm.equalsIgnoreCase("DESede"))))
return false;
}
byte[] thatKey = ((SecretKey)obj).getEncoded();
return MessageDigest.isEqual(this.key, thatKey);
}
}
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